Selective Compartmental Plication in Small-Angle Convergence Insufficiency Exotropia: Surgical Outcomes and Predictive Model

Selective Compartmental Plication in Small-Angle Convergence Insufficiency Exotropia: Surgical Outcomes and Predictive Model | 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 Research Article Selective Compartmental Plication in Small-Angle Convergence Insufficiency Exotropia: Surgical Outcomes and Predictive Model Juan Ding, Pin Zhu, Liping Chen, Rui Hao, Wei Zhang, Yueping Li This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8949721/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 18 You are reading this latest preprint version Abstract Purpose This study aimed to evaluate a novel surgical approach combining lateral rectus recession (LRc) with compartmentalized inferior medial rectus plication (CIMRP) for treating small-angle (< 25 prism diopters, PD) convergence insufficiency intermittent exotropia (CI-IXT) in pediatric patients. Methods A retrospective analysis was conducted on 69 pediatric CI-IXT patients (mean age: 8.13 ± 2.46 years) who underwent LRc and CIMRP between September 2022 and January 2024 at Tianjin Eye Hospital. Outcomes including near and distance deviations, near-distance difference (NDD), control scores, stereopsis, and complications were assessed preoperatively and postoperatively at 1 day, 2 months, 6 months, and final follow-up (≥ 12 months). Results The mean LRc amount was 7.08 ± 0.48 mm (range: 6.5–7.5 mm), and the mean CIMRP amount was 3.56 ± 0.39 mm (range: 3.0–4.0 mm).Significant reductions were observed in near exo-deviation (median: −30 [− 32, − 28] PD to − 12 [− 16, − 6] PD), distance deviation (− 20 [− 20, − 18] PD to − 6 [− 10, − 1] PD), and NDD (10 [10, 10] PD to 4 [4, 6] PD; all P < 0.001). Linear regression analysis established a quantitative relationship between the amount of CIMRP and postoperative corrected NDD: Y (Postoperative corrected NDD) = 5.973 × X (amount of CIMRP in mm) − 12.48 ( P < 0.0001), indicating that each 1 mm increase in plication amount was associated with an average increase of approximately 5.97 PD in NDD correction. The surgical success rate was 88.41% at both 2 and 6 months, decreasing slightly to 81.16% at the final follow-up. The overcorrection rate peaked at 8.7% at 2 months and subsequently stabilized at 2.9%, whereas the undercorrection rate gradually increased to 15.9%. Control scores and near stereoacuity improved significantly after surgery compared with preoperative values ( P < 0.001 and P < 0.05, respectively). Conclusion LRc combined with CIMRP is an effective and safe approach for small angle CI-IXT( 10 PD based on the established dose-response model. While this targeted technique addresses convergence insufficiency with favorable outcomes, further comparative studies are needed to define its clinical role. Intermittent exotropia Convergence insufficiency Surgery Plication Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Convergence insufficiency intermittent exotropia (CI-IXT) is a clinically challenging subtype characterized by a near-distance difference (NDD) of ≥ 10 prism diopters (PD). With a prevalence of 1.2%-7.8% in pediatric IXT cases [ 1 ] , it requires specialized surgical approaches due to distinct deviation patterns at near versus distance fixation. Conventional strategies, including bilateral medial rectus resection(MRs), lateral rectus recession(LRc) combined with MR resection (R&R), and slanted LR recession, aim to correct both deviations [ 2 ] . However, for small angle CI-IXT (< 25 PD), these methods risk undercorrection or overcorrection, highlighting the need for refined techniques. The referenced anatomical studies of human and primate horizontal rectus muscles reveal a compartmentalized innervation pattern, where motor nerves bifurcate into superior and inferior divisions upon entering the proximal muscle insertion, maintaining distinct arborization zones [ 3 , 4 ] . This anatomical organization suggests the potential for targeted surgical modulation of specific muscle compartments. Based on this structural foundation, we hypothesize that selective plication of the inferior division of the medial rectus could create a mechanical restriction primarily against abduction (divergence) in the lower gaze field, which is functionally critical for convergence. When combined with lateral rectus recession, this targeted approach may generate a net biomechanical vector favoring adduction (convergence) without relying on augmenting the absolute contractile power of the medial rectus. This study evaluates the efficacy of this anatomically guided technique in pediatric CI-IXT, focusing on long-term ocular alignment stability and functional visual recovery. We specifically aim to: (1) assess the surgical outcomes of LRc combined with CIMRP; (2) establish the dose-response relationship between CIMRP amount and NDD correction; and (3) compare the safety profile of this technique with conventional approaches. Methods Patients This retrospective study analyzed clinical data from patients diagnosed with CI-IXT who underwent unilateral lateral rectus muscle recession (LRc) combined with compartmentalized inferior medial rectus plication (CIMRP) between September 2022 and January 2024 at Tianjin Eye Hospital. The study protocol was reviewed and approved by the Institutional Review Board of Tianjin Eye Hospital (Ethics Approval No. KY202224), compliant with all ethical standards for human subject research. Prior to surgical intervention, written informed consent was obtained from all participants' parents or legal guardians. Inclusion criteria were as follows: (1) CI-IXT (NDD ≥ 10 PD); (2) exodeviation measuring less than 25 PD at distance (15–25 PD range), measured by prism and alternate cover test (PACT) following monocular occlusion for 40 min; (3) wearing proper optical glasses for at least 2 months; (4) absence of paralytic, restrictive, consecutive, or congenital forms of strabismus; (5) documented symptoms related to convergence insufficiency (e.g., asthenopia, diplopia, reading difficulty) and poor control of deviation (Office-based scale Score ≥ 3 at distance or near) despite optical correction [ 5 ] . The exclusion criteria were as follows: oblique overaction/underaction, A- and V-pattern deviations; vertical deviation exceeding 5 PD; coexisting amblyopia or nystagmus; and history of strabismus surgery. Examination Protocol A comprehensive ophthalmologic and orthoptic evaluation protocol was systematically performed by a single experienced ophthalmologist. The standardized assessment included measurement of best-corrected visual acuity, cycloplegic refraction using 1% cyclopentolate hydrochloride, detailed anterior segment evaluation via slit-lamp biomicroscopy, dilated fundus examination, quantitative ocular motility assessment, and AC/A ratio calculation. For deviation measurements, PACT was rigorously performed at both distance (6 m) and near (33 cm) fixation, assessing primary position and lateral gaze positions following a standardized 40-min monocular occlusion protocol. Stereopsis was evaluated using the Random Dot 3 Stereopsis (RDS) test (Vision Assessment Corporation, USA), ensuring comprehensive binocular vision assessment. For statistical comparison of near stereopsis results, we converted the stereoscopic measurements to logarithmic values for analysis. Our standardized follow-up protocol consisted of postoperative evaluations at: 1 day, 2 months, 6 months, and a final visit (at least 1 year).The final follow-up assessments were conducted at 12 to 18 months postoperatively. Surgical Procedure and Data Collection Surgical Principle and Biomechanical Basis The CIMRP technique is founded on the compartmentalized innervation of the medial rectus muscle. By selectively placating the inferior portion, we aim to create a mechanical restriction that primarily limits abduction in the lower gaze field. This targeted restriction generates a vector force with both horizontal (adducting) and vertical (depressing) components. When combined with standard LR recession, the net effect is a preferential enhancement of convergence function without proportionally increasing muscle contractile force. This approach contrasts with traditional MR resection, which increases the muscle's absolute tension across all gaze positions.The following is a detailed steps of CIMRP technique(Fig. 1 A-D). All surgical and diagnostic procedures adhered to strict, predefined protocols established in prior studies [ 6 , 7 ] to minimize procedural variability. A single experienced surgeon (with over 25 years of pediatric strabismus surgery experience, trained in an AAPOS-approved program) performed all operations to avoid potential bias. Following a conjunctival cul-de-sac incision, LRc and CIMRP were sequentially performed. Surgical Dosage The surgical strategy was designed to fully correct the distance deviation, with the surgical dosage determined by both the distance deviation and the near-distance difference (NDD). Lateral rectus recession was performed at a standard dosage of 2 prism diopters (PD) correction per millimeter. For the compartmentalized inferior medial rectus plication, the dose-response relationship was established based on the clinical outcomes observed in this cohort. When a plication length of 1 mm was applied, approximately 3 PD of exotropic deviation was corrected. With a 3 mm plication, the mean correction achieved was about 10 PD. When performing isolated inferior plication aimed at achieving 50%-66% of the full intended effect, the corresponding correction ranged approximately between 5 and 7 PD. These results suggest a non-linear dose-response relationship. For practical surgical planning, a linear equivalent of approximately 5–7 PD per millimeter of plication was used as a working reference. This approach enables the design of individualized strategies, allowing for proportional adjustment of the plication length to achieve a desired partial correction. As an example, for a patient with a near deviation of 30 PD and a distance deviation of 20 PD, the surgical plan involved a LRc of 7 mm (correcting approximately 15 PD) and an inferior medial rectus plication of 3 mm (correcting approximately 5–7 PD). This approach aims to fully correct the distance deviation while achieving controlled orthotropia at near and limiting abduction. A comprehensive summary of the surgical parameters is presented in Table 1 . Table 1 Surgical dosage based on distance and near exodeviation Near(PD) NDD(PD) Compartmentalized inferior MR plication (mm) 25 10 3 25–30 10–15 3.5 30–35 15–20 4 Distance(PD) LRc recession (mm) 15–18 6.5 18–20 7 20–25 7.5 Outcome Definitions Postoperative successful alignment was defined as an exodeviation ≤ 10 PD or esodeviation ≤ + 5 PD in primary gaze at distance and near, and NDD ≤ 8 PD. This composite definition was selected based on clinical relevance: (1) it represents a functionally significant improvement from preoperative deviations typically exceeding 20 PD; (2) it aligns with criteria used in comparable studies [ 7 ] ^; and (3) it balances surgical goals with patient comfort and binocular function. Undercorrection was defined as postoperative exodeviation > 10 PD or NDD > 8 PD. Overcorrection was defined as postoperative esodeviation > + 5 PD [ 7 ] . Statistical Analysis Statistical analyses were performed by an independent researcher masked to clinical details to minimize interpretation bias. Analyses were conducted using GraphPad Prism software (version 8.0.2) and R (version 4.3.1). Normality of data distribution was assessed using the Shapiro-Wilk test. Continuous variables were expressed as mean ± standard deviation for normally distributed data or median (Q1, Q3) for non-normally distributed data. For longitudinal comparisons across multiple time points, the paired Friedman non-parametric test was employed, with Dunn's multiple comparison test used for post-hoc analyses. To evaluate the dose-response relationship between the amount of CIMRP and surgical outcomes, we performed correlation and regression analyses. The association between variables was first examined using Spearman rank correlation analysis. Subsequently, both simple and multiple linear regression models were constructed to predict the postoperative correction effect. The primary regression model included amount of CIMRP as the independent variable. Secondary multivariate models additionally incorporated age, preoperative AC/A ratio, and preoperative deviation magnitude as covariates to explore their potential contribution to outcome variance. Results Patient Characteristics All eligible patients treated within the study period (September 2022 to January 2024) were included, resulting in 69 participants comprising 33 males and 36 females. The mean age at surgery was 8.13 ± 2.46 years. The mean follow-up period was 12.41 ± 1.42 months. Preoperative characteristics included a mean AC/A ratio of 4.2 ± 1.8 PD/D and mean spherical equivalent refraction of -1.25 ± 1.50 D. Alignment Outcomes Table 2 presents a comparative analysis of near/distance deviations (in PD), NDD, and surgical success rates across postoperative timepoints (1 day, 2 months, 6 months, and final visit ≥ 1 year) compared to preoperative baseline. The results demonstrated significant postoperative reductions in both near and distance deviations ( P < 0.0001), with NDD decreasing from 10 (10, 10) PD preoperatively to 4 (4, 6) PD at final follow-up.While success rates remained consistently high (88.41% at both 2 and 6 months, decreasing slightly to 81.16% at final follow-up), the undercorrection rate exhibited a gradual increase from 2.90% at 2 months to 15.94% at final follow-up. In contrast, the overcorrection rate peaked at 8.70% by 2 months before stabilizing at 2.90% by the final follow-up visit. Table 2 Comparison of near/distance deviations, NDD, and success rates pre- and post-operation Timepoint Deviation (PD) (Median [Q1,Q3] NDD(PD) Success rate(%) Undercorrection rate(%) Overcorrection rate(%) Near Distance Pre-op -30 (32,-28) -20(20,-18) 10(10,10) Post-op 1d 1(0,4) 8(8,10) -6(-8,-5) Post-op 2m -4(-8,-2) -2(-4,0) 2(2,4) 61/69(88.41%) 2/69(2.90%) 6/69(8.70%) Post-op 6m -8(-12,-4) -4(-8,0) 4(2,4) 61/69(88.41%) 5/69(7.25%) 3/69(4.35%) Final visit -12(-16,-6) -6(-10,-1) 4(4,6) 56/69(81.16%) 11/69(15.94%) 2/69(2.90%) P < 0.001 < 0.001 < 0.001 PD: prism diopters; NDD: near–distance difference; Q1: 25th percentile; Q3: 75th percentile. Further analysis of deviation measurements in 69 patients with CI-IXT before and after surgical intervention, comparing near and distance fixation across multiple postoperative intervals, is shown in Fig. 2 . The paired Friedman test followed by Dunn's multiple comparisons revealed statistically significant reductions in deviations for both near and distance fixation, with notable changes occurring early postoperatively (1 day) and further adjustments observed over subsequent follow-ups. NDD As shown in Fig. 2 B, NDD demonstrated significant improvement following surgical intervention. Comparative analysis revealed statistically significant reductions in NDD at all postoperative time points compared to preoperative measurements (P 0.05). Dose-Response Relationship and Regression Analysis Dose-Response Relationship and Regression Analysis Spearman rank correlation analysis indicated a significant positive correlation between the amount of CIMRP and postoperative corrected NDD (ρ = 0.452, P = 2.332×10⁻⁴), as well as with corrected near deviation (ρ = 0.321, P = 0.007). No significant correlation was observed between the amount of CIMRP and preoperative distance deviation (ρ = 0.102, P = 0.410). Notably, the amount of LRc showed no significant correlation with corrected NDD or corrected deviations at near and distance (all P > 0.05). Simple linear regression yielded the predictive model(Fig. 3 ): Corrected NDD = 5.973 × CIMRP (mm) – 12.48 The slope of 5.973 (95% CI: 3.098–8.848, P < 0.0001) indicates that each 1 mm increase in CIMRP corresponds to an average increase of approximately 5.97 PD in corrected NDD. While the model explained 20.42% of the variance in outcomes (R² = 0.2042), this is clinically meaningful given the multifactorial nature of surgical outcomes in strabismus. Multivariate regression incorporating age, preoperative AC/A ratio, and preoperative deviation improved explanatory power to R² = 0.356 ( P < 0.001), with CIMRP amount (β = 4.872, P = 0.002) and preoperative AC/A ratio (β = 0.891, P = 0.032) remaining significant predictors. Clinical observation confirmed a dose–response relationship: as CIMRP increased from 2.0 mm to 4.0 mm, corrected NDD rose from 0 PD to 15 PD, with marked improvement when plication reached ≥ 3.5 mm. Based on the regression equation, a minimum CIMRP of 2.09 mm is required to initiate NDD correction (threshold: 12.48/5.973). To achieve corrections of 10 PD and 15 PD, plication amounts of approximately 3.76 mm and 4.60 mm are needed, exceeding the original surgical design by 0.76 mm and 1.20 mm, respectively. Sensitivity analysis using an alternative NDD indicator supported these findings (slope = 5.258, P < 0.0001, R² = 0.2886), further validating CIMRP as a consistent predictor of correction efficacy. Functional Outcomes Control Score We assessed exotropia control using the Office Control Score system [ 5 ] . Preoperative median control scores were 2 (1, 3.25) points for near fixation and 4 (2, 5) points for distance fixation, resulting in a total combined score of 5 (5, 8) points. Postoperatively, scores improved significantly to 0 (0, 1) at near and 1 (0, 2) at distance (total score 1 (0, 3); P < 0.001, Friedman test,Fig. 4 ). Stereopsis Near stereopsis was assessed using logarithmically transformed binocular disparity values. Preoperative median near stereoacuity (RDS) was 1.40 (1.10–1.60). At final follow-up, these values measured 1.30 (1.10–1.51), representing a statistically significant improvement (P < 0.05). Clinically meaningful improvement (defined as transition from no stereopsis to measurable stereopsis, or improvement by ≥ 0.3 log units) was observed in 42/69 patients (60.9%). Complications Postoperative complications were evaluated in all 69 patients. Transient lateral gaze incomitance was observed in all patients on postoperative day 1, with median abduction limitation of -2 (-2, -1) PD in the operated eye. This restriction resolved completely by 2 months in all cases. The degree of initial abduction limitation correlated moderately with the amount of CIMRP (ρ = 0.387, P = 0.001). Final overcorrection occurred in 2.90% (2/69) of patients, while undercorrection was observed in 15.94% (11/69), mainly manifesting as residual exodeviation > 10 PD or NDD > 8 PD. No serious complications such as scleral perforation, muscle slippage, anterior segment ischemia, rotational diplopia, or pattern strabismus occurred during the study period. Discussion Surgical management of CI-IXT has advanced significantly, with MRs, LRc, and R&R procedures serving as therapeutic mainstays. However, these conventional approaches are limited by high recurrence rates, overcorrection risks, and suboptimal long-term stability, which has continued to drive surgical innovation. The combined LRc and CIMRP technique presented in this study represents a refined and anatomically targeted alternative, particularly suitable for small-angle CI-IXT (< 25 PD), by integrating established surgical principles with precision modifications. Surgical Mechanism and Physiological Rationale The CIMRP technique embodies a paradigm shift in the surgical approach to CI-IXT. Unlike traditional MR resection, which increases global muscle tension, CIMRP creates a selective mechanical restriction localized to the inferior portion of the MR. This strategy is grounded in the well-established compartmentalized innervation of extraocular muscles, where superior and inferior divisions are separately innervated and may subserve distinct functional roles [ 3 , 4 ] . As the inferior MR is biomechanically pivotal for convergence—often engaged during downgaze associated with near visual tasks—targeted intervention in this region allows for more physiological modulation of convergence function. Biomechanically, CIMRP is postulated to generate a force vector with a dominant horizontal (adducting) component. When combined with a calibrated LRc, the net effect preferentially enhances convergence while minimizing disruption to primary gaze alignment. This targeted mechanism likely underlies the significant correction of NDD observed in our cohort, where the median NDD improved from 10 PD preoperatively to 4 PD postoperatively. Comparative Efficacy and Technical Advantages The defining characteristic of CI-IXT is a clinically significant NDD of ≥ 10 PD, making the simultaneous correction of both distance deviation and NDD essential for optimal outcomes. Existing techniques achieve this balance with varying success and limitations: Unilateral LR Recession with MR Resection : This approach has demonstrated promising short-term results, with one study reporting 100% success in reducing near deviation and NDD [ 8 ] . However, efficacy is constrained by small sample sizes and limited follow-up, with long-term success rates dropping substantially (e.g., 42.9% at 26.6 months) [ 9 ] . Slanted Bilateral LR Recession (S-BLRc): Leveraging compartmentalized anatomy, S-BLRc has emerged as a preferred technique, showing 80–90% short-term success and sustained benefits in longer-term studies (57-89.7% success) [ 10 – 12 ] . However, it requires complex, separate calculations for the superior and inferior LR poles and carries a notable overcorrection risk (reported up to 16.9%) [ 13 ] . Our Combined LRc + CIMRP Technique : In our cohort, this approach achieved an 81.16% success rate at ≥ 12 months, with excellent stability (no significant NDD change after 2 months) and a minimal complication profile (2.90% overcorrection, 15.94% undercorrection). These outcomes compare favorably with or exceed those reported for S-BLRc and R&R, particularly in achieving a balanced near-distance correction [ 10 , 12 , 14 ] . The advantages of CIMRP stem from its precise anatomical targeting : Selective Functional Augmentation : The success of CIMRP stems from its alignment with the well-documented non-overlapping zonal innervation of extraocular muscles [ 15 , 16 ] .It directly tightens the functionally critical inferior MR, the key muscle compartment for convergence. Enhanced Safety : Unlike traditional MR resection—which is associated with transient distance esotropia [ 17 , 18 ] —and S-BLRc—which carries an overcorrection risk of up to 16.9% [ 13 ] —the plication technique preserves the anterior ciliary arteries, markedly reducing the risk of anterior segment ischemia compared to resection, while also achieving a very low overcorrection rate. Theoretical Reversibility and Stability : The procedure is theoretically reversible and, by preserving the original MR insertion, may reduce risks of secondary deviation, contributing to postoperative stability. Dose-Response Relationship and Refined Surgical Planning The linear regression model (Corrected NDD = 5.973 × CIMRP (mm) – 12.48) establishes a critical, quantifiable dose-response relationship for surgical planning. Each additional millimeter of plication yielded a predictable correction of approximately 6 PD in NDD. While the model's R² of 0.2042 indicates that plication amount alone explains approximately 20% of outcome variance—a clinically meaningful contribution for a single parameter given the multifactorial nature of strabismus surgery—the explanatory power increased to 35.6% (R² = 0.356) in a multivariate model incorporating preoperative AC/A ratio, age, and preoperative deviation. This finding underscores the importance of patient-specific factors in determining surgical success. Notably, the multivariate model was not used as the primary dosing guide due to its complexity. Instead, we prioritized the simple linear model based solely on CIMRP amount, as it offers the most direct and reproducible guidance for surgeons adopting this novel technique. Future studies with larger, more diverse cohorts may validate a weighted nomogram that integrates AC/A ratio and age, enabling more personalized surgical planning. The robustness of the dose-response relationship was further confirmed by sensitivity analysis using an alternative NDD indicator, which yielded a similar slope (5.258, P < 0.0001) and supported CIMRP as a consistent predictor of correction efficacy. Our integrated dosing protocol—1 mm of LR recession per 2 PD of distance deviation, paired with a CIMRP amount calibrated to the preoperative NDD—provides a physiologically grounded and precise surgical strategy. Based on the regression model, we recommend a minimum CIMRP of 3.5 mm for patients with preoperative NDD > 10 PD to achieve optimal convergence enhancement. For the challenging subgroup of small-angle CI-IXT (14–20 PD), where R&R has historically outperformed unilateral LR recession (58% vs. 34% success) [ 19 , 20 ] , our technique builds upon this foundation to deliver a higher sustained success rate (81.16%) with lower overcorrection. Functional Outcomes and Safety Profile The significant improvement in control scores (preoperative median: 2 at near, 4 at distance; postoperative: 0 at near, 1 at distance) confirms enhanced fusional stability following surgery. Although the median improvement in stereoacuity was modest (0.1 log units), the fact that 60.9% of patients achieved clinically meaningful improvement is encouraging for functional visual rehabilitation. The safety profile of CIMRP is favorable. Transient abduction limitation was observed in all patients on postoperative day 1 (median: −2 PD), but resolved completely within 2 months in all cases. The degree of initial limitation correlated moderately with CIMRP amount (ρ = 0.387, P = 0.001), suggesting a predictable and self-limited postoperative course. Notably, there were no serious complications such as anterior segment ischemia, scleral perforation, or pattern strabismus. Limitations and Future Directions This study represents an exploratory investigation of a novel surgical technique. We acknowledge the inherent limitations of its retrospective, single-center design and explicitly position this work as providing preliminary evidence to inform future prospective randomized controlled trials. The sample size of 69 patients was determined based on feasibility considerations; post hoc power analysis confirmed 80% power (α = 0.05) to detect a moderate effect size (f = 0.35) in the primary outcome measures, supporting the adequacy of the cohort for detecting clinically meaningful differences. Additional limitations include the mean follow-up of 12.4 months, which, while adequate for assessing initial stability, is insufficient to evaluate long-term drift—a known challenge in strabismus surgery. The absence of a direct control group (e.g., S-BLRc or R&R) precludes definitive comparative conclusions. Future research should prioritize: (1) prospective, randomized controlled trials directly comparing CIMRP + LRc with established techniques; (2) long-term follow-up studies (3–5 years) to assess stability; (3) multicenter studies to validate generalizability; and (4) investigations into additional anatomical and biomechanical predictors of surgical outcomes, potentially leading to a weighted nomogram for personalized surgical planning. Conclusion In summary, lateral rectus recession combined with compartmentalized inferior medial rectus plication (LRc+CIMRP) offers a safe and effective surgical approach for small angle(< 25PD) convergence insufficiency intermittent exotropia (CI-IXT). This technique demonstrates strong near-distance disparity (NDD) correction, stable alignment outcomes, and minimal complications. Based on the established dose-response model, we recommend CIMRP of ≥ 3.5 mm for patients with preoperative NDD > 10 PD to achieve optimal convergence enhancement. By selectively targeting the pathophysiological mechanism underlying CI-IXT, this approach represents an advance in the surgical armamentarium, though further comparative studies are warranted to precisely define its clinical role. Declarations Conflicts of interests The authors declared that they have no conflicts of interest to this work. Ethics approval and consent to participate All methods were performed by following per under the relevant guidelines and regulations. Ethics approval for this research was granted by the Medical Ethics Committee of the Tianjin Eye Hospital(KY20224). Funding The study was supported by Science and Technology Project of Tianjin Health Commission (TJWJ2025MS036); Nankai University Ophthalmology Institute Open Fund(NKYKK202201), Nankai University Optometry&Vision Science Institute Open Fund ( NKSGY202405)Tianjin Key Medical Discipline (Specialty) Construction Project(NO.TJYXZDXK-016A). Author Contributions All authors contributed to the study conception and design. Material preparation and data collection were performed by JD,PZ,YPL. All authors recruited and saw patients involved in this study. Data analysis was performed by JD and YPL; all authors interpreted the study data. The first draft of the manuscript was written by JD, with support from YPL, and all authors commented on pre-final versions of the manuscript. All authors read and approved the final manuscript. References Kushner BJ, Morton GV. Distance/near differences in intermittent exotropia. Arch Ophthalmol. 1998;116(4):478–86. Hwang JM. How to better treat patients with intermittent exotropia: a review of surgical treatment of intermittent exotropia. Korean J Ophthalmol. 2022;36(6):550–64. Peng M, Poukens V, da Silva Costa RM, Yoo L, Tychsen L, Demer JL. Compartmentalized innervation of primate lateral rectus muscle. 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Differential lateral rectus compartmental contraction during ocular counter-rolling. Invest Ophthalmol Vis Sci. 2014;55(8):4847–56. Hermann JS. Surgical therapy for convergence insufficiency. J Pediatr Ophthalmol Strabismus. 1981;18(1):28–31. von Noorden GK. Resection of both medial rectus muscles in organic convergence insufficiency. Am J Ophthalmol. 1976;81(2):223–6. Menon V, Singla MA, Saxena R, Phuljhele S. Comparative study of unilateral and bilateral surgery in moderate exotropia. J Pediatr Ophthalmol Strabismus. 2010;47(5):288–91. Almahmoudi FH, Al Shamrani M, Khan AM. The use of one muscle recession for horizontal strabismus. Saudi J Ophthalmol. 2018;32(3):200–3. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8949721","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":607400573,"identity":"6a95d292-d558-48c7-b9df-3edecda8f136","order_by":0,"name":"Juan Ding","email":"","orcid":"","institution":"Tianjin Eye Hospital","correspondingAuthor":false,"prefix":"","firstName":"Juan","middleName":"","lastName":"Ding","suffix":""},{"id":607400574,"identity":"a276877e-fa42-4588-a3a7-24d399185789","order_by":1,"name":"Pin Zhu","email":"","orcid":"","institution":"Tianjin Eye Hospital","correspondingAuthor":false,"prefix":"","firstName":"Pin","middleName":"","lastName":"Zhu","suffix":""},{"id":607400577,"identity":"e266e829-6777-4d8f-a699-8d186fe70b62","order_by":2,"name":"Liping Chen","email":"","orcid":"","institution":"Tianjin Eye Hospital","correspondingAuthor":false,"prefix":"","firstName":"Liping","middleName":"","lastName":"Chen","suffix":""},{"id":607400579,"identity":"e010abc5-b631-41f7-a3b7-3788ea508402","order_by":3,"name":"Rui Hao","email":"","orcid":"","institution":"Tianjin Eye Hospital","correspondingAuthor":false,"prefix":"","firstName":"Rui","middleName":"","lastName":"Hao","suffix":""},{"id":607400580,"identity":"fbde62ce-8eb5-49ca-9158-922631e00f41","order_by":4,"name":"Wei Zhang","email":"","orcid":"","institution":"Tianjin Eye Hospital","correspondingAuthor":false,"prefix":"","firstName":"Wei","middleName":"","lastName":"Zhang","suffix":""},{"id":607400582,"identity":"1739144f-1574-4672-9914-c880834353e6","order_by":5,"name":"Yueping Li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7ElEQVRIiWNgGAWjYBACPijNw8DAfIDhgQERWtgQWtgSGBJI0QLSZcCQQIzD2Nibj0nzVNyRMedf8/FDQsHhxO0MzA8f3cCnhedYmjTPmWc8ljPebpZIMDicuLOBzdg4B58WiRwzad62wzwGN85uAGvZcICHTRqvFvn336R5/4G0nHn8gzgtEkAFvA1ALed72Ii0hSfN2HLOsWdAW9jMLBIM0o03HCbgF372ww9vvKm5Y29w/vDjGx/+WMtuON788DE+LUDAIsHAcICBQSIBxGkGpgL8ykGA+QNYC/8BEKeOsPpRMApGwSgYcQAAW7xPJFHPdikAAAAASUVORK5CYII=","orcid":"","institution":"Tianjin Eye Hospital","correspondingAuthor":true,"prefix":"","firstName":"Yueping","middleName":"","lastName":"Li","suffix":""}],"badges":[],"createdAt":"2026-02-23 17:54:34","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8949721/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8949721/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104998309,"identity":"7f6d4169-178c-4642-b8de-5cfc15f0cdb8","added_by":"auto","created_at":"2026-03-19 16:26:19","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":3176445,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eProcedure of compartmentalized inferior medial rectus plication(CIMRP)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e(A) Muscle Penetration: A 6-0 polyglactin suture was passed through two-thirds of the medial rectus thickness, 3–4 mm posterior to insertion.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e(B) Locking Bite: A locking bite was placed at the inferior one-third muscle margin to secure the suture.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e(C) Scleral Fixation: The needle was reintroduced into sclera 0.5 mm anterior to the original insertion midpoint, exiting inferiorly.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e(D) Muscle Advancement: Sutures were tied under direct vision, advancing and selectively shortening the inferior muscle portion.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8949721/v1/7d4950991e704ac128f8109a.png"},{"id":104998268,"identity":"9ffcb7bf-cc60-49ce-bfed-c92434d14036","added_by":"auto","created_at":"2026-03-19 16:26:02","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":47196,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDeviation and NDD in 69 patients with CI-IXT before and after surgical intervention.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e(A) Near fixation data; (B) Distance fixation data. P\u0026lt;0.05 vs. pre-op; †P\u0026lt;0.05 vs. 1 day; ‡P\u0026lt;0.05 vs. 2 months; §P\u0026lt;0.05 vs. 6 months; #P\u0026lt;0.05 vs. final visit.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8949721/v1/0af8d70b0ce753dad23ffe1b.png"},{"id":104998260,"identity":"ee1f33fc-6ad3-4dd4-84f2-dfbc0fa28f04","added_by":"auto","created_at":"2026-03-19 16:26:00","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":70795,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDose-Response Relationship between Amount of CIMRP and Postoperative Corrected NDD\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8949721/v1/cc1a5f6ae1a7f9bee763445b.png"},{"id":104998270,"identity":"e99ed9e1-c45e-412d-a7d1-fe92498714b5","added_by":"auto","created_at":"2026-03-19 16:26:03","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":56986,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eComparison of control score between preoperative baseline and different postoperative time points.\u003c/strong\u003e\u003cem\u003e\u003cstrong\u003e P\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e\u0026lt;0.001, Friedman test.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8949721/v1/3035fe6165b3bb1d5ef75551.png"},{"id":105035812,"identity":"1d14c4de-e7c0-4541-a903-b6666ee0b20c","added_by":"auto","created_at":"2026-03-20 07:26:40","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4278383,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8949721/v1/2d0f5c3e-9e06-4875-afb9-65ebd4f28170.pdf"},{"id":104998274,"identity":"bfee6491-82b9-4716-9540-c372fc873de2","added_by":"auto","created_at":"2026-03-19 16:26:04","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":12082,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementaryfile.docx","url":"https://assets-eu.researchsquare.com/files/rs-8949721/v1/203bc5364c29455567da68ff.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Selective Compartmental Plication in Small-Angle Convergence Insufficiency Exotropia: Surgical Outcomes and Predictive Model","fulltext":[{"header":"Introduction","content":"\u003cp\u003eConvergence insufficiency intermittent exotropia (CI-IXT) is a clinically challenging subtype characterized by a near-distance difference (NDD) of \u0026ge;\u0026thinsp;10 prism diopters (PD). With a prevalence of 1.2%-7.8% in pediatric IXT cases \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e, it requires specialized surgical approaches due to distinct deviation patterns at near versus distance fixation. Conventional strategies, including bilateral medial rectus resection(MRs), lateral rectus recession(LRc) combined with MR resection (R\u0026amp;R), and slanted LR recession, aim to correct both deviations\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. However, for small angle CI-IXT (\u0026lt;\u0026thinsp;25 PD), these methods risk undercorrection or overcorrection, highlighting the need for refined techniques.\u003c/p\u003e \u003cp\u003eThe referenced anatomical studies of human and primate horizontal rectus muscles reveal a compartmentalized innervation pattern, where motor nerves bifurcate into superior and inferior divisions upon entering the proximal muscle insertion, maintaining distinct arborization zones \u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. This anatomical organization suggests the potential for targeted surgical modulation of specific muscle compartments. Based on this structural foundation, we hypothesize that selective plication of the inferior division of the medial rectus could create a mechanical restriction primarily against abduction (divergence) in the lower gaze field, which is functionally critical for convergence. When combined with lateral rectus recession, this targeted approach may generate a net biomechanical vector favoring adduction (convergence) without relying on augmenting the absolute contractile power of the medial rectus.\u003c/p\u003e \u003cp\u003eThis study evaluates the efficacy of this anatomically guided technique in pediatric CI-IXT, focusing on long-term ocular alignment stability and functional visual recovery. We specifically aim to: (1) assess the surgical outcomes of LRc combined with CIMRP; (2) establish the dose-response relationship between CIMRP amount and NDD correction; and (3) compare the safety profile of this technique with conventional approaches.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n\u003ch2\u003ePatients\u003c/h2\u003e\n\u003cp\u003eThis retrospective study analyzed clinical data from patients diagnosed with CI-IXT who underwent unilateral lateral rectus muscle recession (LRc) combined with compartmentalized inferior medial rectus plication (CIMRP) between September 2022 and January 2024 at Tianjin Eye Hospital. The study protocol was reviewed and approved by the Institutional Review Board of Tianjin Eye Hospital (Ethics Approval No. KY202224), compliant with all ethical standards for human subject research. Prior to surgical intervention, written informed consent was obtained from all participants' parents or legal guardians.\u003c/p\u003e\n\u003cp\u003eInclusion criteria were as follows: (1) CI-IXT (NDD\u0026thinsp;\u0026ge;\u0026thinsp;10 PD); (2) exodeviation measuring less than 25 PD at distance (15\u0026ndash;25 PD range), measured by prism and alternate cover test (PACT) following monocular occlusion for 40 min; (3) wearing proper optical glasses for at least 2 months; (4) absence of paralytic, restrictive, consecutive, or congenital forms of strabismus; (5) documented symptoms related to convergence insufficiency (e.g., asthenopia, diplopia, reading difficulty) and poor control of deviation (Office-based scale Score\u0026thinsp;\u0026ge;\u0026thinsp;3 at distance or near) despite optical correction \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e .\u003c/p\u003e\n\u003cp\u003eThe exclusion criteria were as follows: oblique overaction/underaction, A- and V-pattern deviations; vertical deviation exceeding 5 PD; coexisting amblyopia or nystagmus; and history of strabismus surgery.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eExamination Protocol\u003c/h3\u003e\n\u003cp\u003eA comprehensive ophthalmologic and orthoptic evaluation protocol was systematically performed by a single experienced ophthalmologist. The standardized assessment included measurement of best-corrected visual acuity, cycloplegic refraction using 1% cyclopentolate hydrochloride, detailed anterior segment evaluation via slit-lamp biomicroscopy, dilated fundus examination, quantitative ocular motility assessment, and AC/A ratio calculation. For deviation measurements, PACT was rigorously performed at both distance (6 m) and near (33 cm) fixation, assessing primary position and lateral gaze positions following a standardized 40-min monocular occlusion protocol. Stereopsis was evaluated using the Random Dot 3 Stereopsis (RDS) test (Vision Assessment Corporation, USA), ensuring comprehensive binocular vision assessment. For statistical comparison of near stereopsis results, we converted the stereoscopic measurements to logarithmic values for analysis.\u003c/p\u003e\n\u003cp\u003eOur standardized follow-up protocol consisted of postoperative evaluations at: 1 day, 2 months, 6 months, and a final visit (at least 1 year).The final follow-up assessments were conducted at 12 to 18 months postoperatively.\u003c/p\u003e\n\u003ch3\u003eSurgical Procedure and Data Collection\u003c/h3\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n\u003ch2\u003eSurgical Principle and Biomechanical Basis\u003c/h2\u003e\n\u003cp\u003eThe CIMRP technique is founded on the compartmentalized innervation of the medial rectus muscle. By selectively placating the inferior portion, we aim to create a mechanical restriction that primarily limits abduction in the lower gaze field. This targeted restriction generates a vector force with both horizontal (adducting) and vertical (depressing) components. When combined with standard LR recession, the net effect is a preferential enhancement of convergence function without proportionally increasing muscle contractile force. This approach contrasts with traditional MR resection, which increases the muscle's absolute tension across all gaze positions.The following is a detailed steps of CIMRP technique(Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eA-D).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll surgical and diagnostic procedures adhered to strict, predefined protocols established in prior studies \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e to minimize procedural variability. A single experienced surgeon (with over 25 years of pediatric strabismus surgery experience, trained in an AAPOS-approved program) performed all operations to avoid potential bias. Following a conjunctival cul-de-sac incision, LRc and CIMRP were sequentially performed.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eSurgical Dosage\u003c/h3\u003e\n\u003cp\u003eThe surgical strategy was designed to fully correct the distance deviation, with the surgical dosage determined by both the distance deviation and the near-distance difference (NDD). Lateral rectus recession was performed at a standard dosage of 2 prism diopters (PD) correction per millimeter. For the compartmentalized inferior medial rectus plication, the dose-response relationship was established based on the clinical outcomes observed in this cohort. When a plication length of 1 mm was applied, approximately 3 PD of exotropic deviation was corrected. With a 3 mm plication, the mean correction achieved was about 10 PD. When performing isolated inferior plication aimed at achieving 50%-66% of the full intended effect, the corresponding correction ranged approximately between 5 and 7 PD. These results suggest a non-linear dose-response relationship. For practical surgical planning, a linear equivalent of approximately 5\u0026ndash;7 PD per millimeter of plication was used as a working reference. This approach enables the design of individualized strategies, allowing for proportional adjustment of the plication length to achieve a desired partial correction.\u003c/p\u003e\n\u003cp\u003eAs an example, for a patient with a near deviation of 30 PD and a distance deviation of 20 PD, the surgical plan involved a LRc of 7 mm (correcting approximately 15 PD) and an inferior medial rectus plication of 3 mm (correcting approximately 5\u0026ndash;7 PD). This approach aims to fully correct the distance deviation while achieving controlled orthotropia at near and limiting abduction. A comprehensive summary of the surgical parameters is presented in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eSurgical dosage based on distance and near exodeviation\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eNear(PD)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eNDD(PD)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eCompartmentalized inferior MR plication (mm)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e25\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e25\u0026ndash;30\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10\u0026ndash;15\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e3.5\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e30\u0026ndash;35\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e15\u0026ndash;20\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Taba\" border=\"1\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eDistance(PD)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLRc recession (mm)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e15\u0026ndash;18\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6.5\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e18\u0026ndash;20\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e7\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e20\u0026ndash;25\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e7.5\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n\u003ch2\u003eOutcome Definitions\u003c/h2\u003e\n\u003cp\u003ePostoperative successful alignment was defined as an exodeviation\u0026thinsp;\u0026le;\u0026thinsp;10 PD or esodeviation\u0026thinsp;\u0026le;\u0026thinsp;+\u0026thinsp;5 PD in primary gaze at distance and near, and NDD\u0026thinsp;\u0026le;\u0026thinsp;8 PD. This composite definition was selected based on clinical relevance: (1) it represents a functionally significant improvement from preoperative deviations typically exceeding 20 PD; (2) it aligns with criteria used in comparable studies \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e^; and (3) it balances surgical goals with patient comfort and binocular function. Undercorrection was defined as postoperative exodeviation\u0026thinsp;\u0026gt;\u0026thinsp;10 PD or NDD\u0026thinsp;\u0026gt;\u0026thinsp;8 PD. Overcorrection was defined as postoperative esodeviation\u0026thinsp;\u0026gt;\u0026thinsp;+\u0026thinsp;5 PD \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\n\u003cp\u003eStatistical analyses were performed by an independent researcher masked to clinical details to minimize interpretation bias. Analyses were conducted using GraphPad Prism software (version 8.0.2) and R (version 4.3.1). Normality of data distribution was assessed using the Shapiro-Wilk test. Continuous variables were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation for normally distributed data or median (Q1, Q3) for non-normally distributed data. For longitudinal comparisons across multiple time points, the paired Friedman non-parametric test was employed, with Dunn's multiple comparison test used for post-hoc analyses.\u003c/p\u003e\n\u003cp\u003eTo evaluate the dose-response relationship between the amount of CIMRP and surgical outcomes, we performed correlation and regression analyses. The association between variables was first examined using Spearman rank correlation analysis. Subsequently, both simple and multiple linear regression models were constructed to predict the postoperative correction effect. The primary regression model included amount of CIMRP as the independent variable. Secondary multivariate models additionally incorporated age, preoperative AC/A ratio, and preoperative deviation magnitude as covariates to explore their potential contribution to outcome variance.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n\u003ch2\u003ePatient Characteristics\u003c/h2\u003e\n\u003cp\u003eAll eligible patients treated within the study period (September 2022 to January 2024) were included, resulting in 69 participants comprising 33 males and 36 females. The mean age at surgery was 8.13\u0026thinsp;\u0026plusmn;\u0026thinsp;2.46 years. The mean follow-up period was 12.41\u0026thinsp;\u0026plusmn;\u0026thinsp;1.42 months. Preoperative characteristics included a mean AC/A ratio of 4.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 PD/D and mean spherical equivalent refraction of -1.25\u0026thinsp;\u0026plusmn;\u0026thinsp;1.50 D.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\n\u003ch2\u003eAlignment Outcomes\u003c/h2\u003e\n\u003cp\u003eTable\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e presents a comparative analysis of near/distance deviations (in PD), NDD, and surgical success rates across postoperative timepoints (1 day, 2 months, 6 months, and final visit\u0026thinsp;\u0026ge;\u0026thinsp;1 year) compared to preoperative baseline. The results demonstrated significant postoperative reductions in both near and distance deviations (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001), with NDD decreasing from 10 (10, 10) PD preoperatively to 4 (4, 6) PD at final follow-up.While success rates remained consistently high (88.41% at both 2 and 6 months, decreasing slightly to 81.16% at final follow-up), the undercorrection rate exhibited a gradual increase from 2.90% at 2 months to 15.94% at final follow-up. In contrast, the overcorrection rate peaked at 8.70% by 2 months before stabilizing at 2.90% by the final follow-up visit.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eComparison of near/distance deviations, NDD, and success rates pre- and post-operation\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eTimepoint\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eDeviation (PD) (Median [Q1,Q3]\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eNDD(PD)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eSuccess rate(%)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eUndercorrection rate(%)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eOvercorrection rate(%)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eNear\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eDistance\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-op\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-30 (32,-28)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-20(20,-18)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10(10,10)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePost-op 1d\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1(0,4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e8(8,10)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-6(-8,-5)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePost-op 2m\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-4(-8,-2)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-2(-4,0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2(2,4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e61/69(88.41%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e2/69(2.90%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e6/69(8.70%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePost-op 6m\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-8(-12,-4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-4(-8,0)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4(2,4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e61/69(88.41%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e5/69(7.25%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e3/69(4.35%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eFinal visit\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-12(-16,-6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e-6(-10,-1)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4(4,6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e56/69(81.16%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e11/69(15.94%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e2/69(2.90%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003ePD: prism diopters; NDD: near\u0026ndash;distance difference; Q1: 25th percentile; Q3: 75th percentile.\u003c/p\u003e\n\u003cp\u003eFurther analysis of deviation measurements in 69 patients with CI-IXT before and after surgical intervention, comparing near and distance fixation across multiple postoperative intervals, is shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. The paired Friedman test followed by Dunn's multiple comparisons revealed statistically significant reductions in deviations for both near and distance fixation, with notable changes occurring early postoperatively (1 day) and further adjustments observed over subsequent follow-ups.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\n\u003ch2\u003eNDD\u003c/h2\u003e\n\u003cp\u003eAs shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003eB, NDD demonstrated significant improvement following surgical intervention. Comparative analysis revealed statistically significant reductions in NDD at all postoperative time points compared to preoperative measurements (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The therapeutic effect remained stable during later follow-up periods, with no significant differences between 2-month, 6-month, and final visit assessments (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\n\u003ch2\u003eDose-Response Relationship and Regression Analysis\u003c/h2\u003e\n\u003cdiv id=\"Sec15\" class=\"Section3\"\u003e\n\u003ch2\u003eDose-Response Relationship and Regression Analysis\u003c/h2\u003e\n\u003cp\u003eSpearman rank correlation analysis indicated a significant positive correlation between the amount of CIMRP and postoperative corrected NDD (\u0026rho;\u0026thinsp;=\u0026thinsp;0.452, P\u0026thinsp;=\u0026thinsp;2.332\u0026times;10⁻⁴), as well as with corrected near deviation (\u0026rho;\u0026thinsp;=\u0026thinsp;0.321, P\u0026thinsp;=\u0026thinsp;0.007). No significant correlation was observed between the amount of CIMRP and preoperative distance deviation (\u0026rho;\u0026thinsp;=\u0026thinsp;0.102, P\u0026thinsp;=\u0026thinsp;0.410). Notably, the amount of LRc showed no significant correlation with corrected NDD or corrected deviations at near and distance (all \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\n\u003ch2\u003eSimple linear regression yielded the predictive model(Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e):\u003c/h2\u003e\n\u003cdiv id=\"Sec17\" class=\"Section3\"\u003e\n\u003ch2\u003eCorrected NDD\u0026thinsp;=\u0026thinsp;5.973 \u0026times; CIMRP (mm) \u0026ndash; 12.48\u003c/h2\u003e\n\u003cp\u003eThe slope of 5.973 (95% CI: 3.098\u0026ndash;8.848, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) indicates that each 1 mm increase in CIMRP corresponds to an average increase of approximately 5.97 PD in corrected NDD. While the model explained 20.42% of the variance in outcomes (R\u0026sup2; = 0.2042), this is clinically meaningful given the multifactorial nature of surgical outcomes in strabismus. Multivariate regression incorporating age, preoperative AC/A ratio, and preoperative deviation improved explanatory power to R\u0026sup2; = 0.356 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with CIMRP amount (\u0026beta;\u0026thinsp;=\u0026thinsp;4.872, P\u0026thinsp;=\u0026thinsp;0.002) and preoperative AC/A ratio (\u0026beta;\u0026thinsp;=\u0026thinsp;0.891, P\u0026thinsp;=\u0026thinsp;0.032) remaining significant predictors.\u003c/p\u003e\n\u003cp\u003eClinical observation confirmed a dose\u0026ndash;response relationship: as CIMRP increased from 2.0 mm to 4.0 mm, corrected NDD rose from 0 PD to 15 PD, with marked improvement when plication reached\u0026thinsp;\u0026ge;\u0026thinsp;3.5 mm. Based on the regression equation, a minimum CIMRP of 2.09 mm is required to initiate NDD correction (threshold: 12.48/5.973). To achieve corrections of 10 PD and 15 PD, plication amounts of approximately 3.76 mm and 4.60 mm are needed, exceeding the original surgical design by 0.76 mm and 1.20 mm, respectively.\u003c/p\u003e\n\u003cp\u003eSensitivity analysis using an alternative NDD indicator supported these findings (slope\u0026thinsp;=\u0026thinsp;5.258, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001, R\u0026sup2; = 0.2886), further validating CIMRP as a consistent predictor of correction efficacy.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\n\u003ch2\u003eFunctional Outcomes\u003c/h2\u003e\n\u003cp\u003e\u003cstrong\u003eControl Score\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe assessed exotropia control using the Office Control Score system\u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e. Preoperative median control scores were 2 (1, 3.25) points for near fixation and 4 (2, 5) points for distance fixation, resulting in a total combined score of 5 (5, 8) points. Postoperatively, scores improved significantly to 0 (0, 1) at near and 1 (0, 2) at distance (total score 1 (0, 3); \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Friedman test,Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStereopsis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNear stereopsis was assessed using logarithmically transformed binocular disparity values. Preoperative median near stereoacuity (RDS) was 1.40 (1.10\u0026ndash;1.60). At final follow-up, these values measured 1.30 (1.10\u0026ndash;1.51), representing a statistically significant improvement (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Clinically meaningful improvement (defined as transition from no stereopsis to measurable stereopsis, or improvement by \u0026ge;\u0026thinsp;0.3 log units) was observed in 42/69 patients (60.9%).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\n\u003ch2\u003eComplications\u003c/h2\u003e\n\u003cp\u003ePostoperative complications were evaluated in all 69 patients. Transient lateral gaze incomitance was observed in all patients on postoperative day 1, with median abduction limitation of -2 (-2, -1) PD in the operated eye. This restriction resolved completely by 2 months in all cases. The degree of initial abduction limitation correlated moderately with the amount of CIMRP (\u0026rho;\u0026thinsp;=\u0026thinsp;0.387, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001).\u003c/p\u003e\n\u003cp\u003eFinal overcorrection occurred in 2.90% (2/69) of patients, while undercorrection was observed in 15.94% (11/69), mainly manifesting as residual exodeviation\u0026thinsp;\u0026gt;\u0026thinsp;10 PD or NDD\u0026thinsp;\u0026gt;\u0026thinsp;8 PD. No serious complications such as scleral perforation, muscle slippage, anterior segment ischemia, rotational diplopia, or pattern strabismus occurred during the study period.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eSurgical management of CI-IXT has advanced significantly, with MRs, LRc, and R\u0026amp;R procedures serving as therapeutic mainstays. However, these conventional approaches are limited by high recurrence rates, overcorrection risks, and suboptimal long-term stability, which has continued to drive surgical innovation. The combined LRc and CIMRP technique presented in this study represents a refined and anatomically targeted alternative, particularly suitable for small-angle CI-IXT (\u0026lt;\u0026thinsp;25 PD), by integrating established surgical principles with precision modifications.\u003c/p\u003e\n\u003cdiv id=\"Sec21\" class=\"Section2\"\u003e\n\u003ch2\u003eSurgical Mechanism and Physiological Rationale\u003c/h2\u003e\n\u003cp\u003eThe CIMRP technique embodies a paradigm shift in the surgical approach to CI-IXT. Unlike traditional MR resection, which increases global muscle tension, CIMRP creates a selective mechanical restriction localized to the inferior portion of the MR. This strategy is grounded in the well-established compartmentalized innervation of extraocular muscles, where superior and inferior divisions are separately innervated and may subserve distinct functional roles \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. As the inferior MR is biomechanically pivotal for convergence\u0026mdash;often engaged during downgaze associated with near visual tasks\u0026mdash;targeted intervention in this region allows for more physiological modulation of convergence function.\u003c/p\u003e\n\u003cp\u003eBiomechanically, CIMRP is postulated to generate a force vector with a dominant horizontal (adducting) component. When combined with a calibrated LRc, the net effect preferentially enhances convergence while minimizing disruption to primary gaze alignment. This targeted mechanism likely underlies the significant correction of NDD observed in our cohort, where the median NDD improved from 10 PD preoperatively to 4 PD postoperatively.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec22\" class=\"Section2\"\u003e\n\u003ch2\u003eComparative Efficacy and Technical Advantages\u003c/h2\u003e\n\u003cp\u003eThe defining characteristic of CI-IXT is a clinically significant NDD of \u0026ge;\u0026thinsp;10 PD, making the simultaneous correction of both distance deviation and NDD essential for optimal outcomes. Existing techniques achieve this balance with varying success and limitations:\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eUnilateral LR Recession with MR Resection\u003c/strong\u003e: This approach has demonstrated promising short-term results, with one study reporting 100% success in reducing near deviation and NDD \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. However, efficacy is constrained by small sample sizes and limited follow-up, with long-term success rates dropping substantially (e.g., 42.9% at 26.6 months) \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSlanted Bilateral LR Recession\u003c/strong\u003e (S-BLRc): Leveraging compartmentalized anatomy, S-BLRc has emerged as a preferred technique, showing 80\u0026ndash;90% short-term success and sustained benefits in longer-term studies (57-89.7% success) \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e. However, it requires complex, separate calculations for the superior and inferior LR poles and carries a notable overcorrection risk (reported up to 16.9%) \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eOur Combined LRc\u0026thinsp;+\u0026thinsp;CIMRP Technique\u003c/strong\u003e: In our cohort, this approach achieved an 81.16% success rate at \u0026ge;\u0026thinsp;12 months, with excellent stability (no significant NDD change after 2 months) and a minimal complication profile (2.90% overcorrection, 15.94% undercorrection). These outcomes compare favorably with or exceed those reported for S-BLRc and R\u0026amp;R, particularly in achieving a balanced near-distance correction \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eThe advantages of CIMRP stem from its precise anatomical targeting\u003c/strong\u003e:\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSelective Functional Augmentation\u003c/strong\u003e: The success of CIMRP stems from its alignment with the well-documented non-overlapping zonal innervation of extraocular muscles \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e.It directly tightens the functionally critical inferior MR, the key muscle compartment for convergence.\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eEnhanced Safety\u003c/strong\u003e: Unlike traditional MR resection\u0026mdash;which is associated with transient distance esotropia \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e\u0026mdash;and S-BLRc\u0026mdash;which carries an overcorrection risk of up to 16.9% \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e\u0026mdash;the plication technique preserves the anterior ciliary arteries, markedly reducing the risk of anterior segment ischemia compared to resection, while also achieving a very low overcorrection rate.\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eTheoretical Reversibility and Stability\u003c/strong\u003e: The procedure is theoretically reversible and, by preserving the original MR insertion, may reduce risks of secondary deviation, contributing to postoperative stability.\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cdiv id=\"Sec23\" class=\"Section3\"\u003e\n\u003ch2\u003eDose-Response Relationship and Refined Surgical Planning\u003c/h2\u003e\n\u003cp\u003eThe linear regression model (Corrected NDD\u0026thinsp;=\u0026thinsp;5.973 \u0026times; CIMRP (mm) \u0026ndash; 12.48) establishes a critical, quantifiable dose-response relationship for surgical planning. Each additional millimeter of plication yielded a predictable correction of approximately 6 PD in NDD. While the model's R\u0026sup2; of 0.2042 indicates that plication amount alone explains approximately 20% of outcome variance\u0026mdash;a clinically meaningful contribution for a single parameter given the multifactorial nature of strabismus surgery\u0026mdash;the explanatory power increased to 35.6% (R\u0026sup2; = 0.356) in a multivariate model incorporating preoperative AC/A ratio, age, and preoperative deviation. This finding underscores the importance of patient-specific factors in determining surgical success.\u003c/p\u003e\n\u003cp\u003eNotably, the multivariate model was not used as the primary dosing guide due to its complexity. Instead, we prioritized the simple linear model based solely on CIMRP amount, as it offers the most direct and reproducible guidance for surgeons adopting this novel technique. Future studies with larger, more diverse cohorts may validate a weighted nomogram that integrates AC/A ratio and age, enabling more personalized surgical planning.\u003c/p\u003e\n\u003cp\u003eThe robustness of the dose-response relationship was further confirmed by sensitivity analysis using an alternative NDD indicator, which yielded a similar slope (5.258, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) and supported CIMRP as a consistent predictor of correction efficacy.\u003c/p\u003e\n\u003cp\u003eOur integrated dosing protocol\u0026mdash;1 mm of LR recession per 2 PD of distance deviation, paired with a CIMRP amount calibrated to the preoperative NDD\u0026mdash;provides a physiologically grounded and precise surgical strategy. Based on the regression model, we recommend a minimum CIMRP of 3.5 mm for patients with preoperative NDD\u0026thinsp;\u0026gt;\u0026thinsp;10 PD to achieve optimal convergence enhancement. For the challenging subgroup of small-angle CI-IXT (14\u0026ndash;20 PD), where R\u0026amp;R has historically outperformed unilateral LR recession (58% vs. 34% success) \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e, our technique builds upon this foundation to deliver a higher sustained success rate (81.16%) with lower overcorrection.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec24\" class=\"Section2\"\u003e\n\u003ch2\u003eFunctional Outcomes and Safety Profile\u003c/h2\u003e\n\u003cp\u003eThe significant improvement in control scores (preoperative median: 2 at near, 4 at distance; postoperative: 0 at near, 1 at distance) confirms enhanced fusional stability following surgery. Although the median improvement in stereoacuity was modest (0.1 log units), the fact that 60.9% of patients achieved clinically meaningful improvement is encouraging for functional visual rehabilitation.\u003c/p\u003e\n\u003cp\u003eThe safety profile of CIMRP is favorable. Transient abduction limitation was observed in all patients on postoperative day 1 (median: \u0026minus;2 PD), but resolved completely within 2 months in all cases. The degree of initial limitation correlated moderately with CIMRP amount (\u0026rho;\u0026thinsp;=\u0026thinsp;0.387, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001), suggesting a predictable and self-limited postoperative course. Notably, there were no serious complications such as anterior segment ischemia, scleral perforation, or pattern strabismus.\u003c/p\u003e\n\u003cdiv id=\"Sec25\" class=\"Section3\"\u003e\n\u003ch2\u003eLimitations and Future Directions\u003c/h2\u003e\n\u003cp\u003eThis study represents an exploratory investigation of a novel surgical technique. We acknowledge the inherent limitations of its retrospective, single-center design and explicitly position this work as providing preliminary evidence to inform future prospective randomized controlled trials. The sample size of 69 patients was determined based on feasibility considerations; post hoc power analysis confirmed 80% power (\u0026alpha;\u0026thinsp;=\u0026thinsp;0.05) to detect a moderate effect size (f\u0026thinsp;=\u0026thinsp;0.35) in the primary outcome measures, supporting the adequacy of the cohort for detecting clinically meaningful differences.\u003c/p\u003e\n\u003cp\u003eAdditional limitations include the mean follow-up of 12.4 months, which, while adequate for assessing initial stability, is insufficient to evaluate long-term drift\u0026mdash;a known challenge in strabismus surgery. The absence of a direct control group (e.g., S-BLRc or R\u0026amp;R) precludes definitive comparative conclusions.\u003c/p\u003e\n\u003cp\u003eFuture research should prioritize: (1) prospective, randomized controlled trials directly comparing CIMRP\u0026thinsp;+\u0026thinsp;LRc with established techniques; (2) long-term follow-up studies (3\u0026ndash;5 years) to assess stability; (3) multicenter studies to validate generalizability; and (4) investigations into additional anatomical and biomechanical predictors of surgical outcomes, potentially leading to a weighted nomogram for personalized surgical planning.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn summary, lateral rectus recession combined with compartmentalized inferior medial rectus plication (LRc+CIMRP) offers a safe and effective surgical approach for small angle(\u0026lt;\u0026thinsp;25PD) convergence insufficiency intermittent exotropia (CI-IXT). This technique demonstrates strong near-distance disparity (NDD) correction, stable alignment outcomes, and minimal complications. Based on the established dose-response model, we recommend CIMRP of \u0026ge;\u0026thinsp;3.5 mm for patients with preoperative NDD\u0026thinsp;\u0026gt;\u0026thinsp;10 PD to achieve optimal convergence enhancement. By selectively targeting the pathophysiological mechanism underlying CI-IXT, this approach represents an advance in the surgical armamentarium, though further comparative studies are warranted to precisely define its clinical role.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflicts of interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declared that they have no conflicts of interest to this work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll methods were performed by following per under the relevant guidelines and regulations. Ethics approval for this research was granted by the Medical Ethics Committee of the Tianjin Eye Hospital(KY20224).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was supported by Science and Technology Project of Tianjin Health Commission (TJWJ2025MS036); Nankai University Ophthalmology Institute Open Fund(NKYKK202201), Nankai University Optometry\u0026amp;Vision Science Institute Open Fund ( NKSGY202405)Tianjin Key Medical Discipline (Specialty) Construction Project(NO.TJYXZDXK-016A).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation and data collection were performed by JD,PZ,YPL. All authors recruited and saw patients involved in this study. Data analysis was performed by JD and YPL; all authors interpreted the study data. The first draft of the manuscript was written by JD, with support from YPL, and all authors commented on pre-final versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eKushner BJ, Morton GV. Distance/near differences in intermittent exotropia. Arch Ophthalmol. 1998;116(4):478\u0026ndash;86.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHwang JM. How to better treat patients with intermittent exotropia: a review of surgical treatment of intermittent exotropia. Korean J Ophthalmol. 2022;36(6):550\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePeng M, Poukens V, da Silva Costa RM, Yoo L, Tychsen L, Demer JL. Compartmentalized innervation of primate lateral rectus muscle. Invest Ophthalmol Vis Sci. 2010;51(9):4612\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eda Silva Costa RM, Kung J, Poukens V, Yoo L, Tychsen L, Demer JL. Intramuscular innervation of primate extraocular muscles: unique compartmentalization in horizontal recti. Invest Ophthalmol Vis Sci. 2011;52(5):2830\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMohney BG, Holmes JM. An office-based scale for assessing control in intermittent exotropia. Strabismus. 2006;14(3):147\u0026ndash;50.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLeenheer RS, Wright KW. Mini-plication to treat small-angle strabismus: a minimally invasive procedure. J AAPOS. 2012;16(4):327\u0026ndash;30.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRen M, Wang Q, Wang L. Slanted bilateral lateral rectus recession for convergence insufficiency-type intermittent exotropia: a retrospective study. BMC Ophthalmol. 2020;20(1):287.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKraft SP, Levin AV, Enzenauer RW. Unilateral surgery for exotropia with convergence weakness. J Pediatr Ophthalmol Strabismus. 1995;32(3):183\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChoi MY, Hyung SM, Hwang JM. Unilateral recession-resection in children with exotropia of the convergence insufficiency type. Eye (Lond). 2007;21(3):344\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSnir M, Axer-Siegel R, Bouria D, Sherf I, Yassur Y. Slanted lateral rectus recession for exotropia with convergence weakness. Ophthalmology. 1999;106(5):992\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSuzuki Y, Kono S, Kogure Y, Otsuka M. Slanted and standard lateral rectus recession procedures for convergence insufficiency-type intermittent exotropia in children. Clin Ophthalmol. 2024;18:2453\u0026ndash;60.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi Y, Lin H. Slanted recession on bilateral lateral rectus for intermittent exotropia with convergence insufficiency. BMC Ophthalmol. 2022;22(1):134.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKwon JM, Lee SJ. Long-term results of slanted recession of bilateral lateral rectus muscle for intermittent exotropia with convergence insufficiency. Korean J Ophthalmol. 2019;33(4):353\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSung JY, Yang HK, Hwang JM. Comparison of surgery versus observation for small angle intermittent exotropia. Sci Rep. 2020;10(1):4631.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDemer JL. Compartmentalization of extraocular muscle function. Eye (Lond). 2015;29(2):157\u0026ndash;62.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eClark RA, Demer JL. Differential lateral rectus compartmental contraction during ocular counter-rolling. Invest Ophthalmol Vis Sci. 2014;55(8):4847\u0026ndash;56.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHermann JS. Surgical therapy for convergence insufficiency. J Pediatr Ophthalmol Strabismus. 1981;18(1):28\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003evon Noorden GK. Resection of both medial rectus muscles in organic convergence insufficiency. Am J Ophthalmol. 1976;81(2):223\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMenon V, Singla MA, Saxena R, Phuljhele S. Comparative study of unilateral and bilateral surgery in moderate exotropia. J Pediatr Ophthalmol Strabismus. 2010;47(5):288\u0026ndash;91.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlmahmoudi FH, Al Shamrani M, Khan AM. The use of one muscle recession for horizontal strabismus. Saudi J Ophthalmol. 2018;32(3):200\u0026ndash;3.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"bmc-ophthalmology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"boph","sideBox":"Learn more about [BMC Ophthalmology](http://bmcophthalmol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/boph","title":"BMC Ophthalmology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Intermittent exotropia, Convergence insufficiency, Surgery, Plication","lastPublishedDoi":"10.21203/rs.3.rs-8949721/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8949721/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eThis study aimed to evaluate a novel surgical approach combining lateral rectus recession (LRc) with compartmentalized inferior medial rectus plication (CIMRP) for treating small-angle (\u0026lt;\u0026thinsp;25 prism diopters, PD) convergence insufficiency intermittent exotropia (CI-IXT) in pediatric patients.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA retrospective analysis was conducted on 69 pediatric CI-IXT patients (mean age: 8.13\u0026thinsp;\u0026plusmn;\u0026thinsp;2.46 years) who underwent LRc and CIMRP between September 2022 and January 2024 at Tianjin Eye Hospital. Outcomes including near and distance deviations, near-distance difference (NDD), control scores, stereopsis, and complications were assessed preoperatively and postoperatively at 1 day, 2 months, 6 months, and final follow-up (\u0026ge;\u0026thinsp;12 months).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe mean LRc amount was 7.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.48 mm (range: 6.5\u0026ndash;7.5 mm), and the mean CIMRP amount was 3.56\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39 mm (range: 3.0\u0026ndash;4.0 mm).Significant reductions were observed in near exo-deviation (median: \u0026minus;30 [\u0026minus;\u0026thinsp;32, \u0026minus;\u0026thinsp;28] PD to \u0026minus;\u0026thinsp;12 [\u0026minus;\u0026thinsp;16, \u0026minus;\u0026thinsp;6] PD), distance deviation (\u0026minus;\u0026thinsp;20 [\u0026minus;\u0026thinsp;20, \u0026minus;\u0026thinsp;18] PD to \u0026minus;\u0026thinsp;6 [\u0026minus;\u0026thinsp;10, \u0026minus;\u0026thinsp;1] PD), and NDD (10 [10, 10] PD to 4 [4, 6] PD; all \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Linear regression analysis established a quantitative relationship between the amount of CIMRP and postoperative corrected NDD: Y (Postoperative corrected NDD)\u0026thinsp;=\u0026thinsp;5.973 \u0026times; X (amount of CIMRP in mm)\u0026thinsp;\u0026minus;\u0026thinsp;12.48 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001), indicating that each 1 mm increase in plication amount was associated with an average increase of approximately 5.97 PD in NDD correction. The surgical success rate was 88.41% at both 2 and 6 months, decreasing slightly to 81.16% at the final follow-up. The overcorrection rate peaked at 8.7% at 2 months and subsequently stabilized at 2.9%, whereas the undercorrection rate gradually increased to 15.9%. Control scores and near stereoacuity improved significantly after surgery compared with preoperative values (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001 and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05, respectively).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eLRc combined with CIMRP is an effective and safe approach for small angle CI-IXT(\u0026lt;\u0026thinsp;25PD). We recommend CIMRP of \u0026ge;\u0026thinsp;3.5 mm for preoperative NDD\u0026thinsp;\u0026gt;\u0026thinsp;10 PD based on the established dose-response model. While this targeted technique addresses convergence insufficiency with favorable outcomes, further comparative studies are needed to define its clinical role.\u003c/p\u003e","manuscriptTitle":"Selective Compartmental Plication in Small-Angle Convergence Insufficiency Exotropia: Surgical Outcomes and Predictive Model","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-19 16:24:34","doi":"10.21203/rs.3.rs-8949721/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-29T11:58:48+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-07T09:38:10+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"294454500666345235115335552215333683961","date":"2026-03-29T08:45:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"235230711976099494827436697491061693911","date":"2026-03-29T08:45:04+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-27T14:26:22+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-27T07:08:38+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"39135177009885713019774806362854308300","date":"2026-03-24T14:28:00+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-24T14:17:40+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-23T17:26:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"8070702819344342322004370681294819157","date":"2026-03-20T03:01:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"198299010532032939735199616961076464421","date":"2026-03-19T14:51:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"288330124180448998272096685779105336299","date":"2026-03-19T14:04:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"316528460330749579376643259884641800003","date":"2026-03-19T07:26:50+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-17T07:22:53+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-02-25T05:58:53+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-25T05:08:36+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-25T05:07:55+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Ophthalmology","date":"2026-02-23T17:44:21+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-ophthalmology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"boph","sideBox":"Learn more about [BMC Ophthalmology](http://bmcophthalmol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/boph","title":"BMC Ophthalmology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"59a15fe8-4a0b-4f22-a33d-f241b162fbb4","owner":[],"postedDate":"March 19th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-04-29T12:08:52+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-19 16:24:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8949721","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8949721","identity":"rs-8949721","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}