Global Models of Refractive Error Service Delivery: a review of design, performance, and alignment with WHO SPECS 2030

Global Models of Refractive Error Service Delivery: a review of design, performance, and alignment with WHO SPECS 2030 | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Systematic Review Global Models of Refractive Error Service Delivery: a review of design, performance, and alignment with WHO SPECS 2030 Indra Prasad Sharma, Kovin Shunmugam Naidoo, Khathutshelo Percy Mashige, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8823477/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Despite substantial expansion of vision screening and refraction services, effective refractive error coverage (eREC) remains suboptimal, particularly in low- and middle-income countries. This persistent gap reflects systemic shortcomings beyond diagnosis, including weaknesses in spectacle dispensing, affordability, continuity of care, and outcome monitoring. Recent global policy shifts, including adoption of effective coverage indicators and the WHO SPECS 2030 framework, have reframed refractive error (RE) correction as a health-systems performance issue rather than a purely clinical intervention. However, robust comparative evidence identifying service delivery models that most effectively and sustainably improve eREC remains limited. Methods A narrative review was undertaken to examine global RE and optical service delivery models through a health-systems framework. Peer-reviewed literature and authoritative policy documents published between 2000 and March 2025 were systematically synthesised. Identified models were comparatively evaluated across the refractive care continuum using six performance dimensions: access, quality, affordability and equity, continuity of care, sustainability and system integration, and scalability. In addition, models were mapped against the WHO SPECS 2030 pillars, namely services, personnel, education, cost, and surveillance. Results Eight dominant eye-care service delivery models were identified: facility-based public sector services; private optical and social enterprise provision; school-based vision screening with spectacle provision; community outreach and mobile eye-camp services; tele-refraction and digitally enabled services; vision-centre- primary eye care models; public–private partnership (PPP) models; and social enterprise micro-entrepreneurship models. Models emphasizing rapid scale-up of screening and refraction achieved high population reach; however, they demonstrated suboptimal performance in continuity, affordability, surveillance, and sustainability of eREC. In contrast, vision-centre and PPP models showed consistently strong performance across all six evaluative dimensions, including scalability, and exhibited the closest alignment with the WHO SPECS 2030 framework. Across all models, systemic weaknesses namely fragile optical supply chains, limited pooled financing mechanisms, inadequate follow-up systems, and absence of routine outcome monitoring were identified as the key determinants of low effective coverage. Conclusion Achieving universal eREC constitutes primarily a health-systems challenge rather than a diagnostic limitation. The scale-up of refraction services in the absence of integrated dispensing pathways, sustainable financing mechanisms, routine surveillance, and continuity of care frameworks is unlikely to yield durable population-level impact. In contrast, vision-centre-based delivery models and PPP represent the most robust service architectures for delivering equitable, scalable, and sustainable eREC, in alignment with the WHO SPECS 2030 agenda. These models provide clear, actionable guidance for national eye-health policy formulation and programme implementation. refractive error service delivery models effective refractive error coverage WHO SPECS 2030 eye health systems narrative review Figures Figure 1 Figure 2 Introduction Effective refractive error coverage (eREC) has been established as a critical performance indicator for eye-health systems, as it reflects the entire continuum of refractive care, encompassing access to refraction services, provision of appropriate optical correction, and attainment of functional visual outcomes [ 1 , 2 ]. Unlike conventional coverage measures that primarily quantify service contact or delivery volumes, eREC integrates dimensions of quality and effectiveness, acknowledging that identification of refractive error (RE) alone is insufficient to ensure meaningful visual improvement [ 1 , 3 ]. Despite substantial global expansion in vision screening, refraction services, and spectacle distribution over the past decade, levels of eREC remain unacceptably low, particularly in low- and middle-income countries (LMICs) [ 4 , 5 ] Current estimates indicate that fewer than 50% of individuals requiring refractive correction achieve effective visual outcomes, underscoring persistent health-system shortcomings that extend beyond case detection and diagnosis [ 5 ]. These deficiencies predominantly arise at downstream stages of the refractive care continuum, including spectacle dispensing, affordability, optical quality, follow-up care, adherence to spectacle use, and systematic outcome monitoring [ 2 , 6 – 8 ]. Recent global policy developments have further heightened the significance of this challenge. The adoption of World Health Assembly Resolution WHA74.12 on Integrated People-Centred Eye Care (IPEC) reframed refractive services as an essential component of universal health coverage, rather than as stand-alone or campaign-based interventions [ 9 ]. The resolution endorsed a global target of a 40-percentage-point increase in eREC by 2030. In alignment with this mandate, the World Health Organization subsequently institutionalised eREC as a core global monitoring indicator, thereby shifting the evaluative focus from service delivery volumes to quality-adjusted outcomes that more accurately reflect functional vision and patient-centred benefit [ 10 ]. These policy milestones highlight the imperative for low- and middle-income countries (LMICs) to implement scalable, sustainable, and equity-oriented models of refractive care capable of supporting attainment of the 2030 eREC target. Progress towards this goal cannot be achieved through incremental service expansion alone; rather, it requires coordinated, system-level interventions to address persistent deficiencies in access, quality, and continuity of care, particularly within public health systems [ 11 ]. In this context, the WHO SPECS 2030 initiative advocates for harmonised engagement across public, private, and non-profit sectors to strengthen refractive-care service delivery through five interdependent pillars [ 12 ]. Collectively, these policy reforms emphasise the need for integrated strengthening of governance, financing mechanisms, workforce planning and deployment, service integration, optical supply chains, and health information systems to achieve high population-level eREC. Fragmented investments such as expanding screening in the absence of regulated dispensing, structured referral pathways, and adequate follow-up mechanisms; are unlikely to yield meaningful improvements in effective coverage. Conversely, sustained, coordinated investment in the eye care continuum, including comprehensive RE services, is associated with substantial health and demonstrable economic returns [ 13 ]. In practice, RE services are delivered through heterogeneous models, including facility-based public sector provision, private optical and social enterprise models, school-based vision screening programmes, outreach and mobile eye camps, tele-refraction platforms, vision centres integrated within primary health-care systems, public–private partnership (PPP) arrangements, and micro-entrepreneurial approaches [ 8 , 14 , 15 ]. Existing reviews have largely examined individual delivery platforms or clinical efficacy of interventions [ 16 ]. By contrast, there is a paucity of comparative evidence evaluating health-system performance across these models, particularly with respect to service integration, continuity of care, and alignment with the World Health Organization’s SPECS 2030 strategic pillars—Services, Personnel, Education, Cost, and Surveillance. Consequently, policy-makers lack robust, evidence-informed guidance on which refractive service delivery architectures are most effective in achieving sustained, population-level eREC. These limitations are particularly pronounced in small, publicly financed health systems such as that of Bhutan. In the absence of a clearly articulated national refractive service delivery framework, investments in screening, refraction, dispensing, and workforce development are likely to remain fragmented, inefficient, and suboptimal in terms of population-level impact. Against this backdrop, this review undertakes a critical analysis of prevailing global RE and optical service delivery models through a health-systems framework. The review comparatively assesses the refractive care continuum across six performance dimensions: access, quality, affordability and equity, continuity of care, sustainability and health-system integration, and scalability. In addition, it systematically assesses the extent to which these models align with the WHO SPECS 2030 strategic pillars; Services, Personnel, Education, Cost, and Surveillance. Through this analysis, the review seeks to identify service-delivery architectures capable of supporting sustained and equitable expanded refractive error care (eREC) and to generate evidence to inform national policy design and implementation in low- and middle-income country (LMIC) contexts. Methods Study design and rationale This study employed a narrative review design methodology to synthesise and critically appraise global models of RE and optical service delivery. A narrative approach was deemed appropriate given the complexity and multi-dimensional nature of service delivery frameworks, which encompass clinical care pathways, optical provision, governance arrangements, financing mechanisms, and health information systems. The evidence-base underpinning this review is heterogenous, comprising empirical research, programme and service evaluations, policy and systems analyses, and international normative guidance. Such methodological and contextual diversity precludes quantitative synthesis or meta-analysis but is well suited to a structured conceptual and comparative analysis. This approach enables the identification of patterns, gaps, and transferable principles across diverse health system contexts. A summary of the methodological approach is provided in Table S1 . Objectives The objectives of this review were threefold: (1) to identify and systematically categorise prevailing models of RE and optical service delivery; (2) to critically examine their structural design characteristics and performance across the continuum of refractive care; and (3) to assess their alignment with the WHO SPECS 2030 strategic pillars, with a view to informing evidence-based policy and health-system design, particularly within LMIC settings. Conceptual and analytical framework The review was underpinned by a health-systems analytical framework that integrated two complementary constructs. First, the model performance was assessed across six interrelated dimensions relevant to eREC: access, quality, affordability and equity, continuity of care, sustainability and system integration, and scalability. Second, the models were mapped against the WHO SPECS 2030 strategic pillars (services, personnel, education, cost, and surveillance) to assess the degree of health-system alignment across different service delivery models. Together, these frameworks guided evidence selection, data extraction, and comparative synthesis. Literature identification and sources A systematic and structured literature search was undertaken across PubMed/MEDLINE, Scopus, and Google Scholar, encompassing publications from January 2000 to March 2025. In addition to peer-reviewed sources, relevant grey literature was deliberately included to capture programme reports, global policy documents, and implementation guidance relevant to refractive service delivery and broader health-system reform. Search terms were developed through an iterative and systematic process and combined using Boolean operators. The search strategy incorporated key concepts including: refractive error , uncorrected refractive error , spectacle provision , optical services , eye care service delivery , primary eye care , vision centre , school vision screening , outreach eye camps , tele-refraction , effective refractive error coverage , health systems , public–private partnership , and universal health coverage . In addition, the reference lists of all included studies were manually screened to identify further relevant literature. Eligibility criteria Sources were eligible for inclusion if they met one or more of the following criteria; (1) described, analysed, or evaluated RE or optical service delivery models at local, national, or regional levels; (2) reported on service performance dimensions, including access, quality, affordability, equity, continuity of care, or service outcomes; (3) examined health system components relevant to refractive services, such as governance arrangements, financing mechanisms, workforce planning and deployment, supply chain management, or health information systems; and/or (4) provided policy, strategic, or implementation insights aligned with the WHO SPECS 2030 framework or the concept of effective coverage. Sources were excluded if they focused exclusively on clinical or surgical outcomes without consideration of service delivery or health system design, or if they lacked sufficient descriptive depth or analytical rigor to inform systems-level understanding. Identification and classification of service delivery models Through an iterative thematic synthesis, RE and optical service delivery approaches were categorised into eight dominant global service-delivery models. These models were delineated according to their primary platform of care, financing mechanisms, workforce composition, and level of integration within the broader health system: Facility-based public sector model Private optical and social enterprise model School-based vision screening and spectacle provision model Community outreach and mobile eye-camp model Tele-refraction and digital service model Vision-centre (primary eye care) model Public–private partnership (PPP) model Social enterprise micro-entrepreneur model These models were conceptualised as ideal types, acknowledging that many real-world programmes function as hybrid configuration or context-specific adaptations shaped by local health-system, socioeconomic, and regulatory conditions. Data extraction and synthesis For each model, data were narratively extracted on service design, target population, financing mechanisms, workforce composition and task-sharing arrangements, spectacle dispensing pathways, referral and follow-up mechanisms, and reported implementation challenges. Formal quality appraisal was not conducted, as this is not standard practice in narrative reviews; instead, sources were assessed for conceptual relevance, internal consistency across contexts, and significance for policy and system-level decision-making. Performance assessment Each service delivery model was subjected to a qualitative appraisal across six performance dimensions informed by the effective coverage literature. These included: Access, defined by population reach and service availability; Quality, assessed in terms of refractive accuracy, spectacle standards, and visual outcomes; Affordability and equity, reflecting financial protection and the inclusion of underserved populations; Continuity and follow-up, denoting linkage and coordination across the refractive care continuum; Sustainability and system integration, indicating alignment with national health systems and long-term operational viability; and Scalability, referring to the capacity of the model to expand and be replicated at scale without compromising quality or equity. Evidence was triangulated across multiple data sources to identify consistent performance patterns, thereby minimising reliance on single-study findings. Assessment of alignment with WHO SPECS 2030 Alignment with the WHO SPECS 2030 framework was assessed through a systematic mapping of each model’s structural components and operational characteristics against the five SPECS pillars. Particular attention was given to the degree to which the models facilitate integrated, people-centred care and support the sustainable provision of eREC, as opposed to episodic or fragmented service delivery. Contextual interpretation Findings were interpreted through a contextual analytic lens specific to LMIC and small, predominantly publicly financed health systems, with Bhutan used as an illustrative case. This approach enabled systematic examination of the interactions between geographic constraints, health-workforce capacity, financing mechanisms, and governance arrangements in shaping refractive service-delivery models. Emphasis was placed on assessing the contextual transferability of findings, rather than on direct generalisation across settings. Reporting transparency The review was conducted and reported using a transparent, systematic, and structured approach aligned with established best-practice standards for narrative reviews. Clearly defined objectives, explicit and reproducible literature identification strategies, coherent scientific rationale, and a balanced, critical interpretation of evidence were emphasised to enhance methodological rigour, transparency, overall credibility. Results Identification and classification of refractive error service delivery models The narrative synthesis identified eight dominant global RE and optical service delivery models, implemented either as stand-alone platforms or as hybrid configurations across diverse health-system contexts. As summarised in Table 1 , these models exhibit substantial heterogeneity in their primary platforms, financing mechanisms, workforce composition, and levels of integration within broader health-system structures. Table 1 Core characteristics of global refractive error service delivery models Model Primary platform Financing mechanism Workforce Level of system integration Facility-based public sector model Hospitals, government facilities Public budget Optometrists, ophthalmic technicians Moderate–high Private optical and social enterprise model Retail optical outlets/online Out-of-pocket / cross-subsidy Optometrists, opticians Low–moderate School-based vision screening and spectacle provision model Schools Public / donor-funded Teachers, visiting eye-care teams Low Community outreach and mobile eye-camp model Temporary community sites Donor / NGO-funded Ophthalmologists, optometrists, ophthalmic technicians Low Tele-refraction and digital service model Digital platforms Private / mixed Technicians with or without remote optometrists Low-moderate Vision-centre (primary eye care) model Community-based clinics Public / blended Vision technicians High Public–private partnership (PPP) model Mixed platforms Contracted public funding Mixed cadres High Social enterprise micro-entrepreneur model Door-to-door/community Sales-based Trained lay workers Low Substantial heterogeneity was observed in the design and implementation of the models across platforms, financing mechanisms, workforce configurations, and degrees of health-system integration. Facility-based public sector, vision-centre, and public–private partnership models demonstrated higher levels of system integration, whereas school-based, outreach, digital, and social enterprise models largely functioned as stand-alone or weakly integrated platforms. A comparative overview of the major RE models, including their strengths, limitations and scalability potential, is shown in Table 2 . Table 2 Comparative overview of prominent RE service delivery models So no Model Design / Approach Outcomes Strengths Limitations Scalability Examples of the models 1 Facility-Based Public Sector Model Refraction delivered through public hospitals, district hospitals, and PHCs by optometrists/technicians. Spectacles are often excluded or outsourced to private vendors. Public financing/subsidy. High diagnostic accuracy; strong referral integration; low consultation cost; low eREC when spectacles excluded. Strong clinical governance; high safety; integrated ocular disease management; pro-poor consultations. Fragmentation between refraction and dispensing; weak supply chains; long wait times; workforce shortages. High policy scalability, moderate operational scalability. Primary Eye Care Program, Bhutan [ 17 ] Sri Lanka National Eye Care Programme [ 18 ] Pakistan’s District Comprehensive Eye Care [ 19 ] The Giving Sight to KwaZulu-Natal [20} National Primary Eye Care Programme in Rwanda [ 21 , 22 ] 2 Private Optical & Social Enterprise Model Independent optometry clinics, retail optical chains, and social enterprises offering one-stop refraction + dispensing. OOP and cross-subsidy financing. High spectacle uptake among paying clients; continuity of care; limited rural and poor reach. Integrated clinical–dispensing pathway; rapid service; financial sustainability. Urban bias; exclusion of the poorest; weak regulation; risk of over-prescription. High commercial scalability, low equity scalability without subsidy. Lenskart (India) [ 23 ] Warby Parker (USA) [ 24 ] VisionSpring (Global) [ 25 ] 3 School-Based Vision Screening & Spectacle Provision Model Vision screening in schools by teachers or visiting teams; referral and free/subsidised spectacles. High detection of childhood myopia/hyperopia; improved school performance; variable spectacle compliance. Very high population reach; early detection; cost-effective. Weak referral and follow-up; excludes out-of-school children/adults. High scalability for children, dependent on financing and monitoring. Sri Lanka School Medical Inspection (SMI) [ 26 ] Sightsaver School Screening model in Pakistan [ 27 ] India NPCB School Eye Health Model [ 28 ] REACH model in India [ 29 , 30 ] Vietnam School Vision Programme [ 31 ] School-Based Delivery of Vision Care in Baltimore [ 32 ] 4 Community Outreach & Mobile Eye-Camp Model Periodic NGO-led mobile refraction teams in rural and underserved areas. Rapid backlog reduction; high rural uptake; weak continuity. Reaches last-mile populations; flexible deployment; rapid service expansion. Episodic care; weak HMIS integration; high logistics cost. Low long-term scalability unless converted to permanent services. Aravind Outreach Camps (India) [ 33 ] Flying Eye Hospital Model of Orbis International [ 34 ] Cure Blindness Project in South Asia and Africa [ 35 ] 5 Tele-Refraction & Digital Service Model Autorefractors + remote optometrist interpretation + digital prescribing. Improved access in remote areas; acceptable agreement for simple RE Addresses workforce shortages; reduces travel; digital records. Regulatory uncertainty; limited complex case handling; internet dependence. Moderate scalability, policy- and infrastructure-dependent. Peek Vision [ 36 ] Remote Autorefraction Pilots [ 37 ] EyeNetra Mobile Refraction [ 38 ] Digital optometrics [ 39 ] 6 Hybrid Public–Private Partnership (PPP) Model Public screening + refraction linked to regulated private or social-enterprise dispensing. Improved spectacle uptake; reduced OOP; higher eREC. Balances equity and sustainability; leverages private supply chains. Contract fragility; pricing regulation challenges; political dependence. High scalability with strong regulation. Vision for a Nation (Rwanda PPP) [ 40 ] Victorian Aboriginal Spectacle Subsidy Scheme (VASSS) [ 41 ] National Integrated People Centered Eye Care (IPEC) Plan in Sindh province, Pakistan [ 42 ] One Sight EssilorLuxottica Foundation in South East Asia and China [ 43 ] 7 Vision-Centre (Primary Eye Care) Model Permanent community eye centres serving 30,000–50,000 population; mid-level refractionists; hospital linkage. High rural access; improved follow-up; reduced tertiary load. Strong continuity; decentralised care; integrated referral, effective use of teleophthalmology Workforce retention; capital investment needs. Very high scalability when embedded in PHC. Vision Center Model in India [ 44 ] Aboriginal Eye and Vision care Program in NSW, Australia [ 45 ] 8 Social Enterprise plus Door-to-Door / Micro-Entrepreneur Model Community entrepreneurs screen and sell low-cost spectacles with referrals. Improved affordability; last-mile access; variable clinical accuracy. Ultra-low-cost; strong community trust; rapid rural scale-up. Limited clinical depth; weak regulation; inconsistent referrals. High scalability in remote contexts with supervision. Social Enterprise Model of Kenya [ 46 ] The Reading Glasses for Improved Livelihoods (RGIL) in Bangladesh and Uganda [ 47 ] Manhattan Vision Screening Model [ 48 ] Eye Mitra program in India [ 49 ] Performance of RE and optical service delivery models Performance varied substantially across RE service delivery models and across six interrelated dimensions central to eREC: access and population reach, quality of refraction and spectacle correction, affordability and equity, continuity of care and follow-up, sustainability and system integration, and scalability. Figure 1 summarises the comparative performance of eight service delivery models across these dimensions. Relative performance ratings (1 = low, 2 = moderate, 3 = high) were assigned to eight RE service delivery models across six dimensions relevant to eREC. These ratings were derived through qualitative synthesis of evidence across multiple sources and contexts and reflect comparative performance rather than pooled quantitative estimates. Access and population reach Outreach-oriented models demonstrated the greatest population coverage [ 8 ]. School-based vision screening with spectacle provision, as well as community outreach and mobile eye-camp models, consistently achieved high reach, particularly among children and populations in geographically remote settings. While these approaches were effective for large-scale detection of RE, they were predominantly episodic in nature and exhibited limited integration with routine, longitudinal care pathways [ 50 ]. Vision-centre-based primary eye care models and public–private partnership (PPP) arrangements demonstrated moderate yet sustained population access, attributable to clearly defined catchment areas and continuous service provision. In contrast, facility-based public sector models, while offering comprehensive service packages, exhibited restricted population reach in dispersed or hard-to-reach settings, largely due to geographic, infrastructural, and human-resource limitations [ 15 ]. Private optical and social enterprise models enabled rapid access, particularly in urban and peri-urban contexts; however, their socioeconomic and geographic selectivity constrained equitable, population-level coverage across many LMIC settings [ 51 ]. Quality of refraction and spectacle correction Quality of refraction and spectacle dispensing was superior in service delivery models characterised by standardised clinical protocols, adequately trained personnel, and well-defined referral pathways. Facility-based public sector services, vision-centre models, and PPP arrangements demonstrated more consistent adherence to accurate refraction, appropriate spectacle fitting, and effective clinical governance [ 52 ]. In contrast, the quality of school-based screening and community outreach models was variable. Identified limitations included inadequate dispensing oversight, inconsistent spectacle fitting, and suboptimal adherence, often compounded by low levels of parental awareness and eye-health literacy [ 53 ]. Evidence regarding the quality and long-term effectiveness of tele-refraction and other digital service delivery models remains limited, particularly in low- and middle-income country settings [ 54 ]. Across all models, detection or refraction in the absence of assured spectacle provision was consistently associated with poor functional visual outcomes, underscoring a persistent discontinuity within the refractive care continuum [ 50 ]. Affordability and equity Equity performance varied markedly across service delivery models. Facility-based public sector models, vision-centre models, and PPP arrangements demonstrated stronger financial protection where refraction and spectacles were subsidised or supported through pooled public financing mechanisms. These models were associated with greater inclusion of low-income and rural populations [ 55 , 56 ]. In addition, school-based vision screening and spectacle provision models improved equity among enrolled school-going children [ 53 , 57 ]. However, the model systematically excluded out-of-school children and adults, thereby limiting its contribution to population-level equity. In contrast, the private optical and social enterprise models, including micro-entrepreneurial approaches, relied largely on out-of-pocket payments, which exacerbated affordability constraints and resulted in inequitable service uptake in LMIC settings [ 58 ]. Continuity of care and follow-up Continuity of care beyond the initial refraction was consistently identified as a systemic weakness across most service delivery platforms. In particular, school-based screening and outreach models frequently lacked formalised referral pathways, mechanisms for spectacle repair or replacement, and structured follow-up to monitor adherence. These deficiencies contributed to significant patient attrition across successive stages of the refractive error continuum [ 57 , 59 ]. Private optical and social enterprise models demonstrated efficient refraction-to-dispensing workflows; however, they generally lacked structured mechanisms for systematic follow-up and outcome monitoring. In contrast, the vision-centre (primary eye care) and PPP models showed the highest levels of continuity of care, underpinned by defined catchment populations, formalised referral pathways, and integration with secondary-level services [ 60 , 61 ]. As summarised in Table 3 , performance varied across key stages of the refractive care continuum, with no single service delivery model consistently achieving high performance from case detection through effective visual outcomes. Table 3 Performance of global RE service delivery models across the refractive care continuum Service Delivery Model Detection / Screening Clinical Refraction Spectacle Dispensing Follow-up & Adherence Effective Visual Outcome (eREC) Facility-Based Public Sector High High Low Low Low Private Optical & Social Enterprise Moderate High High Moderate Moderate School-Based Screening Model High Low Low Very Low Very Low Community Outreach / Eye-Camp Model High Moderate Low Very Low Very Low Tele-Refraction & Digital Model Moderate Moderate Low–Moderate Very Low Very Low Hybrid PPP Model High High High Moderate Moderate–High Vision-Centre (Primary Eye Care) Model High High High High High Micro-Entrepreneur / Door-to-Door Model Moderate Low–Moderate Moderate Very Low Very Low Performance Coding : High=Consistently strong performance across multiple settings, Moderate= Context-dependent or mixed performance and Low / Very Low=Structural weakness or inconsistent performance Sustainability and system integration Sustainability was strongest among service models embedded within national health systems. Vision-centre models, facility-based public sector services, and PPP arrangements benefited from task-sharing, regulated optical supply chains, and recurrent financing mechanisms, thereby supporting long-term service delivery [ 15 ]. However, the sustainability of fully publicly funded RE services remains challenging in LMICs [ 17 , 21 ]. In contrast, outreach-based and tele-refraction models demonstrated limited sustainability, largely due to reliance on external funding, infrastructure constraints, and regulatory uncertainty. Social-enterprise micro-entrepreneurial models showed variable sustainability and were weakly integrated into formal health systems [ 62 ]. Scalability Scalability differed substantially across service delivery models. It was strongly influenced by workforce composition, financing mechanisms, and degree of system integration [ 63 ]. Vision-centre and PPP models demonstrated the highest scalability, attributable to their reliance on mid-level health personnel, standardised service packages, and effective integration with primary health care platforms and referral pathways [ 44 ]. Facility-based public sector models exhibited constrained scalability in resource-limited settings, primarily due to their dependence on specialised human resources and fixed infrastructure. School-based and outreach models achieved rapid scale-up for vision screening; however, they lacked scalable systems for spectacle dispensing, continuity of care, and systemic outcome monitoring. Evidence supporting the scalable implementation of tele-refraction models remains limited, emergent, and highly context-specific [ 64 ]. Alignment of RE service delivery models with WHO SPECS 2030 Mapping RE service delivery models against the WHO SPECS 2030 strategic pillars (services, personnel, education, cost, and surveillance) demonstrated marked heterogeneity in structural alignment and levels of health system readiness (Fig. 2 , Table 4 ). Services Vision-centre-based primary eye care models and public–private partnership (PPP) approaches demonstrated the strongest alignment with the “Services” pillar, as they consistently provided routine access to refraction, integrated spectacle dispensing, clearly defined referral pathways, and continuity of care [ 44 , 65 ]. In contrast, school-based screening and community outreach models were primarily episodic in nature, with limited capacity for follow-up or integration into ongoing care pathways [ 53 ]. Facility-based public sector models offered comprehensive clinical services; however, their population-level reach was comparatively constrained in geographically dispersed settings [ 66 ]. Personnel Alignment with the “Personnel” pillar was strongest in service delivery models that incorporated task-sharing and mid-level eye-care cadres, particularly vision-centre and PPP models [ 67 ]. In contrast, facility-based public sector models relied mainly on higher-level personnel, which limited scalability. Private optical and social enterprise models showed heterogeneous workforce distribution and inconsistent quality-assurance mechanisms, particularly within LMIC settings [ 68 ]. Education Few service delivery models systematically addressed the “Education” pillar. School-based screening models aligned most directly this dimension through the incorporation of health education activities; however, their reach was largely confined to children enrolled in formal schooling [ 53 ]. Moreover, even in contexts where population reach was inadequate, existing health education interventions demonstrated limited effectiveness [ 50 ]. Vision-centre and PPP models incorporated elements of provider training; however, these approaches generally lacked formalised and systematic community education strategies [ 69 ]. The tele-refraction and digital service delivery model showed emerging potential to support provider training and clinical decision-making, but robust evidence of effectiveness and scalability remain limited [ 54 ]. Cost Alignment with the “Cost” pillar exhibited substantial heterogeneity across service delivery models. Publicly financed approaches, including facility-based public sector services, vision-centre models, and PPP models, demonstrated stronger alignment through the use of subsidised or pooled financing mechanisms for refraction and spectacle provision [ 70 ]. By contrast, private optical, social enterprise, and micro-entrepreneurial models were predominantly dependent on out-of-pocket payments, thereby limiting affordability and equitable utilisation, including high-income settings such as Singapore [ 71 ]. School-based programmes were effective in reducing direct costs for children; however, they did not adequately address long-term refractive care or the needs of the adult population [ 72 ]. Surveillance Alignment with the Surveillance pillar was generally weak across most service delivery models, as emphasised in the World Report on Vision [ 10 ]. Routine monitoring of refractive outcomes, spectacle use, and eREC was largely absent, particularly within school-based, outreach, and private optical care models [ 1 ]. Vision-centre and PPP models demonstrated relatively stronger surveillance capacity, attributable to partial integration with health information systems; however, systematic and comprehensive monitoring of eREC remained limited even within these models [ 73 ]. Table 4 Alignment of global RE service delivery models with the five strategic pillars of WHO SPECS 2030 WHO SPECS 2030 Strategic Pillar Strategic Objective Best-Aligned Models Moderately Aligned Models Poorly Aligned Models Key System Gaps Identified Services Improve access to refractive services across the life course Vision-centre (primary eye-care) model; Hybrid PPP model; Facility-based public sector model Private optical and social enterprise model; Tele-refraction and digital service model Community outreach and mobile eye-camp model; School-based vision screening and spectacle provision model; Social enterprise micro-entrepreneur (door-to-door) model Fragmented care pathways; weak continuity beyond screening; exclusion of spectacle dispensing from public services Personnel Build capacity of personnel to provide refractive services Vision-centre (primary eye-care) model; Facility-based public sector model; Hybrid PPP model Tele-refraction and digital service model Community outreach and mobile eye-camp model; Social enterprise micro-entrepreneur (door-to-door) model Maldistribution of optometrists; limited career progression for mid-level refractionists; rural retention challenges Education Improve population education, awareness, and adherence School-based vision screening and spectacle provision model; Vision-centre (primary eye-care) model Community outreach and mobile eye-camp model; Social enterprise micro-entrepreneur (door-to-door) model Facility-based public sector model; Private optical and social enterprise model Limited adult awareness programmes; weak counselling on spectacle use; minimal behaviour-change interventions Cost Reduce the cost of refractive services and out-of-pocket expenditure Hybrid PPP model; Facility-based public sector model; Vision-centre (primary eye-care) model School-based vision screening and spectacle provision model; Social enterprise micro-entrepreneur (door-to-door) model Private optical and social enterprise model; Community outreach and mobile eye-camp model Spectacles excluded from benefit packages; price variability; weak regulation of optical markets Surveillance Strengthen surveillance, HMIS integration, and research Facility-based public sector model; Vision-centre (primary eye-care) model; Hybrid PPP model Tele-refraction and digital service model Community outreach and mobile eye-camp model; School-based vision screening and spectacle provision model; Social enterprise micro-entrepreneur (door-to-door) model Poor routine outcome monitoring; limited eREC reporting; weak integration with national HMIS Implications for eREC Across service delivery models, high levels of screening or refraction coverage did not consistently correspond to high effective refractive error coverage (eREC), demonstrating that service availability alone is insufficient to achieve effective coverage. The greatest attrition was observed at the stages of spectacle dispensing, affordability, treatment adherence and outcome monitoring, particularly in models lacking regulated optical care pathways and structured follow-up systems. In contrast, the evidence consistently indicated that integrated service delivery models, characterised by the anchoring of refraction within primary health care, regulated spectacle supply chains, pooled or pre-paid financing mechanisms, and routine outcome monitoring, were most effective in sustaining improvements in population-level eREC. Such models minimise discontinuities along the refractive care continuum and more effectively translate service coverage into durable visual outcomes and equity gains. Discussion This review demonstrates that achieving high effective refractive error coverage (eREC) is fundamentally a health-systems challenge rather than a purely diagnostic or technological one. Across service models, expansion of screening and refraction activities alone did not consistently translate into improved functional visual outcomes. Instead, recurrent discontinuities were observed at downstream stages of care, particularly in spectacle dispensing, affordability, and outcome monitoring. Collectively, these findings underscore that effective coverage is contingent on integrated, end-to-end care pathways rather than isolated expansion of individual service components [ 1 , 10 , 74 ]. A key finding was that service delivery models prioritising rapid scale-up of case detection often demonstrated weaker performance in sustainability, equity, and long-term visual outcomes. School-based screening and outreach programmes achieved high population coverage, particularly among children and rural populations [ 57 ]. However, deficiencies in referral pathways, variability in spectacle dispensing quality, and inadequate follow-up substantially constrained their contribution to sustained effective refractive error coverage (eREC). This observation is consistent with prior evidence indicating that case detection in the absence of integrated spectacle provision and structured post-screening care is associated with high attrition and low spectacle uptake [ 50 ]. In contrast, vision-centre (primary eye care) models and hybrid public–private partnership (PPP) models demonstrated consistently superior performance across the full refractive care continuum [ 8 , 60 ]. Their relative effectiveness is attributable to four key structural attributes: clearly defined catchment populations, decentralised and community-based service delivery, regulated and quality-assured spectacle supply chains, and formal integration with referral pathways and health information platforms [ 15 , 44 , 75 ]. These features facilitate continuity across the refractive error continuum from case detection and refraction to spectacle dispensing and follow-up which is critical for achieving and sustaining optimal visual outcomes. In recognition of this, many organisations that initially depended on community outreach and mobile eye-camp approaches are increasingly transitioning towards vision-centre–based primary eye care and hybrid public–private partnership (PPP) models to strengthen continuity of care, system sustainability, and long-term visual outcomes. A central determinant of quality in high-performing service delivery models is the strategic integration of optometrists as clinical and quality anchors within refractive care systems [ 76 ]. Models that embedded optometrists within integrated service platforms, particularly vision centres and PPP arrangements, demonstrated greater consistency in clinical standards, improved spectacle quality, and more favourable patient outcomes [ 77 ]. The findings align with an emerging global consensus that mid-level eye-care cadres and task-sharing are essential for achieving scalable refractive care delivery, particularly in low-resource settings [ 51 , 78 , 79 ]. Service models that rely on specialist optometrists or hospital-based infrastructure demonstrate limited geographic coverage and slower rates of scale-up. In contrast, platforms that deploy trained vision technicians within primary-care settings exhibit greater scalability, improved cost-efficiency, and stronger service retention at the community level [ 76 ]. These patterns indicate the need for an evolution of optometry towards a hybrid professional role that combines specialist clinical leadership with the training and supervision of mid-level providers, alongside broader public-health and health-systems strengthening functions [ 80 ]. Consistent with this perspective, earlier literature has long highlighted the potential of optometry to serve as a key public-health advocate for eye care [ 81 – 83 ]. Affordability is a major determinant of equity and effective service coverage [ 84 ]. Service delivery m​odels reliant on out-of-pocket payments, including private optical and micro-entrepreneurial approaches, demonstrated consistently poorer performance among low-income and rural populations. Even where low-cost spectacles were available, price variability and weak regulatory oversight limited equitable uptake. In contrast, pooled public financing and regulated public–private partnership pricing mechanisms were associated with improved access to spectacles and reduced risk of catastrophic health expenditure, underscoring the importance of integrating refractive services within broader universal health coverage frameworks. A persistent limitation observed in nearly all service delivery models was the absence of robust surveillance systems and routine monitoring of refractive outcomes. Few platforms systematically tracked spectacle utilisation, functional visual outcomes, or eREC at scale. This deficiency undermines accountability and limits the capacity of health systems to evaluate performance and implement data-driven improvements. These findings are consistent with concerns articulated in the World Report on Vision regarding inadequate outcome monitoring within eye-health programmes [ 10 ]. Strengthening integration with health information systems and institutionalising routine eREC reporting should therefore be regarded as a core system requirement rather than an optional adjunct [ 2 ]. Alignment with the WHO SPECS 2030 framework varied considerably across service delivery models. Vision-centre and PPP models demonstrated the strongest across multiple pillars, particularly Services, Personnel, and Cost. Nevertheless, even these relatively high-performing models exhibited systemic underinvestment in Education and Surveillance, representing missed opportunities to strengthen treatment adherence, enhance community awareness, and improve long-term visual outcomes [ 6 ]. The integration of structured education components across all delivery models is therefore critical, as inadequate advocacy and persistent misconceptions regarding spectacle use are well-documented contributors to poor compliance with spectacle wear [ 85 – 86 ]. The findings that expansion of technical service capacity alone is insufficient unless accompanied by complementary behavioural, educational, and data-driven interventions—domains in which optometry-led public health initiatives can play a substantive role [ 87 ]. These insights have particular relevance for low- and middle-income countries (LMICs), where fragmented investments in screening programmes, short-term outreach activities, or stand-alone technology-driven solutions may generate high service throughput but limited population-level impact. The evidence therefore supports prioritisation of integrated national service architectures over isolated vertical programmes. Specifically, the integration of refractive services within primary health care systems, the strengthening of regulated optical supply chains, and the strategic contracting of private providers through performance-based public–private partnerships emerge as the most feasible approaches for achieving scalable, equitable, and sustainable effective refractive error coverage (eREC) [ 11 ]. The applicability of these findings to small, publicly financed health systems such as Bhutan is especially salient. The parallel existence of facility-based public services, outreach programmes, and nascent private optical markets reflects the fragmented service delivery landscape identified in this review. In the absence of an integrated national delivery framework, investments in workforce development, screening coverage, and spectacle provision are likely to remain poorly coordinated, with suboptimal efficiency and impact. A vision-centre–anchored service delivery model, supported by regulated public–private partnership dispensing mechanisms and integrated surveillance systems, represents a potentially pragmatic and scalable approach to strengthening national effective refractive error coverage (eREC) [ 60 ]. Strengths and limitations This review synthesised evidence across diverse service delivery models, policy environments, and implementation contexts, offering a systems-oriented comparative perspective that is seldom addressed in existing literature. Key strengths include the application of a systems-based analytical framework, explicit alignment with WHO SPECS 2030 framework, and an emphasis on effective coverage rather than service volume. However, the narrative review design precludes the generation of pooled quantitative estimates, and the conclusions are derived from qualitative synthesis of heterogeneous sources. Future directions and research priorities Future research should prioritize comparative implementation studies that extend beyond service coverage to include measures of effective refractive services (eREC), spectacle adherence, cost-effectiveness, and long-term visual function outcomes. There is a clear need for standardised outcome indicators, integrated surveillance systems, and longitudinal designs capable of assessing sustainability beyond pilot or demonstration phases. In addition, rigorous evaluation of hybrid digital–primary care delivery models, regulated low-cost spectacle supply chains, and behaviourally informed interventions to improve spectacle adherence is warranted, as these approaches may generate actionable evidence to support attainment of the SPECS 2030 targets. Conclusion and policy relevance This review demonstrates that eREC is fundamentally a health-systems performance challenge rather than a diagnostic limitation. Expansion of refraction services in isolation is insufficient to achieve meaningful improvements in visual outcomes. Instead, sustained gains in eREC require system-wide integration across service delivery platforms, financing mechanisms, workforce capacity, optical supply chains, continuity of care, and routine monitoring and surveillance. Across the models, vision-centre primary eye-care systems and hybrid PPP approaches consistently show the greatest alignment with WHO SPECS 2030 priorities, with superior capacity to convert service availability into equitable, scalable, and durable population-level visual benefit. By contrast, outreach, school-based, and micro-entrepreneurial models—although effective for case detection and short-term access—are constrained by limited follow-up, fragmented delivery pathways, and weak integration within broader health systems, thereby restricting their impact on sustained effective coverage. To achieve effective refractive error services (eREC) targets, policy efforts should shift beyond short-term service expansion toward the development of coherent, system-level national refractive service delivery models. Strategic priorities include the establishment of integrated and sustainable financing mechanisms, optimisation of the eye-care workforce through appropriate task-sharing, regulation of optical markets, strengthening of health information systems, and institutionalisation of routine eREC monitoring and evaluation. Critically, aligning refractive services with the principles of Integrated People-Centred Eye Care (IPEC) within the framework of universal health coverage is essential to ensure that increased service availability translates into effective, equitable, and improved visual outcomes at population level. Declarations Clinical trial number Not applicable. Ethics approval and consent to participate Ethical approval for the overarching study was obtained from the Research Ethics Board of Health (REBH), Ministry of Health, Bhutan (Ref: REBH/Approval/2023/003), and the Biomedical Research Ethics Committee (BREC) of the University of KwaZulu-Natal, South Africa (Approval No: BREC/00004482/2022). The approvals covered the development of an evidence-based model to address uncorrected refractive error in Bhutan. The present work constitutes a component of the broader model-development study; therefore, separate ethical approval was not required. As this study was conducted as a narrative review, it did not involve human participants. Consent for publication Not applicable. Competing interests All authors declare no competing interests. Funding No funding was received for this work. Author Contribution IPS served as the study’s principal investigator. IPS, KSN and KPM jointly conceptualized the study protocol and design. 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Sharma","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6UlEQVRIiWNgGAWjYBACNgYGAxCdAOZ9AImwk6KFcQZIhJmwRQgtzDxgkoB6PunmbR9+7qjL4599OvGzza9t8nzMDIwfPubgcZjMseKZvWcOF0ucy90sndt327CNmYFZcuY2PFokcowZeNsOJDac4d0gndtzmxGohY2Zl4AWxr9tdYnzz/Bu/m3Zc9ueKC3MvG3MiRvO8G6TZvhxO5EILWnFzLJnDiduBGqx7G24ndzGzNiM1y/yM5I3M77dUZc4D+iwGz/+3Lad39588MNHPFrAgLEBxmhD4RKjheEPYcWjYBSMglEw8gAA0dBPqfiTjAsAAAAASUVORK5CYII=","orcid":"","institution":"Jigme Dorji Wangchuck National Referral Hospital","correspondingAuthor":true,"prefix":"","firstName":"Indra","middleName":"Prasad","lastName":"Sharma","suffix":""},{"id":588003095,"identity":"5a60078b-e6e4-4265-819e-993fd7aa753f","order_by":1,"name":"Kovin Shunmugam Naidoo","email":"","orcid":"","institution":"University of KwaZulu-Natal","correspondingAuthor":false,"prefix":"","firstName":"Kovin","middleName":"Shunmugam","lastName":"Naidoo","suffix":""},{"id":588003097,"identity":"98e5f752-0762-4f99-8867-47d32dbda85d","order_by":2,"name":"Khathutshelo Percy Mashige","email":"","orcid":"","institution":"University of KwaZulu-Natal","correspondingAuthor":false,"prefix":"","firstName":"Khathutshelo","middleName":"Percy","lastName":"Mashige","suffix":""},{"id":588003099,"identity":"80cfe6c0-89bb-4a15-affe-6370da7c97ed","order_by":3,"name":"Nor Tshering Lepcha","email":"","orcid":"","institution":"Jigme Dorji Wangchuck National Referral Hospital","correspondingAuthor":false,"prefix":"","firstName":"Nor","middleName":"Tshering","lastName":"Lepcha","suffix":""}],"badges":[],"createdAt":"2026-02-08 17:54:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8823477/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8823477/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":102306283,"identity":"9fe5fe91-c2f8-41b9-b0a6-7c0d4a926b8a","added_by":"auto","created_at":"2026-02-10 11:41:02","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":166658,"visible":true,"origin":"","legend":"\u003cp\u003eHeatmap of performance across refractive error service delivery models.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8823477/v1/9337ebc5fd6a8ac73933c5bb.png"},{"id":102306538,"identity":"3840671e-bfc8-4b2b-a43d-ef063e918071","added_by":"auto","created_at":"2026-02-10 11:41:36","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":174719,"visible":true,"origin":"","legend":"\u003cp\u003eConceptual mapping of the alignment of integrated refractive error service delivery models with the WHO SPECS 2030 strategic pillars\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8823477/v1/fe3f4a41e4a3c2b2bbc094e9.jpeg"},{"id":103865410,"identity":"3d750e3e-cb6f-4a00-9185-aa70d7a7f9f0","added_by":"auto","created_at":"2026-03-03 21:54:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1765121,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8823477/v1/30477254-2778-495d-a05f-f21352d7c0f8.pdf"},{"id":102306407,"identity":"4321d395-fd07-41c9-9248-9adad8f19d3a","added_by":"auto","created_at":"2026-02-10 11:41:24","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":565852,"visible":true,"origin":"","legend":"","description":"","filename":"S1TableMethodologicalcomponent.docx","url":"https://assets-eu.researchsquare.com/files/rs-8823477/v1/defcf9da524c6b3571b84c2a.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Global Models of Refractive Error Service Delivery: a review of design, performance, and alignment with WHO SPECS 2030","fulltext":[{"header":"Introduction","content":"\u003cp\u003eEffective refractive error coverage (eREC) has been established as a critical performance indicator for eye-health systems, as it reflects the entire continuum of refractive care, encompassing access to refraction services, provision of appropriate optical correction, and attainment of functional visual outcomes [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Unlike conventional coverage measures that primarily quantify service contact or delivery volumes, eREC integrates dimensions of quality and effectiveness, acknowledging that identification of refractive error (RE) alone is insufficient to ensure meaningful visual improvement [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDespite substantial global expansion in vision screening, refraction services, and spectacle distribution over the past decade, levels of eREC remain unacceptably low, particularly in low- and middle-income countries (LMICs) [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] Current estimates indicate that fewer than 50% of individuals requiring refractive correction achieve effective visual outcomes, underscoring persistent health-system shortcomings that extend beyond case detection and diagnosis [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. These deficiencies predominantly arise at downstream stages of the refractive care continuum, including spectacle dispensing, affordability, optical quality, follow-up care, adherence to spectacle use, and systematic outcome monitoring [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eRecent global policy developments have further heightened the significance of this challenge. The adoption of World Health Assembly Resolution WHA74.12 on Integrated People-Centred Eye Care (IPEC) reframed refractive services as an essential component of universal health coverage, rather than as stand-alone or campaign-based interventions [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The resolution endorsed a global target of a 40-percentage-point increase in eREC by 2030. In alignment with this mandate, the World Health Organization subsequently institutionalised eREC as a core global monitoring indicator, thereby shifting the evaluative focus from service delivery volumes to quality-adjusted outcomes that more accurately reflect functional vision and patient-centred benefit [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThese policy milestones highlight the imperative for low- and middle-income countries (LMICs) to implement scalable, sustainable, and equity-oriented models of refractive care capable of supporting attainment of the 2030 eREC target. Progress towards this goal cannot be achieved through incremental service expansion alone; rather, it requires coordinated, system-level interventions to address persistent deficiencies in access, quality, and continuity of care, particularly within public health systems [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In this context, the WHO SPECS 2030 initiative advocates for harmonised engagement across public, private, and non-profit sectors to strengthen refractive-care service delivery through five interdependent pillars [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Collectively, these policy reforms emphasise the need for integrated strengthening of governance, financing mechanisms, workforce planning and deployment, service integration, optical supply chains, and health information systems to achieve high population-level eREC.\u003c/p\u003e \u003cp\u003eFragmented investments such as expanding screening in the absence of regulated dispensing, structured referral pathways, and adequate follow-up mechanisms; are unlikely to yield meaningful improvements in effective coverage. Conversely, sustained, coordinated investment in the eye care continuum, including comprehensive RE services, is associated with substantial health and demonstrable economic returns [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn practice, RE services are delivered through heterogeneous models, including facility-based public sector provision, private optical and social enterprise models, school-based vision screening programmes, outreach and mobile eye camps, tele-refraction platforms, vision centres integrated within primary health-care systems, public\u0026ndash;private partnership (PPP) arrangements, and micro-entrepreneurial approaches [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Existing reviews have largely examined individual delivery platforms or clinical efficacy of interventions [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. By contrast, there is a paucity of comparative evidence evaluating health-system performance across these models, particularly with respect to service integration, continuity of care, and alignment with the World Health Organization\u0026rsquo;s SPECS 2030 strategic pillars\u0026mdash;Services, Personnel, Education, Cost, and Surveillance.\u003c/p\u003e \u003cp\u003eConsequently, policy-makers lack robust, evidence-informed guidance on which refractive service delivery architectures are most effective in achieving sustained, population-level eREC. These limitations are particularly pronounced in small, publicly financed health systems such as that of Bhutan. In the absence of a clearly articulated national refractive service delivery framework, investments in screening, refraction, dispensing, and workforce development are likely to remain fragmented, inefficient, and suboptimal in terms of population-level impact.\u003c/p\u003e \u003cp\u003eAgainst this backdrop, this review undertakes a critical analysis of prevailing global RE and optical service delivery models through a health-systems framework. The review comparatively assesses the refractive care continuum across six performance dimensions: access, quality, affordability and equity, continuity of care, sustainability and health-system integration, and scalability. In addition, it systematically assesses the extent to which these models align with the WHO SPECS 2030 strategic pillars; Services, Personnel, Education, Cost, and Surveillance. Through this analysis, the review seeks to identify service-delivery architectures capable of supporting sustained and equitable expanded refractive error care (eREC) and to generate evidence to inform national policy design and implementation in low- and middle-income country (LMIC) contexts.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and rationale\u003c/h2\u003e \u003cp\u003eThis study employed a narrative review design methodology to synthesise and critically appraise global models of RE and optical service delivery. A narrative approach was deemed appropriate given the complexity and multi-dimensional nature of service delivery frameworks, which encompass clinical care pathways, optical provision, governance arrangements, financing mechanisms, and health information systems. The evidence-base underpinning this review is heterogenous, comprising empirical research, programme and service evaluations, policy and systems analyses, and international normative guidance. Such methodological and contextual diversity precludes quantitative synthesis or meta-analysis but is well suited to a structured conceptual and comparative analysis. This approach enables the identification of patterns, gaps, and transferable principles across diverse health system contexts. A summary of the methodological approach is provided in \u003cb\u003eTable \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e\u003c/b\u003e.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eObjectives\u003c/h3\u003e\n\u003cp\u003eThe objectives of this review were threefold: (1) to identify and systematically categorise prevailing models of RE and optical service delivery; (2) to critically examine their structural design characteristics and performance across the continuum of refractive care; and (3) to assess their alignment with the WHO SPECS 2030 strategic pillars, with a view to informing evidence-based policy and health-system design, particularly within LMIC settings.\u003c/p\u003e\n\u003ch3\u003eConceptual and analytical framework\u003c/h3\u003e\n\u003cp\u003eThe review was underpinned by a health-systems analytical framework that integrated two complementary constructs. First, the model performance was assessed across six interrelated dimensions relevant to eREC: access, quality, affordability and equity, continuity of care, sustainability and system integration, and scalability. Second, the models were mapped against the WHO SPECS 2030 strategic pillars (services, personnel, education, cost, and surveillance) to assess the degree of health-system alignment across different service delivery models. Together, these frameworks guided evidence selection, data extraction, and comparative synthesis.\u003c/p\u003e\n\u003ch3\u003eLiterature identification and sources\u003c/h3\u003e\n\u003cp\u003eA systematic and structured literature search was undertaken across PubMed/MEDLINE, Scopus, and Google Scholar, encompassing publications from January 2000 to March 2025. In addition to peer-reviewed sources, relevant grey literature was deliberately included to capture programme reports, global policy documents, and implementation guidance relevant to refractive service delivery and broader health-system reform.\u003c/p\u003e \u003cp\u003eSearch terms were developed through an iterative and systematic process and combined using Boolean operators. The search strategy incorporated key concepts including: \u003cem\u003erefractive error\u003c/em\u003e, \u003cem\u003euncorrected refractive error\u003c/em\u003e, \u003cem\u003espectacle provision\u003c/em\u003e, \u003cem\u003eoptical services\u003c/em\u003e, \u003cem\u003eeye care service delivery\u003c/em\u003e, \u003cem\u003eprimary eye care\u003c/em\u003e, \u003cem\u003evision centre\u003c/em\u003e, \u003cem\u003eschool vision screening\u003c/em\u003e, \u003cem\u003eoutreach eye camps\u003c/em\u003e, \u003cem\u003etele-refraction\u003c/em\u003e, \u003cem\u003eeffective refractive error coverage\u003c/em\u003e, \u003cem\u003ehealth systems\u003c/em\u003e, \u003cem\u003epublic\u0026ndash;private partnership\u003c/em\u003e, and \u003cem\u003euniversal health coverage\u003c/em\u003e. In addition, the reference lists of all included studies were manually screened to identify further relevant literature.\u003c/p\u003e\n\u003ch3\u003eEligibility criteria\u003c/h3\u003e\n\u003cp\u003eSources were eligible for inclusion if they met one or more of the following criteria; (1) described, analysed, or evaluated RE or optical service delivery models at local, national, or regional levels; (2) reported on service performance dimensions, including access, quality, affordability, equity, continuity of care, or service outcomes; (3) examined health system components relevant to refractive services, such as governance arrangements, financing mechanisms, workforce planning and deployment, supply chain management, or health information systems; and/or (4) provided policy, strategic, or implementation insights aligned with the WHO SPECS 2030 framework or the concept of effective coverage. Sources were excluded if they focused exclusively on clinical or surgical outcomes without consideration of service delivery or health system design, or if they lacked sufficient descriptive depth or analytical rigor to inform systems-level understanding.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eIdentification and classification of service delivery models\u003c/h2\u003e \u003cp\u003eThrough an iterative thematic synthesis, RE and optical service delivery approaches were categorised into eight dominant global service-delivery models. These models were delineated according to their primary platform of care, financing mechanisms, workforce composition, and level of integration within the broader health system:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eFacility-based public sector model\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003ePrivate optical and social enterprise model\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eSchool-based vision screening and spectacle provision model\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eCommunity outreach and mobile eye-camp model\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eTele-refraction and digital service model\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eVision-centre (primary eye care) model\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003ePublic\u0026ndash;private partnership (PPP) model\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eSocial enterprise micro-entrepreneur model\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eThese models were conceptualised as ideal types, acknowledging that many real-world programmes function as hybrid configuration or context-specific adaptations shaped by local health-system, socioeconomic, and regulatory conditions.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eData extraction and synthesis\u003c/h3\u003e\n\u003cp\u003eFor each model, data were narratively extracted on service design, target population, financing mechanisms, workforce composition and task-sharing arrangements, spectacle dispensing pathways, referral and follow-up mechanisms, and reported implementation challenges. Formal quality appraisal was not conducted, as this is not standard practice in narrative reviews; instead, sources were assessed for conceptual relevance, internal consistency across contexts, and significance for policy and system-level decision-making.\u003c/p\u003e\n\u003ch3\u003ePerformance assessment\u003c/h3\u003e\n\u003cp\u003eEach service delivery model was subjected to a qualitative appraisal across six performance dimensions informed by the effective coverage literature. These included:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eAccess, defined by population reach and service availability;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eQuality, assessed in terms of refractive accuracy, spectacle standards, and visual outcomes;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eAffordability and equity, reflecting financial protection and the inclusion of underserved populations;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eContinuity and follow-up, denoting linkage and coordination across the refractive care continuum;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eSustainability and system integration, indicating alignment with national health systems and long-term operational viability; and\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eScalability, referring to the capacity of the model to expand and be replicated at scale without compromising quality or equity.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eEvidence was triangulated across multiple data sources to identify consistent performance patterns, thereby minimising reliance on single-study findings.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eAssessment of alignment with WHO SPECS 2030\u003c/h2\u003e \u003cp\u003eAlignment with the WHO SPECS 2030 framework was assessed through a systematic mapping of each model\u0026rsquo;s structural components and operational characteristics against the five SPECS pillars. Particular attention was given to the degree to which the models facilitate integrated, people-centred care and support the sustainable provision of eREC, as opposed to episodic or fragmented service delivery.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eContextual interpretation\u003c/h2\u003e \u003cp\u003eFindings were interpreted through a contextual analytic lens specific to LMIC and small, predominantly publicly financed health systems, with Bhutan used as an illustrative case. This approach enabled systematic examination of the interactions between geographic constraints, health-workforce capacity, financing mechanisms, and governance arrangements in shaping refractive service-delivery models. Emphasis was placed on assessing the contextual transferability of findings, rather than on direct generalisation across settings.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eReporting transparency\u003c/h2\u003e \u003cp\u003eThe review was conducted and reported using a transparent, systematic, and structured approach aligned with established best-practice standards for narrative reviews. Clearly defined objectives, explicit and reproducible literature identification strategies, coherent scientific rationale, and a balanced, critical interpretation of evidence were emphasised to enhance methodological rigour, transparency, overall credibility.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eIdentification and classification of refractive error service delivery models\u003c/h2\u003e \u003cp\u003eThe narrative synthesis identified eight dominant global RE and optical service delivery models, implemented either as stand-alone platforms or as hybrid configurations across diverse health-system contexts. As summarised in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, these models exhibit substantial heterogeneity in their primary platforms, financing mechanisms, workforce composition, and levels of integration within broader health-system structures.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCore characteristics of global refractive error service delivery models\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eModel\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePrimary platform\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFinancing mechanism\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eWorkforce\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLevel of system integration\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFacility-based public sector model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHospitals, government facilities\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePublic budget\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOptometrists, ophthalmic technicians\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eModerate\u0026ndash;high\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrivate optical and social enterprise model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRetail optical outlets/online\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOut-of-pocket / cross-subsidy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOptometrists, opticians\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLow\u0026ndash;moderate\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSchool-based vision screening and spectacle provision model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSchools\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePublic / donor-funded\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTeachers, visiting eye-care teams\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCommunity outreach and mobile eye-camp model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTemporary community sites\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDonor / NGO-funded\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOphthalmologists, optometrists, ophthalmic technicians\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTele-refraction and digital service model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDigital platforms\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePrivate / mixed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTechnicians with or without remote optometrists\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLow-moderate\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVision-centre (primary eye care) model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCommunity-based clinics\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePublic / blended\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVision technicians\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePublic\u0026ndash;private partnership (PPP) model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMixed platforms\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eContracted public funding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMixed cadres\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSocial enterprise micro-entrepreneur model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDoor-to-door/community\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSales-based\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTrained lay workers\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eSubstantial heterogeneity was observed in the design and implementation of the models across platforms, financing mechanisms, workforce configurations, and degrees of health-system integration. Facility-based public sector, vision-centre, and public\u0026ndash;private partnership models demonstrated higher levels of system integration, whereas school-based, outreach, digital, and social enterprise models largely functioned as stand-alone or weakly integrated platforms. A comparative overview of the major RE models, including their strengths, limitations and scalability potential, is shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparative overview of prominent RE service delivery models\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSo no\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eModel\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDesign / Approach\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOutcomes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eStrengths\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eLimitations\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eScalability\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eExamples of the models\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFacility-Based Public Sector Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRefraction delivered through public hospitals, district hospitals, and PHCs by optometrists/technicians. Spectacles are often excluded or outsourced to private vendors. Public financing/subsidy.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHigh diagnostic accuracy; strong referral integration; low consultation cost; low eREC when spectacles excluded.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eStrong clinical governance; high safety; integrated ocular disease management; pro-poor consultations.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eFragmentation between refraction and dispensing; weak supply chains; long wait times; workforce shortages.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eHigh policy scalability, moderate operational scalability.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003ePrimary Eye Care Program, Bhutan [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eSri Lanka National Eye Care Programme [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/p\u003e \u003cp\u003ePakistan\u0026rsquo;s District Comprehensive Eye Care [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe Giving Sight to KwaZulu-Natal [20}\u003c/p\u003e \u003cp\u003eNational Primary Eye Care Programme in Rwanda [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePrivate Optical \u0026amp; Social Enterprise Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eIndependent optometry clinics, retail optical chains, and social enterprises offering one-stop refraction\u0026thinsp;+\u0026thinsp;dispensing. OOP and cross-subsidy financing.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHigh spectacle uptake among paying clients; continuity of care; limited rural and poor reach.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eIntegrated clinical\u0026ndash;dispensing pathway; rapid service; financial sustainability.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eUrban bias; exclusion of the poorest; weak regulation; risk of over-prescription.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eHigh commercial scalability, low equity scalability without subsidy.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eLenskart (India) [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eWarby Parker (USA) [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eVisionSpring (Global) [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSchool-Based Vision Screening \u0026amp; Spectacle Provision Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eVision screening in schools by teachers or visiting teams; referral and free/subsidised spectacles.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHigh detection of childhood myopia/hyperopia; improved school performance; variable spectacle compliance.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eVery high population reach; early detection; cost-effective.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eWeak referral and follow-up; excludes out-of-school children/adults.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eHigh scalability for children, dependent on financing and monitoring.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eSri Lanka School Medical Inspection (SMI) [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eSightsaver School Screening model in Pakistan [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eIndia NPCB School Eye Health Model [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eREACH model in India [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eVietnam School Vision Programme [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eSchool-Based Delivery of Vision Care in Baltimore [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCommunity Outreach \u0026amp; Mobile Eye-Camp Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePeriodic NGO-led mobile refraction teams in rural and underserved areas.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRapid backlog reduction; high rural uptake; weak continuity.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eReaches last-mile populations; flexible deployment; rapid service expansion.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eEpisodic care; weak HMIS integration; high logistics cost.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eLow long-term scalability unless converted to permanent services.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eAravind Outreach Camps (India) [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eFlying Eye Hospital Model of Orbis International [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eCure Blindness Project in South Asia and Africa [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTele-Refraction \u0026amp; Digital Service Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAutorefractors\u0026thinsp;+\u0026thinsp;remote optometrist interpretation\u0026thinsp;+\u0026thinsp;digital prescribing.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eImproved access in remote areas; acceptable agreement for simple RE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAddresses workforce shortages; reduces travel; digital records.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eRegulatory uncertainty; limited complex case handling; internet dependence.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eModerate scalability, policy- and infrastructure-dependent.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003ePeek Vision [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eRemote Autorefraction Pilots [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eEyeNetra Mobile Refraction [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eDigital optometrics [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHybrid Public\u0026ndash;Private Partnership (PPP) Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePublic screening\u0026thinsp;+\u0026thinsp;refraction linked to regulated private or social-enterprise dispensing.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eImproved spectacle uptake; reduced OOP; higher eREC.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eBalances equity and sustainability; leverages private supply chains.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eContract fragility; pricing regulation challenges; political dependence.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eHigh scalability with strong regulation.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eVision for a Nation (Rwanda PPP) [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eVictorian Aboriginal Spectacle Subsidy Scheme (VASSS) [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eNational Integrated People Centered Eye Care (IPEC) Plan in Sindh province, Pakistan [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eOne Sight EssilorLuxottica Foundation in South East Asia and China [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVision-Centre (Primary Eye Care) Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePermanent community eye centres serving 30,000\u0026ndash;50,000 population; mid-level refractionists; hospital linkage.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHigh rural access; improved follow-up; reduced tertiary load.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eStrong continuity; decentralised care; integrated referral, effective use of teleophthalmology\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eWorkforce retention; capital investment needs.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eVery high scalability when embedded in PHC.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eVision Center Model in India [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eAboriginal Eye and Vision care Program in NSW, Australia [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSocial Enterprise plus Door-to-Door / Micro-Entrepreneur Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCommunity entrepreneurs screen and sell low-cost spectacles with referrals.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eImproved affordability; last-mile access; variable clinical accuracy.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eUltra-low-cost; strong community trust; rapid rural scale-up.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eLimited clinical depth; weak regulation; inconsistent referrals.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eHigh scalability in remote contexts with supervision.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eSocial Enterprise Model of Kenya [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe Reading Glasses for Improved Livelihoods (RGIL) in Bangladesh and Uganda [\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eManhattan Vision Screening Model\u003c/p\u003e \u003cp\u003e[\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eEye Mitra program in India [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003ePerformance of RE and optical service delivery models\u003c/h2\u003e \u003cp\u003ePerformance varied substantially across RE service delivery models and across six interrelated dimensions central to eREC: access and population reach, quality of refraction and spectacle correction, affordability and equity, continuity of care and follow-up, sustainability and system integration, and scalability. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarises the comparative performance of eight service delivery models across these dimensions.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eRelative performance ratings (1\u0026thinsp;=\u0026thinsp;low, 2\u0026thinsp;=\u0026thinsp;moderate, 3\u0026thinsp;=\u0026thinsp;high) were assigned to eight RE service delivery models across six dimensions relevant to eREC. These ratings were derived through qualitative synthesis of evidence across multiple sources and contexts and reflect comparative performance rather than pooled quantitative estimates.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eAccess and population reach\u003c/h2\u003e \u003cp\u003eOutreach-oriented models demonstrated the greatest population coverage [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. School-based vision screening with spectacle provision, as well as community outreach and mobile eye-camp models, consistently achieved high reach, particularly among children and populations in geographically remote settings. While these approaches were effective for large-scale detection of RE, they were predominantly episodic in nature and exhibited limited integration with routine, longitudinal care pathways [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eVision-centre-based primary eye care models and public\u0026ndash;private partnership (PPP) arrangements demonstrated moderate yet sustained population access, attributable to clearly defined catchment areas and continuous service provision. In contrast, facility-based public sector models, while offering comprehensive service packages, exhibited restricted population reach in dispersed or hard-to-reach settings, largely due to geographic, infrastructural, and human-resource limitations [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Private optical and social enterprise models enabled rapid access, particularly in urban and peri-urban contexts; however, their socioeconomic and geographic selectivity constrained equitable, population-level coverage across many LMIC settings [\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eQuality of refraction and spectacle correction\u003c/h2\u003e \u003cp\u003eQuality of refraction and spectacle dispensing was superior in service delivery models characterised by standardised clinical protocols, adequately trained personnel, and well-defined referral pathways. Facility-based public sector services, vision-centre models, and PPP arrangements demonstrated more consistent adherence to accurate refraction, appropriate spectacle fitting, and effective clinical governance [\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn contrast, the quality of school-based screening and community outreach models was variable. Identified limitations included inadequate dispensing oversight, inconsistent spectacle fitting, and suboptimal adherence, often compounded by low levels of parental awareness and eye-health literacy [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. Evidence regarding the quality and long-term effectiveness of tele-refraction and other digital service delivery models remains limited, particularly in low- and middle-income country settings [\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e]. Across all models, detection or refraction in the absence of assured spectacle provision was consistently associated with poor functional visual outcomes, underscoring a persistent discontinuity within the refractive care continuum [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003eAffordability and equity\u003c/h2\u003e \u003cp\u003eEquity performance varied markedly across service delivery models. Facility-based public sector models, vision-centre models, and PPP arrangements demonstrated stronger financial protection where refraction and spectacles were subsidised or supported through pooled public financing mechanisms. These models were associated with greater inclusion of low-income and rural populations [\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]. In addition, school-based vision screening and spectacle provision models improved equity among enrolled school-going children [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e, \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHowever, the model systematically excluded out-of-school children and adults, thereby limiting its contribution to population-level equity. In contrast, the private optical and social enterprise models, including micro-entrepreneurial approaches, relied largely on out-of-pocket payments, which exacerbated affordability constraints and resulted in inequitable service uptake in LMIC settings [\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003eContinuity of care and follow-up\u003c/h2\u003e \u003cp\u003eContinuity of care beyond the initial refraction was consistently identified as a systemic weakness across most service delivery platforms. In particular, school-based screening and outreach models frequently lacked formalised referral pathways, mechanisms for spectacle repair or replacement, and structured follow-up to monitor adherence. These deficiencies contributed to significant patient attrition across successive stages of the refractive error continuum [\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePrivate optical and social enterprise models demonstrated efficient refraction-to-dispensing workflows; however, they generally lacked structured mechanisms for systematic follow-up and outcome monitoring. In contrast, the vision-centre (primary eye care) and PPP models showed the highest levels of continuity of care, underpinned by defined catchment populations, formalised referral pathways, and integration with secondary-level services [\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e]. As summarised in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, performance varied across key stages of the refractive care continuum, with no single service delivery model consistently achieving high performance from case detection through effective visual outcomes.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePerformance of global RE service delivery models across the refractive care continuum\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eService Delivery Model\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDetection / Screening\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eClinical Refraction\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSpectacle Dispensing\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFollow-up \u0026amp; Adherence\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eEffective Visual Outcome (eREC)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFacility-Based Public Sector\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrivate Optical \u0026amp; Social Enterprise\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSchool-Based Screening Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eVery Low\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eVery Low\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCommunity Outreach / Eye-Camp Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eVery Low\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eVery Low\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTele-Refraction \u0026amp; Digital Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLow\u0026ndash;Moderate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eVery Low\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eVery Low\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHybrid PPP Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eModerate\u0026ndash;High\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVision-Centre (Primary Eye Care) Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMicro-Entrepreneur / Door-to-Door Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLow\u0026ndash;Moderate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eVery Low\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eVery Low\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e\u003cb\u003ePerformance Coding\u003c/b\u003e: \u003cem\u003eHigh=Consistently strong performance across multiple settings, Moderate= Context-dependent or mixed performance and Low / Very Low=Structural weakness or inconsistent performance\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003eSustainability and system integration\u003c/h2\u003e \u003cp\u003eSustainability was strongest among service models embedded within national health systems. Vision-centre models, facility-based public sector services, and PPP arrangements benefited from task-sharing, regulated optical supply chains, and recurrent financing mechanisms, thereby supporting long-term service delivery [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. However, the sustainability of fully publicly funded RE services remains challenging in LMICs [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. In contrast, outreach-based and tele-refraction models demonstrated limited sustainability, largely due to reliance on external funding, infrastructure constraints, and regulatory uncertainty. Social-enterprise micro-entrepreneurial models showed variable sustainability and were weakly integrated into formal health systems [\u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e62\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003eScalability\u003c/h2\u003e \u003cp\u003eScalability differed substantially across service delivery models. It was strongly influenced by workforce composition, financing mechanisms, and degree of system integration [\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e]. Vision-centre and PPP models demonstrated the highest scalability, attributable to their reliance on mid-level health personnel, standardised service packages, and effective integration with primary health care platforms and referral pathways [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFacility-based public sector models exhibited constrained scalability in resource-limited settings, primarily due to their dependence on specialised human resources and fixed infrastructure. School-based and outreach models achieved rapid scale-up for vision screening; however, they lacked scalable systems for spectacle dispensing, continuity of care, and systemic outcome monitoring. Evidence supporting the scalable implementation of tele-refraction models remains limited, emergent, and highly context-specific [\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec23\" class=\"Section3\"\u003e \u003ch2\u003eAlignment of RE service delivery models with WHO SPECS 2030\u003c/h2\u003e \u003cp\u003eMapping RE service delivery models against the WHO SPECS 2030 strategic pillars (services, personnel, education, cost, and surveillance) demonstrated marked heterogeneity in structural alignment and levels of health system readiness (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eServices\u003c/strong\u003e \u003cp\u003eVision-centre-based primary eye care models and public\u0026ndash;private partnership (PPP) approaches demonstrated the strongest alignment with the \u0026ldquo;Services\u0026rdquo; pillar, as they consistently provided routine access to refraction, integrated spectacle dispensing, clearly defined referral pathways, and continuity of care [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e, \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e]. In contrast, school-based screening and community outreach models were primarily episodic in nature, with limited capacity for follow-up or integration into ongoing care pathways [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. Facility-based public sector models offered comprehensive clinical services; however, their population-level reach was comparatively constrained in geographically dispersed settings [\u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e66\u003c/span\u003e].\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003ePersonnel\u003c/strong\u003e \u003cp\u003eAlignment with the \u0026ldquo;Personnel\u0026rdquo; pillar was strongest in service delivery models that incorporated task-sharing and mid-level eye-care cadres, particularly vision-centre and PPP models [\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e]. In contrast, facility-based public sector models relied mainly on higher-level personnel, which limited scalability. Private optical and social enterprise models showed heterogeneous workforce distribution and inconsistent quality-assurance mechanisms, particularly within LMIC settings [\u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e68\u003c/span\u003e].\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEducation\u003c/strong\u003e \u003cp\u003eFew service delivery models systematically addressed the \u0026ldquo;Education\u0026rdquo; pillar. School-based screening models aligned most directly this dimension through the incorporation of health education activities; however, their reach was largely confined to children enrolled in formal schooling [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. Moreover, even in contexts where population reach was inadequate, existing health education interventions demonstrated limited effectiveness [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e].\u003c/p\u003e \u003c/p\u003e \u003cp\u003eVision-centre and PPP models incorporated elements of provider training; however, these approaches generally lacked formalised and systematic community education strategies [\u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e69\u003c/span\u003e]. The tele-refraction and digital service delivery model showed emerging potential to support provider training and clinical decision-making, but robust evidence of effectiveness and scalability remain limited [\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eCost\u003c/strong\u003e \u003cp\u003eAlignment with the \u0026ldquo;Cost\u0026rdquo; pillar exhibited substantial heterogeneity across service delivery models. Publicly financed approaches, including facility-based public sector services, vision-centre models, and PPP models, demonstrated stronger alignment through the use of subsidised or pooled financing mechanisms for refraction and spectacle provision [\u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e70\u003c/span\u003e]. By contrast, private optical, social enterprise, and micro-entrepreneurial models were predominantly dependent on out-of-pocket payments, thereby limiting affordability and equitable utilisation, including high-income settings such as Singapore [\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e71\u003c/span\u003e]. School-based programmes were effective in reducing direct costs for children; however, they did not adequately address long-term refractive care or the needs of the adult population [\u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e72\u003c/span\u003e].\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eSurveillance\u003c/strong\u003e \u003cp\u003eAlignment with the Surveillance pillar was generally weak across most service delivery models, as emphasised in the World Report on Vision [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Routine monitoring of refractive outcomes, spectacle use, and eREC was largely absent, particularly within school-based, outreach, and private optical care models [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Vision-centre and PPP models demonstrated relatively stronger surveillance capacity, attributable to partial integration with health information systems; however, systematic and comprehensive monitoring of eREC remained limited even within these models [\u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e73\u003c/span\u003e].\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAlignment of global RE service delivery models with the five strategic pillars of WHO SPECS 2030\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWHO SPECS 2030 Strategic Pillar\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStrategic Objective\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBest-Aligned Models\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eModerately Aligned Models\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePoorly Aligned Models\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eKey System Gaps Identified\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eServices\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eImprove access to refractive services across the life course\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eVision-centre (primary eye-care) model; Hybrid PPP model; Facility-based public sector model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePrivate optical and social enterprise model; Tele-refraction and digital service model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCommunity outreach and mobile eye-camp model; School-based vision screening and spectacle provision model; Social enterprise micro-entrepreneur (door-to-door) model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eFragmented care pathways; weak continuity beyond screening; exclusion of spectacle dispensing from public services\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePersonnel\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBuild capacity of personnel to provide refractive services\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eVision-centre (primary eye-care) model; Facility-based public sector model; Hybrid PPP model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTele-refraction and digital service model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCommunity outreach and mobile eye-camp model; Social enterprise micro-entrepreneur (door-to-door) model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eMaldistribution of optometrists; limited career progression for mid-level refractionists; rural retention challenges\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEducation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eImprove population education, awareness, and adherence\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSchool-based vision screening and spectacle provision model; Vision-centre (primary eye-care) model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCommunity outreach and mobile eye-camp model; Social enterprise micro-entrepreneur (door-to-door) model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFacility-based public sector model; Private optical and social enterprise model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eLimited adult awareness programmes; weak counselling on spectacle use; minimal behaviour-change interventions\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCost\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eReduce the cost of refractive services and out-of-pocket expenditure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHybrid PPP model; Facility-based public sector model; Vision-centre (primary eye-care) model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSchool-based vision screening and spectacle provision model; Social enterprise micro-entrepreneur (door-to-door) model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePrivate optical and social enterprise model; Community outreach and mobile eye-camp model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSpectacles excluded from benefit packages; price variability; weak regulation of optical markets\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSurveillance\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStrengthen surveillance, HMIS integration, and research\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFacility-based public sector model; Vision-centre (primary eye-care) model; Hybrid PPP model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTele-refraction\u003c/p\u003e \u003cp\u003eand digital service model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCommunity outreach and mobile eye-camp model; School-based vision screening and spectacle provision model; Social enterprise micro-entrepreneur (door-to-door) model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePoor routine outcome monitoring; limited eREC reporting; weak integration with national HMIS\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section2\"\u003e \u003ch2\u003eImplications for eREC\u003c/h2\u003e \u003cp\u003eAcross service delivery models, high levels of screening or refraction coverage did not consistently correspond to high effective refractive error coverage (eREC), demonstrating that service availability alone is insufficient to achieve effective coverage. The greatest attrition was observed at the stages of spectacle dispensing, affordability, treatment adherence and outcome monitoring, particularly in models lacking regulated optical care pathways and structured follow-up systems. In contrast, the evidence consistently indicated that integrated service delivery models, characterised by the anchoring of refraction within primary health care, regulated spectacle supply chains, pooled or pre-paid financing mechanisms, and routine outcome monitoring, were most effective in sustaining improvements in population-level eREC. Such models minimise discontinuities along the refractive care continuum and more effectively translate service coverage into durable visual outcomes and equity gains.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis review demonstrates that achieving high effective refractive error coverage (eREC) is fundamentally a health-systems challenge rather than a purely diagnostic or technological one. Across service models, expansion of screening and refraction activities alone did not consistently translate into improved functional visual outcomes. Instead, recurrent discontinuities were observed at downstream stages of care, particularly in spectacle dispensing, affordability, and outcome monitoring. Collectively, these findings underscore that effective coverage is contingent on integrated, end-to-end care pathways rather than isolated expansion of individual service components [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e74\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eA key finding was that service delivery models prioritising rapid scale-up of case detection often demonstrated weaker performance in sustainability, equity, and long-term visual outcomes. School-based screening and outreach programmes achieved high population coverage, particularly among children and rural populations [\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e]. However, deficiencies in referral pathways, variability in spectacle dispensing quality, and inadequate follow-up substantially constrained their contribution to sustained effective refractive error coverage (eREC). This observation is consistent with prior evidence indicating that case detection in the absence of integrated spectacle provision and structured post-screening care is associated with high attrition and low spectacle uptake [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn contrast, vision-centre (primary eye care) models and hybrid public\u0026ndash;private partnership (PPP) models demonstrated consistently superior performance across the full refractive care continuum [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e]. Their relative effectiveness is attributable to four key structural attributes: clearly defined catchment populations, decentralised and community-based service delivery, regulated and quality-assured spectacle supply chains, and formal integration with referral pathways and health information platforms [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e, \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e75\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThese features facilitate continuity across the refractive error continuum from case detection and refraction to spectacle dispensing and follow-up which is critical for achieving and sustaining optimal visual outcomes. In recognition of this, many organisations that initially depended on community outreach and mobile eye-camp approaches are increasingly transitioning towards vision-centre\u0026ndash;based primary eye care and hybrid public\u0026ndash;private partnership (PPP) models to strengthen continuity of care, system sustainability, and long-term visual outcomes. A central determinant of quality in high-performing service delivery models is the strategic integration of optometrists as clinical and quality anchors within refractive care systems [\u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e76\u003c/span\u003e]. Models that embedded optometrists within integrated service platforms, particularly vision centres and PPP arrangements, demonstrated greater consistency in clinical standards, improved spectacle quality, and more favourable patient outcomes [\u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e77\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe findings align with an emerging global consensus that mid-level eye-care cadres and task-sharing are essential for achieving scalable refractive care delivery, particularly in low-resource settings [\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e, \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e78\u003c/span\u003e, \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e79\u003c/span\u003e]. Service models that rely on specialist optometrists or hospital-based infrastructure demonstrate limited geographic coverage and slower rates of scale-up. In contrast, platforms that deploy trained vision technicians within primary-care settings exhibit greater scalability, improved cost-efficiency, and stronger service retention at the community level [\u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e76\u003c/span\u003e]. These patterns indicate the need for an evolution of optometry towards a hybrid professional role that combines specialist clinical leadership with the training and supervision of mid-level providers, alongside broader public-health and health-systems strengthening functions [\u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e80\u003c/span\u003e]. Consistent with this perspective, earlier literature has long highlighted the potential of optometry to serve as a key public-health advocate for eye care [\u003cspan additionalcitationids=\"CR82\" citationid=\"CR81\" class=\"CitationRef\"\u003e81\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR83\" class=\"CitationRef\"\u003e83\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAffordability is a major determinant of equity and effective service coverage [\u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e84\u003c/span\u003e]. Service delivery m​odels reliant on out-of-pocket payments, including private optical and micro-entrepreneurial approaches, demonstrated consistently poorer performance among low-income and rural populations. Even where low-cost spectacles were available, price variability and weak regulatory oversight limited equitable uptake. In contrast, pooled public financing and regulated public\u0026ndash;private partnership pricing mechanisms were associated with improved access to spectacles and reduced risk of catastrophic health expenditure, underscoring the importance of integrating refractive services within broader universal health coverage frameworks.\u003c/p\u003e \u003cp\u003eA persistent limitation observed in nearly all service delivery models was the absence of robust surveillance systems and routine monitoring of refractive outcomes. Few platforms systematically tracked spectacle utilisation, functional visual outcomes, or eREC at scale. This deficiency undermines accountability and limits the capacity of health systems to evaluate performance and implement data-driven improvements. These findings are consistent with concerns articulated in the World Report on Vision regarding inadequate outcome monitoring within eye-health programmes [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Strengthening integration with health information systems and institutionalising routine eREC reporting should therefore be regarded as a core system requirement rather than an optional adjunct [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAlignment with the WHO SPECS 2030 framework varied considerably across service delivery models. Vision-centre and PPP models demonstrated the strongest across multiple pillars, particularly Services, Personnel, and Cost. Nevertheless, even these relatively high-performing models exhibited systemic underinvestment in Education and Surveillance, representing missed opportunities to strengthen treatment adherence, enhance community awareness, and improve long-term visual outcomes [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. The integration of structured education components across all delivery models is therefore critical, as inadequate advocacy and persistent misconceptions regarding spectacle use are well-documented contributors to poor compliance with spectacle wear [\u003cspan citationid=\"CR85\" class=\"CitationRef\"\u003e85\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR86\" class=\"CitationRef\"\u003e86\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe findings that expansion of technical service capacity alone is insufficient unless accompanied by complementary behavioural, educational, and data-driven interventions\u0026mdash;domains in which optometry-led public health initiatives can play a substantive role [\u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e87\u003c/span\u003e]. These insights have particular relevance for low- and middle-income countries (LMICs), where fragmented investments in screening programmes, short-term outreach activities, or stand-alone technology-driven solutions may generate high service throughput but limited population-level impact. The evidence therefore supports prioritisation of integrated national service architectures over isolated vertical programmes. Specifically, the integration of refractive services within primary health care systems, the strengthening of regulated optical supply chains, and the strategic contracting of private providers through performance-based public\u0026ndash;private partnerships emerge as the most feasible approaches for achieving scalable, equitable, and sustainable effective refractive error coverage (eREC) [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe applicability of these findings to small, publicly financed health systems such as Bhutan is especially salient. The parallel existence of facility-based public services, outreach programmes, and nascent private optical markets reflects the fragmented service delivery landscape identified in this review. In the absence of an integrated national delivery framework, investments in workforce development, screening coverage, and spectacle provision are likely to remain poorly coordinated, with suboptimal efficiency and impact. A vision-centre\u0026ndash;anchored service delivery model, supported by regulated public\u0026ndash;private partnership dispensing mechanisms and integrated surveillance systems, represents a potentially pragmatic and scalable approach to strengthening national effective refractive error coverage (eREC) [\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec26\" class=\"Section2\"\u003e \u003ch2\u003eStrengths and limitations\u003c/h2\u003e \u003cp\u003eThis review synthesised evidence across diverse service delivery models, policy environments, and implementation contexts, offering a systems-oriented comparative perspective that is seldom addressed in existing literature. Key strengths include the application of a systems-based analytical framework, explicit alignment with WHO SPECS 2030 framework, and an emphasis on effective coverage rather than service volume. However, the narrative review design precludes the generation of pooled quantitative estimates, and the conclusions are derived from qualitative synthesis of heterogeneous sources.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec27\" class=\"Section2\"\u003e \u003ch2\u003eFuture directions and research priorities\u003c/h2\u003e \u003cp\u003eFuture research should prioritize comparative implementation studies that extend beyond service coverage to include measures of effective refractive services (eREC), spectacle adherence, cost-effectiveness, and long-term visual function outcomes. There is a clear need for standardised outcome indicators, integrated surveillance systems, and longitudinal designs capable of assessing sustainability beyond pilot or demonstration phases. In addition, rigorous evaluation of hybrid digital\u0026ndash;primary care delivery models, regulated low-cost spectacle supply chains, and behaviourally informed interventions to improve spectacle adherence is warranted, as these approaches may generate actionable evidence to support attainment of the SPECS 2030 targets.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec28\" class=\"Section2\"\u003e \u003ch2\u003eConclusion and policy relevance\u003c/h2\u003e \u003cp\u003eThis review demonstrates that eREC is fundamentally a health-systems performance challenge rather than a diagnostic limitation. Expansion of refraction services in isolation is insufficient to achieve meaningful improvements in visual outcomes. Instead, sustained gains in eREC require system-wide integration across service delivery platforms, financing mechanisms, workforce capacity, optical supply chains, continuity of care, and routine monitoring and surveillance. Across the models, vision-centre primary eye-care systems and hybrid PPP approaches consistently show the greatest alignment with WHO SPECS 2030 priorities, with superior capacity to convert service availability into equitable, scalable, and durable population-level visual benefit. By contrast, outreach, school-based, and micro-entrepreneurial models\u0026mdash;although effective for case detection and short-term access\u0026mdash;are constrained by limited follow-up, fragmented delivery pathways, and weak integration within broader health systems, thereby restricting their impact on sustained effective coverage.\u003c/p\u003e \u003cp\u003eTo achieve effective refractive error services (eREC) targets, policy efforts should shift beyond short-term service expansion toward the development of coherent, system-level national refractive service delivery models. Strategic priorities include the establishment of integrated and sustainable financing mechanisms, optimisation of the eye-care workforce through appropriate task-sharing, regulation of optical markets, strengthening of health information systems, and institutionalisation of routine eREC monitoring and evaluation. Critically, aligning refractive services with the principles of Integrated People-Centred Eye Care (IPEC) within the framework of universal health coverage is essential to ensure that increased service availability translates into effective, equitable, and improved visual outcomes at population level.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eClinical trial number\u003c/h2\u003e \u003cp\u003eNot applicable.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e \u003cp\u003eEthical approval for the overarching study was obtained from the Research Ethics Board of Health (REBH), Ministry of Health, Bhutan (Ref: REBH/Approval/2023/003), and the Biomedical Research Ethics Committee (BREC) of the University of KwaZulu-Natal, South Africa (Approval No: BREC/00004482/2022). The approvals covered the development of an evidence-based model to address uncorrected refractive error in Bhutan. The present work constitutes a component of the broader model-development study; therefore, separate ethical approval was not required. As this study was conducted as a narrative review, it did not involve human participants.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication\u003c/strong\u003e \u003cp\u003eNot applicable.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eAll authors declare no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eNo funding was received for this work.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eIPS served as the study\u0026rsquo;s principal investigator. IPS, KSN and KPM jointly conceptualized the study protocol and design. IPS, KSN and NTL contributed to the review of study documents. All authors participated in the interpretation of the finding and data validation. IPS drafted the manuscript, and all authors critically reviewed, revised, and approved the final version for publication.\u003c/p\u003e\u003ch2\u003eData availability statement\u003c/h2\u003e \u003cp\u003eNo new data was generated during this study\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eMcCormick I, Mactaggart I, Bastawrous A, Burton MJ, Ramke J. 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Published 2025 Apr 22. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/bjo-2024-326643\u003c/span\u003e\u003cspan address=\"10.1136/bjo-2024-326643\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWorld Council of Optometry. \u003cem\u003eWCO Competency Framework for Optometry.\u003c/em\u003e St. Louis (MO): World Council of Optometry; 2024. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://worldcouncilofoptometry.info/wp-content/uploads/2024/02/WCO_Competency-Framework-for-Optometry.pdf\u003c/span\u003e\u003cspan address=\"https://worldcouncilofoptometry.info/wp-content/uploads/2024/02/WCO_Competency-Framework-for-Optometry.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 2026 Jan 10.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"refractive error, service delivery models, effective refractive error coverage, WHO SPECS 2030, eye health systems, narrative review","lastPublishedDoi":"10.21203/rs.3.rs-8823477/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8823477/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eDespite substantial expansion of vision screening and refraction services, effective refractive error coverage (eREC) remains suboptimal, particularly in low- and middle-income countries. This persistent gap reflects systemic shortcomings beyond diagnosis, including weaknesses in spectacle dispensing, affordability, continuity of care, and outcome monitoring. Recent global policy shifts, including adoption of effective coverage indicators and the WHO SPECS 2030 framework, have reframed refractive error (RE) correction as a health-systems performance issue rather than a purely clinical intervention. However, robust comparative evidence identifying service delivery models that most effectively and sustainably improve eREC remains limited.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA narrative review was undertaken to examine global RE and optical service delivery models through a health-systems framework. Peer-reviewed literature and authoritative policy documents published between 2000 and March 2025 were systematically synthesised. Identified models were comparatively evaluated across the refractive care continuum using six performance dimensions: access, quality, affordability and equity, continuity of care, sustainability and system integration, and scalability. In addition, models were mapped against the WHO SPECS 2030 pillars, namely services, personnel, education, cost, and surveillance.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eEight dominant eye-care service delivery models were identified: facility-based public sector services; private optical and social enterprise provision; school-based vision screening with spectacle provision; community outreach and mobile eye-camp services; tele-refraction and digitally enabled services; vision-centre- primary eye care models; public\u0026ndash;private partnership (PPP) models; and social enterprise micro-entrepreneurship models. Models emphasizing rapid scale-up of screening and refraction achieved high population reach; however, they demonstrated suboptimal performance in continuity, affordability, surveillance, and sustainability of eREC. In contrast, vision-centre and PPP models showed consistently strong performance across all six evaluative dimensions, including scalability, and exhibited the closest alignment with the WHO SPECS 2030 framework. Across all models, systemic weaknesses namely fragile optical supply chains, limited pooled financing mechanisms, inadequate follow-up systems, and absence of routine outcome monitoring were identified as the key determinants of low effective coverage.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eAchieving universal eREC constitutes primarily a health-systems challenge rather than a diagnostic limitation. The scale-up of refraction services in the absence of integrated dispensing pathways, sustainable financing mechanisms, routine surveillance, and continuity of care frameworks is unlikely to yield durable population-level impact. In contrast, vision-centre-based delivery models and PPP represent the most robust service architectures for delivering equitable, scalable, and sustainable eREC, in alignment with the WHO SPECS 2030 agenda. These models provide clear, actionable guidance for national eye-health policy formulation and programme implementation.\u003c/p\u003e","manuscriptTitle":"Global Models of Refractive Error Service Delivery: a review of design, performance, and alignment with WHO SPECS 2030","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-10 11:11:38","doi":"10.21203/rs.3.rs-8823477/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"8a4b5411-e2da-42bf-bffc-2648a68f806e","owner":[],"postedDate":"February 10th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-03T21:53:28+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-10 11:11:38","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8823477","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8823477","identity":"rs-8823477","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}