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Purpose: To examine the association between retinal vascular caliber and early age-related macular degeneration (AMD) in an Indian population. Methods: A total of 3112 Indian participants aged ≥40 years from the population-based Singapore Indian Eye Study who had data available on retinal vascular caliber measurements and AMD status were included. Retinal arteriolar and venular calibers were measured from digital photographs using computer-assisted software according to a standardized protocol. Images of the macular region were graded according to the modified Wisconsin age-related maculopathy grading system. Right eyes were selected for analyses. Binary logistic regression models were used to assess the association, adjusting for age, sex, systolic blood pressure, total cholesterol, random blood glucose, body mass index, and the companion retinal vascular caliber. Results: A total of 107 participants (3.4%) were diagnosed with early AMD. Neither arteriolar nor venular caliber was related to AMD. For early AMD, the age-, sex-, and companion retinal vascular caliber-adjusted odds ratio (OR) per standard deviation (SD) decrease in arteriolar caliber was 0.95 (95% CI 0.84-1.31; p = 0.671), and per SD increase in venular caliber was OR: 0.96 (95% CI: 0.77-1.20); p = 0.714. No trend was found after categorizing retinal vascular calibers into quartiles. Multivariate adjustment and stratified analyses did not alter these results. Conclusion: Retinal vascular calibers were not related to early AMD among Indian participants. These findings differ from those of several previous studies performed in Caucasian and Asian populations. [ABSTRACT FROM AUTHOR]

Purpose: Dilation of retinal vessels in response to diffuse luminance flicker may reflect endothelial function. Although this has previously been shown to be reproducible in whites, there have been no similar data in Asians. We assess the reproducibility of repeated measurements of this response in Asians. Material and Methods: Healthy Asians ( n = 33) with normal vision and no history of glaucoma, age-related macular degeneration, cataract, or retinal arterial/venous occlusion participated in this study. Repeated measures from the same subjects were taken 30–60 min apart using the Dynamic Vessel Analyser (DVA, IMEDOS, Jena, Germany). Modification was made to the shape of the light source for Asian participants. Correlations of the first and second measures were assessed using Pearson correlation ( R2), and agreement between the two measures was shown using Bland–Altman plots. Results: After modification to the shape of the light source, almost perfect correlation was found between the 1st and 2nd measurements of baseline arteriolar ( R2 = 0.95) and venular diameters ( R2 = 0.98) of arteriolar maximum dilation ( R2 = 0.85). Substantially high correlation between the 1st and 2nd measurements of venular maximum dilation was found ( R2 = 0.80). Conclusions: Measurements of the dilation response of retinal vessels to diffuse luminance flicker an Asian sample using the DVA show high reproducibility for repeated measures over a short period of time. Such measurements may allow non-invasive quantification of endothelial function to study its association with systemic and ocular diseases. [ABSTRACT FROM AUTHOR]