Vascular Morphology of the Retina and Choroid in Young Adults with Myopia Based on Optical Coherence Tomography Angiography

Vascular Morphology of the Retina and Choroid in Young Adults with Myopia Based on Optical Coherence Tomography Angiography | 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 Vascular Morphology of the Retina and Choroid in Young Adults with Myopia Based on Optical Coherence Tomography Angiography Bing Li, Yimeng Zhang, Kun Yang, Chenxi Li, Xiaomin Zhang, Wei Chen This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7004115/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose This study aims to evaluate changes in retinal and choroidal vascular morphology in young adults with myopia using swept-source optical coherence tomography angiography (SS-OCTA). Methods We conducted comprehensive ophthalmic examinations, obtained SS-OCTA scans (12 × 12 mm 2 ), and documented the clinical characteristics of the participants. Eyes were categorized into low, moderate, and high myopia groups based on spherical equivalent refraction. Average vessel density and morphological parameters were quantitatively analyzed using a semi-automated MATLAB program. Vessel area density was further assessed across nine grids using angiography analysis software. Results The retinal vessel diameter index was significantly lower in the high myopia group than that in the low and moderate myopia groups ( P = 0.021 and P = 0.029, respectively), and showed an inverse correlation with axial length ( P < 0.001). The retinal vessel complexity index was significantly higher in the high myopia group than that in the low myopia group ( P = 0.008), and positively correlated with axial length ( P = 0.001). No significant differences were observed in retinal average vessel density among the three groups ( P = 0.491). In addition, choroidal average vessel density, vessel skeleton density, vessel perimeter index, and vessel complexity index were reduced in the high myopia group ( P = 0.004, P = 0.007, P = 0.022, and P = 0.037 respectively). The vessel diameter index of choroidal Sattler’s and Haller’s layers (CSHL) was notably higher in the high myopia group than that in the low myopia group ( P = 0.021), demonstrating a positive correlation with axial length ( P < 0.001). Conclusions As axial length increases, modifications in retinal vascular morphological parameters, such as diminished retinal vessel diameters and enhanced retinal branching, are observed to precede alterations in the average retinal vessel density. Additionally, in cases of high myopia, significant changes are evident in both choroidal vessel density and vascular morphology. axial length vessel density vessel diameter index vascular morphology myopia OCTA Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Key points 1 Myopia induces changes in retinal morphological parameters, including reduced vessel diameters and increased branching, which precede alterations in the average retinal vessel density. 2. Myopia is associated with a reduction in choroidal vessel density, vessel skeleton density, vessel perimeter index, and vessel complexity index, alongside an increase in vascular diameters. 3. Morphological parameters of retina and choroid may offer an additional method for assessing the progression of myopia, and even provide new insights into the pathogenesis of myopia. Introduction Myopia is a common ophthalmic condition that has raised public concern due to its increasing prevalence. Complications associated with myopia, including retinal detachment, choroidal neovascularization, glaucoma, and cataracts, significantly impact patients’ vision and quality of life. The development and progression of myopia are influenced by genetic and environmental factors, leading to an excessive increase in axial length of eye [ 1 ]. Current research indicates that retinal dopamine metabolism disorders, choroidal thinning, and scleral hypoxia contribute to the development of myopia [ 2 – 4 ]. However, the specific mechanisms remain unclear, and existing research on myopia lacks comprehensive insights into the vascular morphology of the retina and choroid. Therefore, a detailed understanding of the vascular morphological changes in the retina and choroid is crucial for exploring the pathogenesis of myopia. With the rapid technological advancements in optical coherence tomography (OCT) devices, particularly the use of swept-source OCT (SS-OCT) in clinical applications, OCT-angiography (OCTA) has provided substantial evidence of vascular changes in individuals with myopia. Studies have shown that choroidal thinning and a reduction in vessel density within the choroidal Sattler’s and Haller’s layers (CSHL) occur as axial length increases in myopic eyes [ 5 ]. Additionally, pathological myopia is associated with lower choroidal vessel volume and reduced values of luminal and stromal areas in the choroid [ 6 , 7 ]. In addition to measure vascular density, additional parameters describing microvascular morphology, such as vessel diameter, vessel skeleton density, vessel perimeter index, and vessel complexity index, may be valuable in evaluating vascular alterations in ocular diseases. A decline in retinal vascular density and an increase in average vascular diameter have been linked to the progression of diabetic retinopathy [ 8 ]. Moreover, the value of choroidal vessel diameter and choroidal thickness in the form-deprivation myopia group were smaller than those in the normal control group[ 9 ]. In this study, we used a semi-automated algorithm with an SS-OCTA device to quantify the vascular morphological parameters of the retina and choroid in individuals with myopia. We demonstrated that these parameters are associated with disease severity and provide additional insights into the variations in microvascular morphology in myopia. Methods Investigation and grouping This cross-sectional observational cohort study was conducted at Tianjin Eye Hospital. Ethical approval was obtained from the Medical Ethics Committee of Tianjin Eye Hospital (YK-2023071). Patients with myopia who visited Tianjin Eye Hospital were recruited. The inclusion criteria were as follows: (1) age 18–40 years and (2) signed informed consent and volunteered to participate in this study. The exclusion criteria were as follows: (1) ocular disease affecting vision (including keratitis, glaucoma, and retinal artery/vein occlusion), (2) history of ocular surgery, (3) history of contact lens wear during the past month, and (4) more than 2.00 D of astigmatism. A total of 101 eyes from 52 subjects with myopia met the study criteria. Spherical equivalents (SE) were obtained based on refraction, and eyes were categorized into three groups: low myopia group (LM, − 3.00D < SE ≤ − 0.50D), moderate myopia group (MM, − 6.00 D < SE ≤ − 3.00 D), and high myopia group (HM, SE ≤ − 6.00 D). Ophthalmic examinations and image processing Trained ophthalmologists and optometrists conducted comprehensive clinical history, and ophthalmic examinations, including assessment of best-corrected visual acuity, refraction, intraocular pressure, axial length, corneal topography, and swept-source OCT (Bmizar; TowardPi Medical Technology, Beijing, China). The swept-source OCT device operated at a scan speed of 400,000 A-scans per second. A 12 × 12 mm 2 OCT rectangular scan pattern was employed to acquire high-quality images for subsequent analysis. Automated quality assessment was performed for each OCT scan, with scores exceeding eight considered suitable for analysis. Morphological parameters included vessel diameter index, vessel skeleton density, vessel perimeter index, and vessel complexity index. Average vascular density and morphological parameters were quantitatively analyzed using a semi-automated MATLAB program. An independent researcher with expertise in OCT data analysis performed all data analyses [ 9 ]. OCTA images were transformed into binary format, and a multiscale Hessian filter was applied to evaluate vascular parameters (Fig. 1 ). Vessel diameter was calculated by measuring the distance between these intersections at each vessel junction. Other morphological parameters were calculated based on this binarized version. En face images were segmented into the following nine partitions: supratemporal (ST), superior (S), supranasal (SN), temporal (T), central macular area (C), nasal (N), inferotemporal (IT), inferior (I), and inferonasal (IN) regions (Fig. S1 ). The angiography analysis software was used to analyze vessel area density, choroidal thickness, and vessel volume across each section. Statistical analysis Data were analyzed using SPSS (IBM, Armonk, NY, USA) and Prism (GraphPad Software, San Diego, CA, USA). Normality and homogeneity of variance were assessed for the dataset. Parametric (one-way ANOVA) or nonparametric tests were applied based on data distribution. Spearman’s rank correlation coefficient was used to evaluate correlations, with statistical significance set at p = 0.05. Results 1. General and Clinical Characteristics of Participants In this cross-sectional study, 101 eyes from 52 participants were included. The cohort comprised 13 eyes from 7 participants in the low myopia group (LM), 55 eyes from 28 participants with moderate myopia (MM), and 33 eyes from 17 participants with high myopia (HM). Table 1 presents the general and clinical characteristics of the participants. Table 1 General and Clinical Characteristics of Participants in this study Subjects LM MM HM P Patients /eyes, n 7/13 28 /55 17/33 NA Age (y) 24(21, 29) 23(20,26) 26 (21, 31) NA Gender (M/F), n 2/5 11/17 5/12 NA IOP (mm Hg) 15.65 ± 1.75 16.02 ± 2.61 15.78 ± 2.20 NA SE (D) –2.38(–0.86, − 2.82) –4.75(–3.88, − 5.47) –6.88(–6.44, − 9.00) 0.001 AL (mm) 22.54(22.00, 23.78) 25.42(24.77, 25.89) 26.24(25.75, 28.17) < 0.001 Data of IOP are presented as mean ± SD; Data of SE and AL are presented as median (first and third quartiles). M denotes male; F denotes female; LM, low myopia group; MM, moderate myopia group; HM, high myopia group; IOP, intraocular pressure; SE, spherical equivalent; AL, axial length. 2. Retinal vessel density and morphology in Young Adults with Myopia Participants were divided into three groups based on spherical equivalent refraction, and retinal changes in myopic eyes were assessed. No significant difference was observed in retinal average vessel density among the groups ( P = 0.491; Fig. 2 A-B). Interestingly, the vessel diameter index was significantly lower in the high myopia group compared to the low and moderate myopia groups ( P = 0.021 and P = 0.029, respectively; Fig. 2 C), and vessel diameter index showed an inverse correlation with axial length ( P < 0.001, Fig. 2 D). Retinal vessel density images were segmented into nine regions to analyze the superficial vascular complex (SVC) and the deep vascular complex (DVC) separately. No significant difference in vessel area density was observed neither in SVC or DVC across all sections (Fig. 2 E, 2 F) The retinal vessel skeleton density and vessel perimeter index were positively correlated with axial length ( P < 0.001 and P = 0.003, respectively, Fig. 3 B, 3 D), but no significant difference among the three groups (Fig. 3 A, 3 C). The retinal vessel complexity index was significantly higher in the high myopia group than that in the low myopia group ( P = 0.008), and positively correlated with axial length ( P = 0.001). 3. Changes of the Choroidal vessel density and morphology in Young Adults with Myopia Changes in choroidal vessels were evaluated in myopia eyes. The choroidal average vessel density was notably reduced in the high myopia group compared to the other two groups ( P = 0.048 and P = 0.005, respectively; Fig. 4 A), with a decrease in vessel density observed as axial length increased ( P = 0.030; Fig. 4 B). The vessel diameter index of the Choroidal Sattler’s and Haller’s (CSHL) was elevated in the high myopia group relative to the low myopia group ( P = 0.021; Fig. 4 C), exhibiting a positive correlation with axial length ( P < 0.001; Fig. 4 D). Additionally, vessel area density in the choroidal capillary plexus (CCP) and CSHL were assessed across nine sections. No significant differences in the CCP vessel density were found among the groups (Fig. 4 E). However, the CSHL vessel density demonstrated a declining trend in the high myopia group, with significant differences observed in most sections, except for the temporal, superior, and temporal regions (Fig. 4 F). In the high myopia group, the choroidal vessel skeleton density, vessel perimeter index, and vessel complexity index were significantly reduced ( P = 0.007, P = 0.022, and P = 0.037 respectively; Fig. 5 A, 5 C, 5 E) and demonstrated a negative correlation with axial length ( P < 0.001, P = 0.002, and P = 0.001 respectively; Fig. 5 B, 5 D, 5 F). Furthermore, choroidal thickness and vessel volume were assessed across nine sections. A significant reduction in choroidal thickness was observed in the high myopia group across most sections, except for the nasal-inferior region (Fig. S1 A). Choroidal volume showed similar results (Fig. S1 B). Discussion In this study, we initially assessed the changes in retinal vascular density and morphology in young adults with myopia. As axial elongation of the eye occurred, alterations in retinal morphological parameters, such as reduced vessel diameters and increased branching, were observed to precede changes in retinal vessel density. We hypothesized that the fundamental requirement for blood supply in young myopic individuals without myopic maculopathy is likely maintained, suggesting the potential for retinal vessel remodeling in these individuals. Therefore, changes in retinal vascular morphology may precede alterations in vascular density. Therefore, the morphological parameters of retinal vessels may serve as potential early biomarkers for monitoring the progression of myopia. Previous studies have assessed retinal blood flow using various techniques, such as color doppler ultrasonography technique [ 10 ], retinal oximetry [ 11 ], color fundus images [ 12 ], and optical coherence angiography [ 8 , 13 ], with mixed results. Some studies have suggested a decrease in retinal blood flow in high myopia [ 14 ] [ 15 ], while others showed that retinal vessel density decreased only in the central macular region with increasing myopic diopters, with no change was detected in other regions[ 13 ]. Additionally, some studies reported that retinal arteriolar and venous oxygen saturation decreased with myopia progression [ 11 ]. Our study found no significant change in retinal vessel density with an increased axis length, which is inconsistent with other studies. Discrepancies in detection techniques, zoning patterns, scanning area of SS-OCT, and variations in axial length distributions might have contributed to these conflicting conclusions. Moreover, our study subjects were young individuals with myopia but without myopic maculopathy, suggesting that the stable retinal blood supply might be partly explained by the retinal blood flow regulatory mechanism within a compensatory range [ 16 ]. Examining microvascular changes through vessel diameter assessment could enhance our understanding of ocular disease pathophysiology[ 17 , 18 ]. Previous studies have shown a correlation between the tapering of retinal vessel diameter and elongated axial length, consistent with our findings[ 19 – 21 ]. A cross-sectional study reported increased wall thickness and the wall-to-lumen ratio increased in myopic eyes, but no significant change in central retinal artery diameter [ 10 ], supporting the possibility of retinal vessel remodeling in the myopic eyes. OCTA provided vascular morphologic information based on blood cell movement, potentially offering a more accurate assessment of vascular caliber. Additionally, we also evaluated choroidal vascular density and morphology in individuals with myopia. Consistent with prior studies, our findings indicated a reduction in both choroidal vessel density and choroidal thickness as axial length increases [ 5 – 7 , 13 , 22 ]. Comparable outcomes have been observed in animal models, including mice [ 23 ], guinea pigs [ 24 , 25 ], and marmosets [ 26 ]. It has been suggested that enhanced choroidal blood perfusion may decelerate the progression of myopia [ 27 , 28 ], whereas diminished choroidal blood perfusion could potentially induce myopia in guinea pigs [ 29 ]. In our investigation, the diameter of the vessels in the choroidal Sattler’s and Haller’s layers (CSHL) was found to be significantly greater in the high myopia group compared to the low myopia group, and this increase was positively correlated with axial length. The underlying mechanisms responsible for vascular dilation in the myopic choroid remain unclear and may involve complex regulatory processes, including neural control and the regulation of vasoactive molecules [ 16 , 30 , 31 ]. This study is subject to several limitations. Firstly, the participants were predominantly young individuals undergoing evaluation for corneal refractive surgery, and the relatively small sample size may have introduced potential bias. Secondly, as a cross-sectional study, this research does not establish a causal relationship between myopia and vascular changes in the retina and choroid. To investigate this causal relationship, further prospective studies with larger sample sizes are necessary. Conclusions The progression of myopia leads to reduced retinal vessel diameters and increased retinal branching. Myopia is associated with a reduction in choroidal vessel density, vessel skeleton density, vessel perimeter index, and vessel complexity index, alongside an increase in vascular diameters. Morphological parameters of retina and choroid may offer an additional method for assessing the progression of myopia, and even provide new insights into the pathogenesis of myopia. Abbreviations SS-OCTA Swept-source optical coherence tomography angiography CSHL Choroidal Sattler’s and Haller’s layers SE Spherical equivalents ST Supratemporal S Superior SN Supranasal T Temporal C Central macular area N Nasal IT Inferotemporal I Inferior IN Inferonasal LM Low myopia group MM Moderate myopia HM High myopia IOP Intraocular pressure AL Axial length M Male F Female VDI Vessel diameter index SVC Superficial vascular complex DVC Deep vascular complex CCP Choroidal capillary plexus Declarations Ethics approval and consent to participate This study was conducted at Tianjin Eye Hospital. Ethical approval was obtained from the Medical Ethics Committee of Tianjin Eye Hospital (YK-2023071). This study adhered to the Declaration of Helsinki. Informed consent was obtained from participants prior to the study. Consent for publication Not applicable. Availability of data and materials No datasets were generated or analysed during the current study. The data supporting this study's findings are available from the corresponding authors. Competing interests The authors declare that they have no competing interests. Funding This work was supported by the National Natural Science Foundation of China (82160205); grant 2021D01F46 from the Xinjiang Autonomous Region Science Foundation of China, grant YKZD2003 from the Tianjin Eye Hospital; and Tianjin Key Medical Discipline (Specialty) Construction Project (No. TJYXZDXK-016A, No. TJYXZDXK-037A). Authors’ contributions W.C. and X.Z. contributed to the direction and guidance of this work. Research Design: W.C. and B.L. Statistical analysis: B.L., Y.Z., K.Y., and C.L. Drafting of the manuscript: B.L. and Y.Z. Revision of the manuscript: W.C. and X.Z. All authors read and approved the final manuscript. Acknowledgements Xiaomin, Zhang and Wei Chen are co-corresponding authors . The authors appreciate Editage (www.editage.cn) for the English language editing. ORCID IDs Bing Li https://orcid.org/0000-0003-3505-4909 Yimeng Zhang https://orcid.org/0009-0007-0171-1006 Xiaomin Zhang https://orcid.org/0000-0003-4898-4152 Wei Chen https://orcid.org/0000-0003-3505-4909 References Baird PN, Saw SM, Lanca C, Guggenheim JA, Smith Iii EL, Zhou X, Matsui KO, Wu PC, Sankaridurg P, Chia A et al : Myopia . Nat Rev Dis Primers 2020, 6 (1):99. Wu H, Chen W, Zhao F, Zhou Q, Reinach PS, Deng L, Ma L, Luo S, Srinivasalu N, Pan M et al : Scleral hypoxia is a target for myopia control . Proc Natl Acad Sci U S A 2018, 115 (30):E7091-E7100. 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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-7004115","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":497538113,"identity":"e19ed6a6-5ecb-4dac-bacc-bf258781050e","order_by":0,"name":"Bing Li","email":"","orcid":"","institution":"Tianjin Medical University Eye Hospital","correspondingAuthor":false,"prefix":"","firstName":"Bing","middleName":"","lastName":"Li","suffix":""},{"id":497538114,"identity":"bf0b0689-f37c-458a-915e-bf709156ef43","order_by":1,"name":"Yimeng Zhang","email":"","orcid":"","institution":"Tianjin Eye Hospital, Nankai University Affiliated Eye Hospital, Tianjin Medical University, Tianjin Eye Institute","correspondingAuthor":false,"prefix":"","firstName":"Yimeng","middleName":"","lastName":"Zhang","suffix":""},{"id":497538115,"identity":"ce79ecc4-fc2f-497c-95a5-f95b816e116d","order_by":2,"name":"Kun Yang","email":"","orcid":"","institution":"Tianjin Eye Hospital, Nankai University Affiliated Eye Hospital, Tianjin Medical University, Tianjin Eye Institute","correspondingAuthor":false,"prefix":"","firstName":"Kun","middleName":"","lastName":"Yang","suffix":""},{"id":497538116,"identity":"8591ab07-42b7-4b55-a972-968f0d663727","order_by":3,"name":"Chenxi Li","email":"","orcid":"","institution":"Tianjin University","correspondingAuthor":false,"prefix":"","firstName":"Chenxi","middleName":"","lastName":"Li","suffix":""},{"id":497538117,"identity":"adc0cee0-83dd-42bd-9986-b968d3c75602","order_by":4,"name":"Xiaomin Zhang","email":"","orcid":"","institution":"Tianjin Medical University Eye Hospital","correspondingAuthor":false,"prefix":"","firstName":"Xiaomin","middleName":"","lastName":"Zhang","suffix":""},{"id":497538118,"identity":"3c00f201-6ece-4bb2-9854-64b1179ec849","order_by":5,"name":"Wei Chen","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8UlEQVRIiWNgGAWjYDACCQjJw8/efPDBhwoJOXlitchI9hxLNpxxxsLYsIE4LQw2BjdyzKR52yoSGQ4Q0ME/u/nYY54KCx6DMweMDXjnSSQwNjA/fHQDnyV3jqUb85yR4JE83pD4QHKbRB47A5uxcQ4eLQYSQPfktknw8J05cNjAcJtEMWMDD5s0fi3536Rz/0nwMNxIbJNInCOR2HCAoJYcNuncBgkegRvJbBIHG4jQInEjzUz6zzGgX3qOMRs2HJMwNmwm4Bf+GcnPJGfU1Nnzs/d/fPynpk5Onr354WN8WrAAZtKUj4JRMApGwSjAAgDAE0mIpxX9yQAAAABJRU5ErkJggg==","orcid":"","institution":"Tianjin Eye Hospital, Nankai University Affiliated Eye Hospital, Tianjin Medical University, Tianjin Eye Institute","correspondingAuthor":true,"prefix":"","firstName":"Wei","middleName":"","lastName":"Chen","suffix":""}],"badges":[],"createdAt":"2025-06-29 17:23:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7004115/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7004115/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":88780810,"identity":"83c970cb-654c-4338-9b1e-580379e9a23f","added_by":"auto","created_at":"2025-08-11 10:49:03","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1144202,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative optical coherence tomography angiography (OCTA) images with dimensions of 12 × 12 mm². (A) The original en-face OCTA image of the retina. (B) A binarized blood flow image of the retina, processed using a semi-automated MATLAB program. (C) A vessel density map illustrating binary vessels within the retina. (D) A vessel diameter map displaying binary vessels in the retina. (E) The original en-face OCTA image of the choroid. (F) A binarized blood flow image of the choroid, processed via a semi-automated MATLAB program. (G) A vessel density map illustrating binary vessels within the choroid. (H) A vessel diameter map displaying binary vessels in the choroid.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7004115/v1/42c6322aa16a250f80bda01e.png"},{"id":88782000,"identity":"08c4bcc5-ac18-4de5-a3e7-0a9c706fe99f","added_by":"auto","created_at":"2025-08-11 10:57:03","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1293385,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysis of retinal vessel density and vessel diameter index among the low myopia (LM), moderate myopia (MM), and high myopia (HM) groups. (A) Comparison of the average vessel density of the retina among the three groups. (B) A scatter plot illustrating the relationship between axial length (x-axis) and retinal average vessel density (y-axis). (C) Comparison of the vessel diameter index of the retina across the three groups. (D) A scatter plot depicting the correlation between axial length (x-axis) and retinal vessel diameter index (y-axis). (E-F) A comparative analysis of vessel density in the retinal superficial vascular complex (E) and deep vascular complex (F) across the nine grids: Supratemporal (ST), superior (S), supranasal (SN), temporal (T), central macular (C), nasal (N), inferotemporal (IT), inferior (I), inferonasal (IN). (* \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05, ** \u003cem\u003ep \u003c/em\u003e\u0026lt; 0.01)\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7004115/v1/4b1dec2e261208fa88e4f20f.png"},{"id":88780814,"identity":"64d1d3ef-e8d8-4d2f-8848-e0fd5c469e8d","added_by":"auto","created_at":"2025-08-11 10:49:03","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":914309,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysis of retinal other morphometric parameters among the low myopia (LM), moderate myopia (MM), and high myopia (HM) groups. (A) Comparison of retinal vessel skeleton density among the three groups. (B) A scatter plot illustrating the relationship between axial length (x-axis) and retinal vessel skeleton density (y-axis). (C) Comparison of retinal vessel perimeter index among the three groups. (D) A scatter plot depicting the correlation between axial length (x-axis) and retinal vessel perimeter index (y-axis). (E) Comparison of retinal vessel complexity index among the three groups. (F) A scatter plot depicting the correlation between axial length (x-axis) and retinal vessel complexity index (y-axis). (* \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05, ** \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01)\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7004115/v1/2c822ceab4df5b09e662ad67.png"},{"id":88782001,"identity":"5bd8cac1-d982-44aa-8a01-43670ca2d7d8","added_by":"auto","created_at":"2025-08-11 10:57:03","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1318818,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysis of choroidal vessel density and vessel diameter index among the low myopia (LM), moderate myopia (MM), and high myopia (HM) groups. (A) Comparison of the average vessel density of choroid among the three groups. (B) A scatter plot illustrating the relationship between axial length (x-axis) and choroidal average vessel density (y-axis) (C) Comparison of choroidal vessel diameter index among the three groups. (D) A scatter plot depicting the correlation between axial length (x-axis) and choroidal vessel diameter index (y-axis) (E) Comparison of vessel area density in the choriocapillary complex across the nine grids. (F) Comparison of vessel area density in the choroidal Sattler’s and Haller’s layers across the nine grids. Supratemporal (ST), superior (S), supranasal (SN), temporal (T), central macular (C), nasal (N), inferotemporal (IT), inferior (I), and inferonasal (IN) are represented. (* \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05, ** \u003cem\u003ep\u003c/em\u003e\u0026lt; 0.01)\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7004115/v1/aaf8275ddd7fc27a1da5acfb.png"},{"id":88782506,"identity":"53807863-39c8-4c82-a780-3bee0a96a431","added_by":"auto","created_at":"2025-08-11 11:05:03","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":974054,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysis of choroidal other morphometric parameters index among the low myopia (LM), moderate myopia (MM), and high myopia (HM) groups. (A) Comparison of the vessel skeleton density of the choroid in the three groups. (B) A scatter plot illustrating the relationship between axial length (x-axis) and choroidal vessel skeleton density (y-axis). (C) Comparison of the vessel perimeter index of the choroid in the three groups. (D) A scatter plot depicting the correlation between axial length (x-axis) and choroidal vessel perimeter index (y-axis). (E) Comparison of the vessel complexity density of choroid in the three groups. (F) A scatter plot depicting the correlation between axial length (x-axis) and choroidal vessel complexity index (y-axis). (* p \u0026lt; 0.05, ** p \u0026lt; 0.01)\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7004115/v1/e43c279c15b656f7a57b9d02.png"},{"id":92386325,"identity":"38a8a094-8fca-4953-ab20-6ba098aea020","added_by":"auto","created_at":"2025-09-29 07:31:55","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7501391,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7004115/v1/bf784766-fe3b-4c5a-8b9d-9dd9f7ca4063.pdf"},{"id":88780817,"identity":"1118ec1b-0680-4451-9eb5-6425ef680d46","added_by":"auto","created_at":"2025-08-11 10:49:03","extension":"doc","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":706524,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryResults.doc","url":"https://assets-eu.researchsquare.com/files/rs-7004115/v1/619160ee1cdc051d60f87ee5.doc"}],"financialInterests":"No competing interests reported.","formattedTitle":"Vascular Morphology of the Retina and Choroid in Young Adults with Myopia Based on Optical Coherence Tomography Angiography","fulltext":[{"header":"Key points","content":"\u003cp\u003e1 Myopia induces changes in retinal morphological parameters, including reduced vessel diameters and increased branching, which precede alterations in the average retinal vessel density.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e2. Myopia is associated with a reduction in choroidal vessel density, vessel skeleton density, vessel perimeter index, and vessel complexity index, alongside an increase in vascular diameters.\u003c/p\u003e\n\u003cp\u003e3. Morphological parameters of retina and choroid may offer an additional method for assessing the progression of myopia, and even provide new insights into the pathogenesis of myopia.\u003c/p\u003e"},{"header":"Introduction","content":"\u003cp\u003eMyopia is a common ophthalmic condition that has raised public concern due to its increasing prevalence. Complications associated with myopia, including retinal detachment, choroidal neovascularization, glaucoma, and cataracts, significantly impact patients’ vision and quality of life. The development and progression of myopia are influenced by genetic and environmental factors, leading to an excessive increase in axial length of eye [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Current research indicates that retinal dopamine metabolism disorders, choroidal thinning, and scleral hypoxia contribute to the development of myopia [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e–\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. However, the specific mechanisms remain unclear, and existing research on myopia lacks comprehensive insights into the vascular morphology of the retina and choroid. Therefore, a detailed understanding of the vascular morphological changes in the retina and choroid is crucial for exploring the pathogenesis of myopia.\u003c/p\u003e\u003cp\u003e With the rapid technological advancements in optical coherence tomography (OCT) devices, particularly the use of swept-source OCT (SS-OCT) in clinical applications, OCT-angiography (OCTA) has provided substantial evidence of vascular changes in individuals with myopia. Studies have shown that choroidal thinning and a reduction in vessel density within the choroidal Sattler’s and Haller’s layers (CSHL) occur as axial length increases in myopic eyes [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Additionally, pathological myopia is associated with lower choroidal vessel volume and reduced values of luminal and stromal areas in the choroid [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn addition to measure vascular density, additional parameters describing microvascular morphology, such as vessel diameter, vessel skeleton density, vessel perimeter index, and vessel complexity index, may be valuable in evaluating vascular alterations in ocular diseases. A decline in retinal vascular density and an increase in average vascular diameter have been linked to the progression of diabetic retinopathy [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Moreover, the value of choroidal vessel diameter and choroidal thickness in the form-deprivation myopia group were smaller than those in the normal control group[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In this study, we used a semi-automated algorithm with an SS-OCTA device to quantify the vascular morphological parameters of the retina and choroid in individuals with myopia. We demonstrated that these parameters are associated with disease severity and provide additional insights into the variations in microvascular morphology in myopia.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cb\u003eInvestigation and grouping\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis cross-sectional observational cohort study was conducted at Tianjin Eye Hospital. Ethical approval was obtained from the Medical Ethics Committee of Tianjin Eye Hospital (YK-2023071).\u003c/p\u003e\u003cp\u003ePatients with myopia who visited Tianjin Eye Hospital were recruited. The inclusion criteria were as follows: (1) age 18–40 years and (2) signed informed consent and volunteered to participate in this study. The exclusion criteria were as follows: (1) ocular disease affecting vision (including keratitis, glaucoma, and retinal artery/vein occlusion), (2) history of ocular surgery, (3) history of contact lens wear during the past month, and (4) more than 2.00 D of astigmatism. A total of 101 eyes from 52 subjects with myopia met the study criteria.\u003c/p\u003e\u003cp\u003eSpherical equivalents (SE) were obtained based on refraction, and eyes were categorized into three groups: low myopia group (LM, − 3.00D \u0026lt; SE ≤ − 0.50D), moderate myopia group (MM, − 6.00 D \u0026lt; SE ≤ − 3.00 D), and high myopia group (HM, SE ≤ − 6.00 D).\u003c/p\u003e\u003cp\u003e\u003cb\u003eOphthalmic examinations and image processing\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTrained ophthalmologists and optometrists conducted comprehensive clinical history, and ophthalmic examinations, including assessment of best-corrected visual acuity, refraction, intraocular pressure, axial length, corneal topography, and swept-source OCT (Bmizar; TowardPi Medical Technology, Beijing, China).\u003c/p\u003e\u003cp\u003eThe swept-source OCT device operated at a scan speed of 400,000 A-scans per second. A 12 × 12 mm\u003csup\u003e2\u003c/sup\u003e OCT rectangular scan pattern was employed to acquire high-quality images for subsequent analysis. Automated quality assessment was performed for each OCT scan, with scores exceeding eight considered suitable for analysis. Morphological parameters included vessel diameter index, vessel skeleton density, vessel perimeter index, and vessel complexity index. Average vascular density and morphological parameters were quantitatively analyzed using a semi-automated MATLAB program. An independent researcher with expertise in OCT data analysis performed all data analyses [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. OCTA images were transformed into binary format, and a multiscale Hessian filter was applied to evaluate vascular parameters (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Vessel diameter was calculated by measuring the distance between these intersections at each vessel junction. Other morphological parameters were calculated based on this binarized version.\u003c/p\u003e\u003cp\u003eEn face images were segmented into the following nine partitions: supratemporal (ST), superior (S), supranasal (SN), temporal (T), central macular area (C), nasal (N), inferotemporal (IT), inferior (I), and inferonasal (IN) regions (Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e). The angiography analysis software was used to analyze vessel area density, choroidal thickness, and vessel volume across each section.\u003c/p\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eData were analyzed using SPSS (IBM, Armonk, NY, USA) and Prism (GraphPad Software, San Diego, CA, USA). Normality and homogeneity of variance were assessed for the dataset. Parametric (one-way ANOVA) or nonparametric tests were applied based on data distribution. Spearman’s rank correlation coefficient was used to evaluate correlations, with statistical significance set at \u003cem\u003ep\u003c/em\u003e = 0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cb\u003e1. General and Clinical Characteristics of Participants\u003c/b\u003e\u003c/p\u003e\u003cp\u003eIn this cross-sectional study, 101 eyes from 52 participants were included. The cohort comprised 13 eyes from 7 participants in the low myopia group (LM), 55 eyes from 28 participants with moderate myopia (MM), and 33 eyes from 17 participants with high myopia (HM). Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e presents the general and clinical characteristics of the participants.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eGeneral and Clinical Characteristics of Participants in this study\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSubjects\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLM\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMM\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHM\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePatients /eyes, n\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7/13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28 /55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e17/33\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNA\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge (y)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e24(21, 29)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e23(20,26)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e26 (21, 31)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNA\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGender (M/F), n\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2/5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11/17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5/12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNA\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIOP (mm Hg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e15.65\u0026thinsp;\u0026plusmn;\u0026thinsp;1.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16.02\u0026thinsp;\u0026plusmn;\u0026thinsp;2.61\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e15.78\u0026thinsp;\u0026plusmn;\u0026thinsp;2.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNA\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSE (D)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026ndash;2.38(\u0026ndash;0.86, \u0026minus;\u0026thinsp;2.82)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u0026ndash;4.75(\u0026ndash;3.88, \u0026minus;\u0026thinsp;5.47)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026ndash;6.88(\u0026ndash;6.44, \u0026minus;\u0026thinsp;9.00)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAL (mm)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e22.54(22.00, 23.78)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e25.42(24.77, 25.89)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e26.24(25.75, 28.17)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eData of IOP are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD; Data of SE and AL are presented as median (first and third quartiles). M denotes male; F denotes female; LM, low myopia group; MM, moderate myopia group; HM, high myopia group; IOP, intraocular pressure; SE, spherical equivalent; AL, axial length.\u003c/p\u003e\u003cp\u003e\u003cb\u003e2. Retinal vessel density and morphology in Young Adults with Myopia\u003c/b\u003e\u003c/p\u003e\u003cp\u003eParticipants were divided into three groups based on spherical equivalent refraction, and retinal changes in myopic eyes were assessed. No significant difference was observed in retinal average vessel density among the groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.491; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA-B). Interestingly, the vessel diameter index was significantly lower in the high myopia group compared to the low and moderate myopia groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.021 and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.029, respectively; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC), and vessel diameter index showed an inverse correlation with axial length (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eD). Retinal vessel density images were segmented into nine regions to analyze the superficial vascular complex (SVC) and the deep vascular complex (DVC) separately. No significant difference in vessel area density was observed neither in SVC or DVC across all sections (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eE, \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eF)\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe retinal vessel skeleton density and vessel perimeter index were positively correlated with axial length (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001 and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.003, respectively, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB, \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eD), but no significant difference among the three groups (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA, \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eC). The retinal vessel complexity index was significantly higher in the high myopia group than that in the low myopia group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.008), and positively correlated with axial length (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e3. Changes of the Choroidal vessel density and morphology in Young Adults with Myopia\u003c/b\u003e\u003c/p\u003e\u003cp\u003eChanges in choroidal vessels were evaluated in myopia eyes. The choroidal average vessel density was notably reduced in the high myopia group compared to the other two groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.048 and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.005, respectively; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA), with a decrease in vessel density observed as axial length increased (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.030; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eB). The vessel diameter index of the Choroidal Sattler\u0026rsquo;s and Haller\u0026rsquo;s (CSHL) was elevated in the high myopia group relative to the low myopia group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.021; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eC), exhibiting a positive correlation with axial length (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eD). Additionally, vessel area density in the choroidal capillary plexus (CCP) and CSHL were assessed across nine sections. No significant differences in the CCP vessel density were found among the groups (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eE). However, the CSHL vessel density demonstrated a declining trend in the high myopia group, with significant differences observed in most sections, except for the temporal, superior, and temporal regions (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eF).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIn the high myopia group, the choroidal vessel skeleton density, vessel perimeter index, and vessel complexity index were significantly reduced (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.007, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.022, and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.037 respectively; Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eA, \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eC, \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eE) and demonstrated a negative correlation with axial length (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.002, and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001 respectively; Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eB, \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eD, \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eF).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFurthermore, choroidal thickness and vessel volume were assessed across nine sections. A significant reduction in choroidal thickness was observed in the high myopia group across most sections, except for the nasal-inferior region (Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003eA). Choroidal volume showed similar results (Fig. \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003eB).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, we initially assessed the changes in retinal vascular density and morphology in young adults with myopia. As axial elongation of the eye occurred, alterations in retinal morphological parameters, such as reduced vessel diameters and increased branching, were observed to precede changes in retinal vessel density. We hypothesized that the fundamental requirement for blood supply in young myopic individuals without myopic maculopathy is likely maintained, suggesting the potential for retinal vessel remodeling in these individuals. Therefore, changes in retinal vascular morphology may precede alterations in vascular density. Therefore, the morphological parameters of retinal vessels may serve as potential early biomarkers for monitoring the progression of myopia.\u003c/p\u003e\u003cp\u003ePrevious studies have assessed retinal blood flow using various techniques, such as color doppler ultrasonography technique [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], retinal oximetry [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], color fundus images [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], and optical coherence angiography [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], with mixed results. Some studies have suggested a decrease in retinal blood flow in high myopia [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], while others showed that retinal vessel density decreased only in the central macular region with increasing myopic diopters, with no change was detected in other regions[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Additionally, some studies reported that retinal arteriolar and venous oxygen saturation decreased with myopia progression [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Our study found no significant change in retinal vessel density with an increased axis length, which is inconsistent with other studies. Discrepancies in detection techniques, zoning patterns, scanning area of SS-OCT, and variations in axial length distributions might have contributed to these conflicting conclusions. Moreover, our study subjects were young individuals with myopia but without myopic maculopathy, suggesting that the stable retinal blood supply might be partly explained by the retinal blood flow regulatory mechanism within a compensatory range [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eExamining microvascular changes through vessel diameter assessment could enhance our understanding of ocular disease pathophysiology[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Previous studies have shown a correlation between the tapering of retinal vessel diameter and elongated axial length, consistent with our findings[\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. A cross-sectional study reported increased wall thickness and the wall-to-lumen ratio increased in myopic eyes, but no significant change in central retinal artery diameter [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], supporting the possibility of retinal vessel remodeling in the myopic eyes. OCTA provided vascular morphologic information based on blood cell movement, potentially offering a more accurate assessment of vascular caliber.\u003c/p\u003e\u003cp\u003eAdditionally, we also evaluated choroidal vascular density and morphology in individuals with myopia. Consistent with prior studies, our findings indicated a reduction in both choroidal vessel density and choroidal thickness as axial length increases [\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Comparable outcomes have been observed in animal models, including mice [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], guinea pigs [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], and marmosets [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. It has been suggested that enhanced choroidal blood perfusion may decelerate the progression of myopia [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e], whereas diminished choroidal blood perfusion could potentially induce myopia in guinea pigs [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. In our investigation, the diameter of the vessels in the choroidal Sattler\u0026rsquo;s and Haller\u0026rsquo;s layers (CSHL) was found to be significantly greater in the high myopia group compared to the low myopia group, and this increase was positively correlated with axial length. The underlying mechanisms responsible for vascular dilation in the myopic choroid remain unclear and may involve complex regulatory processes, including neural control and the regulation of vasoactive molecules [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThis study is subject to several limitations. Firstly, the participants were predominantly young individuals undergoing evaluation for corneal refractive surgery, and the relatively small sample size may have introduced potential bias. Secondly, as a cross-sectional study, this research does not establish a causal relationship between myopia and vascular changes in the retina and choroid. To investigate this causal relationship, further prospective studies with larger sample sizes are necessary.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe progression of myopia leads to reduced retinal vessel diameters and increased retinal branching. Myopia is associated with a reduction in choroidal vessel density, vessel skeleton density, vessel perimeter index, and vessel complexity index, alongside an increase in vascular diameters. Morphological parameters of retina and choroid may offer an additional method for assessing the progression of myopia, and even provide new insights into the pathogenesis of myopia.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e\u003c/p\u003e\u003cdiv class=\"gridtable\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e\u003ccolgroup cols=\"3\"\u003e\u003c/colgroup\u003e\u003cthead\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSS-OCTA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eSwept-source optical coherence tomography angiography\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCSHL\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eChoroidal Sattler’s and Haller’s layers\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSE\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eSpherical equivalents\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eST\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eSupratemporal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eSuperior\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSN\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eSupranasal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eTemporal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eCentral macular area\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eN\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eNasal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eInferotemporal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eInferior\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIN\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eInferonasal\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eLow myopia group\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eModerate myopia\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eHigh myopia\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eIOP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eIntraocular pressure\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAL\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eAxial length\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eMale\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVDI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eVessel diameter index\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSVC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eSuperficial vascular complex\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDVC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eDeep vascular complex\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCCP\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eChoroidal capillary plexus\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/table\u003e\u003c/div\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was conducted at Tianjin Eye Hospital. Ethical approval was obtained from the Medical Ethics Committee of Tianjin Eye Hospital (YK-2023071). This study adhered to the Declaration of Helsinki. Informed consent was obtained from participants prior to the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo datasets were generated or analysed during the current study.\u0026nbsp;The data supporting this study's findings are available from the corresponding authors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the National Natural Science Foundation of China (82160205); grant 2021D01F46 from the Xinjiang Autonomous Region Science Foundation of China, grant YKZD2003 from the Tianjin Eye Hospital; and Tianjin Key Medical Discipline (Specialty) Construction Project (No. TJYXZDXK-016A, No. TJYXZDXK-037A).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors’ contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eW.C. and X.Z. contributed to the direction and guidance of this work. Research Design: W.C. and B.L. Statistical analysis: B.L., Y.Z., K.Y., and C.L. Drafting of the manuscript: B.L. and Y.Z. Revision of the manuscript: W.C. and X.Z. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eXiaomin, Zhang and Wei Chen are co-corresponding authors\u003cstrong\u003e.\u003c/strong\u003e The authors appreciate Editage (www.editage.cn) for the English language editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eORCID IDs\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBing Li https://orcid.org/0000-0003-3505-4909\u003c/p\u003e\n\u003cp\u003eYimeng Zhang https://orcid.org/0009-0007-0171-1006\u003c/p\u003e\n\u003cp\u003eXiaomin Zhang https://orcid.org/0000-0003-4898-4152\u003c/p\u003e\n\u003cp\u003eWei Chen https://orcid.org/0000-0003-3505-4909\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBaird PN, Saw SM, Lanca C, Guggenheim JA, Smith Iii EL, Zhou X, Matsui KO, Wu PC, Sankaridurg P, Chia A\u003cem\u003e et al\u003c/em\u003e: \u003cstrong\u003eMyopia\u003c/strong\u003e. 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(1552-5783 (Electronic)).\u003c/li\u003e\n\u003cli\u003eZhou X, Zhang S, Zhang G, Chen Y, Lei Y, Xiang J, Xu R, Qu J, Zhou X: \u003cstrong\u003eIncreased Choroidal Blood Perfusion Can Inhibit Form Deprivation Myopia in Guinea Pigs\u003c/strong\u003e. \u003cem\u003eInvest Ophthalmol Vis Sci \u003c/em\u003e2020, \u003cstrong\u003e61\u003c/strong\u003e(13):25.\u003c/li\u003e\n\u003cli\u003eJeong H, Lee D, Jiang X, Negishi K, Tsubota K, Kurihara T: \u003cstrong\u003eTopical Application of Bunazosin Hydrochloride Suppresses Myopia Progression With an Increase in Choroidal Blood Perfusion\u003c/strong\u003e. \u003cem\u003eInvest Ophthalmol Vis Sci \u003c/em\u003e2023, \u003cstrong\u003e64\u003c/strong\u003e(14):15.\u003c/li\u003e\n\u003cli\u003eZhou X, Zhang S, Yang F, Yang Y, Huang Q, Huang C, Qu J, Zhou X: \u003cstrong\u003eDecreased Choroidal Blood Perfusion Induces Myopia in Guinea Pigs\u003c/strong\u003e. \u003cem\u003eInvest Ophthalmol Vis Sci \u003c/em\u003e2021, \u003cstrong\u003e62\u003c/strong\u003e(15):30.\u003c/li\u003e\n\u003cli\u003eReiner A, Fitzgerald MEC, Del Mar N, Li C: \u003cstrong\u003eNeural control of choroidal blood flow\u003c/strong\u003e. \u003cem\u003eProg Retin Eye Res \u003c/em\u003e2018, \u003cstrong\u003e64\u003c/strong\u003e.\u003c/li\u003e\n\u003cli\u003eFitzgerald MEC, Tolley E, Jackson B, Zagvazdin YS, Cuthbertson SL, Hodos W, Reiner A: \u003cstrong\u003eAnatomical and functional evidence for progressive age-related decline in parasympathetic control of choroidal blood flow in pigeons\u003c/strong\u003e. \u003cem\u003eExp Eye Res \u003c/em\u003e2005, \u003cstrong\u003e81\u003c/strong\u003e(4):478-491.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"axial length, vessel density, vessel diameter index, vascular morphology, myopia, OCTA","lastPublishedDoi":"10.21203/rs.3.rs-7004115/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7004115/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e\u003cp\u003eThis study aims to evaluate changes in retinal and choroidal vascular morphology in young adults with myopia using swept-source optical coherence tomography angiography (SS-OCTA).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eWe conducted comprehensive ophthalmic examinations, obtained SS-OCTA scans (12 \u0026times; 12 mm\u003csup\u003e2\u003c/sup\u003e), and documented the clinical characteristics of the participants. Eyes were categorized into low, moderate, and high myopia groups based on spherical equivalent refraction. Average vessel density and morphological parameters were quantitatively analyzed using a semi-automated MATLAB program. Vessel area density was further assessed across nine grids using angiography analysis software.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThe retinal vessel diameter index was significantly lower in the high myopia group than that in the low and moderate myopia groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.021 and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.029, respectively), and showed an inverse correlation with axial length (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The retinal vessel complexity index was significantly higher in the high myopia group than that in the low myopia group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.008), and positively correlated with axial length (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001). No significant differences were observed in retinal average vessel density among the three groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.491). In addition, choroidal average vessel density, vessel skeleton density, vessel perimeter index, and vessel complexity index were reduced in the high myopia group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.004, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.007, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.022, and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.037 respectively). The vessel diameter index of choroidal Sattler\u0026rsquo;s and Haller\u0026rsquo;s layers (CSHL) was notably higher in the high myopia group than that in the low myopia group (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.021), demonstrating a positive correlation with axial length (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eAs axial length increases, modifications in retinal vascular morphological parameters, such as diminished retinal vessel diameters and enhanced retinal branching, are observed to precede alterations in the average retinal vessel density. Additionally, in cases of high myopia, significant changes are evident in both choroidal vessel density and vascular morphology.\u003c/p\u003e","manuscriptTitle":"Vascular Morphology of the Retina and Choroid in Young Adults with Myopia Based on Optical Coherence Tomography Angiography","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-11 10:48:58","doi":"10.21203/rs.3.rs-7004115/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ca01525f-6d3e-4935-9c9b-23b068c3cd68","owner":[],"postedDate":"August 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-29T07:23:40+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-11 10:48:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7004115","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7004115","identity":"rs-7004115","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}