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Optical coherence tomography (OCT) is a non-invasive optical imaging modality, which provides rapid, high-resolution and cross-sectional morphology of macular area and optic nerve head for diagnosis and managing of different eye diseases. However, interpreting OCT images requires experts in both OCT images and eye diseases since many factors such as artefacts and concomitant diseases can affect the accuracy of quantitative measurements made by post-processing algorithms. Currently, there is a growing interest in applying deep learning (DL) methods to analyse OCT images automatically. This review summarises the trends in DL-based OCT image analysis in ophthalmology, discusses the current gaps, and provides potential research directions. DL in OCT analysis shows promising performance in several tasks: (1) layers and features segmentation and quantification; (2) disease classification; (3) disease progression and prognosis; and (4) referral triage level prediction. Different studies and trends in the development of DL-based OCT image analysis are described and the following challenges are identified and described: (1) public OCT data are scarce and scattered; (2) models show performance discrepancies in real-world settings; (3) models lack of transparency; (4) there is a lack of societal acceptance and regulatory standards; and (5) OCT is still not widely available in underprivileged areas. More work is needed to tackle the challenges and gaps, before DL is further applied in OCT image analysis for clinical use., (© 2023 Royal Australian and New Zealand College of Ophthalmologists.)

Objective: To determine the longitudinal associations between retinal vascular profile (RVP) and four major cardiometabolic diseases; and to quantify the predictive improvements when adding RVP beyond traditional risk factors in individuals with diabetes., Methods: Subjects were enrolled from the Singapore Epidemiology of Eye Disease (SEED) study, a multi-ethnic population-based cohort. Four incident cardiometabolic diseases, calculated over a ~ 6-year period, were considered: cardiovascular disease (CVD), hypertension (HTN), diabetic kidney disease (DKD), and hyperlipidemia (HLD). The RVP-vessel tortuosity, branching angle, branching coefficient, fractal dimension, vessel caliber, and DR status-was characterized at baseline using a computer-assisted program. Traditional risk factors at baseline included age, gender, ethnicity, smoking, blood pressure (BP), HbA1c, estimated glomerular filtration rate (eGFR), or cholesterol. The improvements in predictive performance when adding RVP (compared with only traditional risk factors) was calculated using several metrics including area under the receiver operating characteristics curve (AUC) and net reclassification improvement (NRI)., Results: Among 1770 individuals with diabetes, incidences were 6.3% (n = 79/1259) for CVD, 48.7% (n = 166/341) for HTN, 14.6% (n = 175/1199) for DKD, and 59.4% (n = 336/566) for HLD. DR preceded the onset of CVD (RR 1.85[1.14;3.00]) and DKD (1.44 [1.06;1.96]). Narrower arteriolar caliber preceding the onset of HTN (0.84 [0.72;0.99]), and changes in arteriolar branching angle preceded the onset of CVD (0.78 [0.62;0.98]) and HTN (1.15 [1.03;1.29]). The largest predictive improvement was found for HTN with AUC increment of 3.4% (p = .027) and better reclassification of 11.4% of the cases and 4.6% of the controls (p = .008)., Conclusion: We found that RVPs improved the prediction of HTN in individuals with diabetes, but add limited information for CVD, DKD, and HLD predictions., (© 2022 John Wiley & Sons Ltd.)

Background: Screening for chronic kidney disease is a challenge in community and primary care settings, even in high-income countries. We developed an artificial intelligence deep learning algorithm (DLA) to detect chronic kidney disease from retinal images, which could add to existing chronic kidney disease screening strategies., Methods: We used data from three population-based, multiethnic, cross-sectional studies in Singapore and China. The Singapore Epidemiology of Eye Diseases study (SEED, patients aged ≥40 years) was used to develop (5188 patients) and validate (1297 patients) the DLA. External testing was done on two independent datasets: the Singapore Prospective Study Program (SP2, 3735 patients aged ≥25 years) and the Beijing Eye Study (BES, 1538 patients aged ≥40 years). Chronic kidney disease was defined as estimated glomerular filtration rate less than 60 mL/min per 1·73m 2 . Three models were trained: 1) image DLA; 2) risk factors (RF) including age, sex, ethnicity, diabetes, and hypertension; and 3) hybrid DLA combining image and RF. Model performances were evaluated using the area under the receiver operating characteristic curve (AUC)., Findings: In the SEED validation dataset, the AUC was 0·911 for image DLA (95% CI 0·886 -0·936), 0·916 for RF (0·891-0·941), and 0·938 for hybrid DLA (0·917-0·959). Corresponding estimates in the SP2 testing dataset were 0·733 for image DLA (95% CI 0·696-0·770), 0·829 for RF (0·797-0·861), and 0·810 for hybrid DLA (0·776-0·844); and in the BES testing dataset estimates were 0·835 for image DLA (0·767-0·903), 0·887 for RF (0·828-0·946), and 0·858 for hybrid DLA (0·794-0·922). AUC estimates were similar in subgroups of people with diabetes (image DLA 0·889 [95% CI 0·850-0·928], RF 0·899 [0·862-0·936], hybrid 0·925 [0·893-0·957]) and hypertension (image DLA 0·889 [95% CI 0·860-0·918], RF 0·889 [0·860-0·918], hybrid 0·918 [0·893-0·943])., Interpretation: A retinal image DLA shows good performance for estimating chronic kidney disease, underlying the feasibility of using retinal photography as an adjunctive or opportunistic screening tool for chronic kidney disease in community populations., Funding: National Medical Research Council, Singapore., (Copyright © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Importance: Asian Indians are the fastest growing migration groups in the world. Studies evaluating the impact of migration on disease outcomes in this population are rare., Background: We describe the methodology of the Singapore Indian Eye Study-2 (SINDI-2) aimed to evaluate the impact of migration status on diabetic retinopathy and other major age-related eye diseases in Asian Indians living in an urban environment., Design: Population-based cohort study., Participants: A total of 2200 adults had participated in baseline SINDI (2007-2009, mean age [range] = 57.8 [42.7-84.1] years) and SINDI-2 (2013-2015, 56.5 [48.4-90.2] years)., Methods: Participants were classified as 'first generation' if they were Indian residents born outside of Singapore and as 'second-generation' immigrants (59.7% in SINDI vs. 63.6% in SINDI-2) if they were born in Singapore., Main Outcome Measures: Response rate, participant characteristics and prevalence of systemic diseases were stratified by migration status., Results: Of the 2914 eligible SINDI participants invited to participate, 2200 participated in SINDI-2 (response rate of 75.2%). In both SINDI and SINDI-2, compared with first-generation immigrants, second-generation immigrants were younger, less likely to have income <1000 SGD, had lower levels of pulse pressure, higher levels of high-density lipoprotein cholesterol, had lower prevalence of hypertension and chronic kidney disease and had higher prevalence of current smoking and obesity (all P < 0.05)., Conclusions and Relevance: In both SINDI and SINDI-2, second-generation immigrants had lower prevalence of cardiovascular risk factors except smoking and obesity compared with first-generation immigrants. The final report will confirm if these differences between generations are evident with regard to eye diseases., (© 2017 Royal Australian and New Zealand College of Ophthalmologists.)

We investigated the relationship of visual impairment (VI) and age-related eye diseases with mortality in a prospective, population-based cohort study of 3,280 Malay adults aged 40-80 years between 2004-2006. Participants underwent a full ophthalmic examination and standardized lens and fundus photographic grading. Visual acuity was measured using logMAR chart. VI was defined as presenting (PVA) and best-corrected (BCVA) visual acuity worse than 0.30 logMAR in the better-seeing eye. Participants were linked with mortality records until 2012. During follow-up (median 7.24 years), 398 (12.2%) persons died. In Cox proportional-hazards models adjusting for relevant factors, participants with VI (PVA) had higher all-cause mortality (hazard ratio[HR], 1.57; 95% confidence interval[CI], 1.25-1.96) and cardiovascular (CVD) mortality (HR 1.75; 95% CI, 1.24-2.49) than participants without. Diabetic retinopathy (DR) was associated with increased all-cause (HR 1.70; 95% CI, 1.25-2.36) and CVD mortality (HR 1.57; 95% CI, 1.05-2.43). Retinal vein occlusion (RVO) was associated with increased CVD mortality (HR 3.14; 95% CI, 1.26-7.73). No significant associations were observed between cataract, glaucoma and age-related macular degeneration with mortality. We conclude that persons with VI were more likely to die than persons without. DR and RVO are markers of CVD mortality.

The retinal vasculature provides a unique window to assess vascular health noninvasively and directly in vivo. Advances in fundus photography and retinal image analysis techniques have enabled the objective and accurate assessment of quantitative retinal vascular caliber measurement. Over the last decade, large population-based studies have shown that retinal vascular calibers are associated with a wide range of subclinical (e.g. atherosclerosis, inflammation and endothelial dysfunction) and clinical cardiovascular diseases (hypertension, diabetes mellitus, stroke, kidney and heart diseases). However, while retinal image analysis provided exciting possibilities to study the pathogenesis of these diseases, its direct applicability in a clinical setting as a 'test' to predict cardiovascular diseases is yet to be established, particularly within the context of being used as a population screening tool. Nevertheless, with continual development of retinal imaging techniques and newer understanding of the clinical significance of these retinal changes, there remains scope for the development of retinal vascular caliber measurements as a biomarker for vascular disease risk assessment in targeted areas and patient subgroups (e.g. patients with diabetes, suspected hypertension and stroke)., (Copyright © 2012 S. Karger AG, Basel.)

Purpose: To examine the influence of a range of cardiovascular risk factors and ocular conditions on retinal vascular fractal dimension in the Singapore Malay Eye Study., Design: Population-based cross-sectional study., Methods: Fractal analysis of the retinal vessels is a method to quantify the global geometric complexity of the retinal vasculature. Retinal vascular fractal dimension (D(f)) and caliber were measured from retinal photographs using a computer-assisted program. D(f) and arteriolar caliber were combined to form a retinal vascular optimality score (ranging from 0 to 3). Data on cardiovascular and ocular factors were collected from all participants based on a standardized protocol., Results: Two thousand nine hundred thirteen (88.8% of 3280 participants) persons had retinal photographs of sufficient quality for the measurement. The mean D(f) was 1.405 (standard deviation, 0.046; interquartile range, 1.243 to 1.542). In the multiple linear regression analysis, after controlling for gender, serum glucose, intraocular pressure, anterior chamber depth, and retinal vascular caliber, smaller D(f) was associated independently with older age (standardized regression coefficient [sβ] = -0.311; P < .001), higher mean arterial blood pressure (sβ = -0.085; P < .001), a more myopic spherical equivalent (sβ = 0.152; P < .001), and presence of cataract (sβ = -0.107; P < .001). Retinal vascular optimality score was associated significantly with higher mean arterial blood pressure (P > .001 for trend)., Conclusions: Age, blood pressure, refractive error, and lens opacity had significant influence on retinal vascular fractal measurements. A new score of retinal vascular optimality combining fractals and caliber showed strong association with blood pressure. Quantitative analysis of retinal vasculature therefore may provide additional information on microvascular architecture and optimality., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objective: To describe the associations of visual impairment and major age-related eye diseases with cognitive function in an older Asian population., Methods: A population-based, cross-sectional study of 1179 participants aged 60 to 80 years from the Singapore Malay Eye study was conducted. Visual acuity was measured using the logMAR vision chart. Cataract and age-related macular degeneration were graded using the Wisconsin Cataract Grading System and the Wisconsin Age-Related Maculopathy Grading System, respectively. Glaucoma was diagnosed using the International Society Geographical and Epidemiological Ophthalmology criteria. Diabetic retinopathy was graded using the modified Airlie House classification system. Cognitive dysfunction was defined as a locally validated Abbreviated Mental Test using education-based cutoff scores., Results: After adjusting for age, sex, education level, income, and type of housing, persons with visual impairment before refractive correction (odds ratio [OR]=2.59; 95% CI, 1.89-3.56) or after refractive correction (OR=1.96; 95% CI, 1.27-3.02) and those with visual impairment due to cataract (OR=2.75; 95% CI, 1.35-5.63) were more likely to have cognitive dysfunction. Only moderate to severe diabetic retinopathy was independently associated with cognitive dysfunction (OR=5.57; 95% CI, 1.56-19.91) after controlling for concurrent age-related eye diseases. No significant independent associations were observed between cataract, age-related macular degeneration, or glaucoma and cognitive dysfunction., Conclusions: Older persons with visual impairment, particularly those with visual impairment due to cataract, were more likely to have cognitive dysfunction. Furthermore, among the major age-related eye diseases, only diabetic retinopathy was associated with cognitive dysfunction.

Choroidal thickness is associated with many ocular conditions, interchangeability among different generations of optical coherence tomography is therefore important for both research purpose and clinical application. Hence, we compared choroidal thickness measurements between spectral-domain optical coherence tomography (SD-OCT) and swept-source optical coherence tomography (SS-OCT) in healthy paediatric eyes. A total of 114 children from the population-based Hong Kong Children Eye Study with mean age of 7.38 ± 0.82 years were included. Choroidal thickness of the right eye was measured by both devices. The central foveal choroidal thickness (CFCT) measured by SD-OCT and SS-OCT was 273.24 ± 54.29 μm and 251.84 ± 47.12 μm respectively. Inter-device correlation coefficient was 0.840 (95% CI 0.616–0.918). However, choroidal thickness obtained by SD-OCT was significantly thicker than that measured by SS-OCT with a mean difference of 21.40 ± 33.13 μm (P < 0.001). Bland–Altman limit of agreement on the relative difference scale for SD-OCT/SS-OCT was 86.33 μm. Validated conversion equation for translating SD-OCT CFCT measurement into SS-OCT was SS-OCT = 35.261 + 0.810 × SD-OCT. In conclusion, intra-class correlation coefficient (ICC) shows an acceptable agreement between SD-OCT and SS-OCT, however, there was a significant inter-device difference of choroidal thickness measurements in normal children eyes. Therefore, the measurements are not interchangeable. [ABSTRACT FROM AUTHOR]

Purpose: Visual field (VF) sensitivity is known to be age-dependent, but there is a paucity of evidence on whether it is gender-dependent. We therefore investigated the effect of gender on VF sensitivity. Methods: An observational study involving 491 adults from the population-based Singapore Chinese Eye Study (SCES). Study participants underwent a comprehensive and standardised ocular examination and VF assessment on the Humphrey Field Analyzer II (Carl Zeiss Meditec, Inc., Dublin, CA, USA). The effect of gender on the mean deviation (MD) and pattern standard deviation (PSD) was analysed with linear regression models. Results: The mean age was 52.9 ± 5.9 years, and 229 (46.6%) participants were women. A total of 800 reliable VFs from 655 healthy eyes without visual impairment, glaucoma and significant cataract were included. The mean (± standard deviation) MD was −0.45 ± 1.01 dB in men, and −0.84 ± 1.20 dB in women. The MD [95% confidence interval] was 0.28 [−0.44 to −0.12] dB lower in females compared to males (P = 0.001) after adjusting for reliability indices, degree of lens opacity, and other potential confounders. The PSD was not significantly different between the genders. Conclusions: In the SCES, the population-average of the central VF sensitivity was significantly lower in women compared to men by a small amount (0.28 dB). This effect was observed in healthy eyes, and was not explained by multiple potential confounders. Hence, this likely represents a physiological gender-based difference that is unaccounted for in standard automated perimetry. Further studies in other populations would be needed to corroborate our findings. [ABSTRACT FROM AUTHOR]

Aims: To determine the diagnostic performance of macular ganglion cell-inner plexiform layer (GCIPL) thickness measured by spectral-domain optical coherence tomography (SD-OCT) for glaucoma detection in a Chinese population in comparison with optic nerve head (ONH) and retinal nerve fiber layer (RNFL) parameters measured by both SD-OCT and Heidelberg Retina Tomography 3 (HRT-3). Methods: Adults aged 40 to 80 years were recruited from the population-based study (n = 3353, response rate 72.8%). Macular cube 200x200 scan was performed with Cirrus SD-OCT (version 6.0, Carl Zeiss Meditec Inc, Dublin, CA) for GCIPL thickness measurement. ONH and RNFL imaging was performed with Cirrus SD-OCT and HRT-3 (Heidelberg Engineering, Heidelberg, Germany). Glaucoma was defined according to International Society for Geographical and Epidemiological Ophthalmology criteria. Results: In total, 86 eyes of 60 subjects with glaucoma and 1709 eyes of 1001 non-glaucoma participants were included. The best performing parameters for Cirrus SD-OCT GCIPL, Cirrus SD-OCT ONH and HRT-3 were minimum GCIPL thickness (Area under receiver-operating curve [AUC] = 0.89, 95% CI 0.83–0.95), vertical cup-disc ratio (CDR) (AUC = 0.94, 0.91–0.98) and vertical CDR (AUC = 0.86, 0.81–0.92), respectively. At 85% specificity, vertical CDR measured using Cirrus OCT ONH scan showed the highest sensitivity (88.64%, 95% CI 75.4–96.2) compared to minimum GCIPL thickness with sensitivity of 60.53% (95% CI 46.4–73.0) (p<0.001). Inferior RNFL thickness (AUC = 0.84, 95% CI 0.91–0.97) measured by Cirrus SD-OCT was also superior to Cirrus SD-OCT GCIPL (p<0.007). Conclusions: The diagnostic performance of macular GCIPL scan is inferior compared to vertical CDR measured by Cirrus OCT ONH scan. Cirrus OCT ONH scan showed the best ability in detecting glaucoma in a Chinese population, suggesting it could be a good glaucoma screening tool in an Asian population. [ABSTRACT FROM AUTHOR]

Purpose: To determine the associations of myopia and axial length (AL) with major age-related eye diseases, including age-related macular degeneration (AMD), diabetic retinopathy (DR), age-related cataract, and primary open-angle glaucoma (POAG). Design: Population-based, cross-sectional study. Participants: A total of 3400 Indians (75.6% response rate) aged 40 to 84 years in Singapore. Methods: Refractive error was determined by subjective refraction, and AL was determined by noncontact partial coherence laser interferometry. Age-related macular degeneration and DR were defined from retinal photographs according to the Wisconsin Age-Related Maculopathy Grading System and Airlie House classification system, respectively. Age-related cataract was diagnosed clinically using the Lens Opacity Classification System (LOCS) III system. Glaucoma was defined according to International Society for Geographical and Epidemiological Ophthalmology criteria. Main Outcome Measures: Age-related macular degeneration, DR, age-related cataract, and POAG. Results: Myopic eyes (spherical equivalent [SE] <−0.5 diopter [D]) were less likely to have AMD (early plus late AMD) (odds ratio [OR], 0.45; 95% confidence interval [CI], 0.25–0.79) or DR (OR, 0.68; 95% CI, 0.46–0.98) compared with emmetropic eyes; each millimeter increase in AL was associated with a lower prevalence of AMD (OR, 0.76; 95% CI, 0.65–0.89) and DR (OR, 0.73; 95% CI, 0.63–0.86). Myopic eyes were more likely to have nuclear (OR, 1.57; 95% CI, 1.13–2.20) and posterior subcapsular (OR, 1.73; 95% CI, 1.10–2.72) cataract, but not cortical cataract (P = 0.64); each millimeter increase in AL was associated with a higher prevalence of posterior subcapsular cataract (PSC) (OR, 1.29; 95% CI, 1.07–1.55), but not nuclear (P = 0.77) or cortical (P = 0.39) cataract. Eyes with high myopia (SE <−6.0 D) were more likely to have POAG (OR, 5.90; 95% CI, 2.68–12.97); each millimeter increase in AL was associated with a higher prevalence of POAG (OR, 1.43; 95% CI, 1.13–1.80). Conclusions: Myopic eyes are less likely to have AMD and DR but more likely to have nuclear cataract, PSC, and POAG. The associations of myopia with AMD, DR, and POAG are mostly explained by longer AL. However, the association between myopia and nuclear cataract is explained by lens refraction rather than AL. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. [Copyright &y& Elsevier]

OBJECTIVE--To examine the association between early retinal arteriolar abnormalities and diabetic peripheral neuropathy (DPN). RESEARCH DESIGN AND METHODS--Data from 608 people (aged 40-80 years) with diabetes from the population-based Singapore Malay Eye Study were analyzed. Participants underwent binocular two-field digital retinal photography and quantitative sensory testing. DPN was defined as an abnormal response to a monofilament or neurothesiometer test. Quantitative changes of retinal vascular caliber and arteriolar bifurcation geometry were measured using a computer-based program. Qualitative retinal signs of retinopathy and retinal arteriolar wall signs were graded by standardized methods. RESULTS--DPN was present in 155 people (25.5%). After adjusting for age, sex, diabetes duration, HbA1c, cardiovascular risk factors, antihypertensive medication use, and peripheral arterial disease, people with suboptimal arteriolar caliber (odds ratio 1.94 [95% CI 1.22-3.10]), larger arteriolar branching coefficient (1.58 [1.03-2.42]), diabetic retinopathy (1.82 [1.20-2.75]), and focal arteriolar narrowing (2.92 [1.48-5.76]) were more likely to have DPN. Participants with a greater number of retinal microvascular signs were more likely to have DPN than those without retinal changes (6.11 [2.11-17.71] for two or more signs and 3.47 [1.18-10.21] for one sign compared with none). CONCLUSIONS--Individuals with diabetes with early retinal arteriolar abnormalities are more likely to have DPN, independent of hyperglycemia and major vascular risk factors. These data support the hypothesis that early microvascular dysfunction, evident in the retina, is an independent risk factor for DPN. [ABSTRACT FROM AUTHOR]

To examine the normative profile and determinants of macular ganglion cell-inner plexiform layer (GCIPL) thickness based on spectral-domain OCT (SD-OCT) in a nonglaucoma, multi-ethnic Asian population. Population-based, cross-sectional study. Ethnic Chinese, Malay, and Indian adults aged ≥40 years recruited from the Singapore Epidemiology of Eye Diseases Study. All participants underwent standardized examinations. The GCIPL thickness was measured using Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA). Participants with glaucoma or poor-quality scans were excluded. Eye-specific data were used. Associations of ocular and systemic factors with GCIPL thickness parameters were investigated using multivariable linear regression with generalized estimating equation models to account for correlation between both eyes. GCIPL thickness. A total of 4464 participants (7520 eyes) consisting of 1625 Chinese, 1212 Malay, and 1627 Indian adults contributed to this analysis. Average GCIPL thickness was 82.6±6.1 μm in Chinese, 81.5±6.8 μm in Malays, and 78.0±6.9 μm in Indians (P < 0.001 by analysis of variance). The 5th percentile limit of average GCIPL thickness was 72 μm in Chinese, 70 μm in Malays, and 67 μm in Indians. In multivariable analysis adjusting for age, gender, axial length, presence of cataract, OCT signal strength, disc area, hypertension, diabetes, and hyperlipidemia, eyes of Indians were observed to have 3.43 μm thinner GCIPL on average compared with Chinese (P < 0.001) and 3.36 μm thinner GCIPL compared with Malays (P < 0.001). In addition, older age (per decade; β = −2.51), female (β = −1.57), longer axial length (per mm; β = −1.54), and presence of chronic kidney disease (β = −1.49) were significantly associated with thinner average GCIPL (all P ≤ 0.008). Larger optic disc area (per mm2; β = 0.78; P < 0.001) was associated with thicker GCIPL. These factors were consistently observed to be significant for superior and inferior hemisphere GCIPL thickness. GCIPL thickness profiles were significantly thinner in Indians compared with Chinese and Malays. Our findings further highlight the need of a more refined, ethnic-specific normative database for GCIPL thickness, which in turn may improve the detection and diagnosis of glaucoma in Asians. [ABSTRACT FROM AUTHOR]

To describe variations in retinal nerve fiber layer (RNFL) thickness based on spectral-domain (SD) OCT in a multiethnic Asian population. Population-based, cross-sectional study. Ethnic Chinese, Malay, and Indian adults older than 48 years without glaucoma who were recruited from the Singapore Epidemiology of Eye Diseases Study. All participants underwent standardized systemic and ocular examinations. Retinal nerve fiber layer thickness was measured using SD OCT. Participants with poor-quality scans were excluded. Linear regression models were used to investigate the associations of ocular and systemic factors with average RNFL thickness. Generalized estimating equation models were used to account for correlation between both eyes. Average RNFL thickness. Four thousand four hundred seventy-five participants (8178 eyes) consisting of 1371 Chinese, 1303 Malay, and 1801 Indian adults contributed to this analysis. Average RNFL thickness measured was 95.7±9.6 μm in Chinese participants, 94.9±10.6 μm in Malay participants, and 87.3±10.6 μm in Indian participants (P < 0.001). Multivariate analysis adjusted for age, gender, and ethnicity revealed a reduction in RNFL thickness with increased intraocular pressure and axial length (P < 0.001 for both), as well as a diagnosis of diabetes (P = 0.04); greater RNFL thickness was associated with increased disc area (P < 0.001), signal strength (P < 0.001), and low-density lipoprotein cholesterol (P = 0.02). When these significant variables were taken into account, the average RNFL thickness of Indian participants was significantly thinner compared with Chinese participants (7.45 μm thinner on average [95% confidence interval, 6.75–8.15 μm; P < 0.001]), whereas there was no significant difference in average RNFL thickness between Malay and Chinese participants (P = 0.15). Average and regional RNFL thicknesses were significantly thinner in Indian eyes compared with Chinese and Malay eyes. Results of the study highlight the need to acquire more refined normative data for the comparison of individual patients with others of similar ethnic background while accounting for ocular factors that could influence RNFL thickness. This in turn may improve the sensitivity and specificity of glaucoma detection. [ABSTRACT FROM AUTHOR]