Study Documents Impact of Ethnicity, Sex and Age on Retinal Vascular Morphology

Retinal measurements vary significantly across sex and different ethnicities; for example, on average, men have greater overall macular and inner retinal thickness, while women frequently present with thicker retinal nerve fiber layers. The above forest plot from the paper shows the differences in the normative ranges of select retinal morphometric features across the ethnicities. Photo: Injety R, et al. Ophthalmol Sci. May 7, 2026. Click image to enlarge. In a recent study published in Ophthalmology Science, deep learning analysis of healthy UK Biobank participants found significant ethnic, age-related and sex-based differences in retinal vascular morphology, establishing one of the first ethnicity-stratified normative retinal datasets for oculomic biomarker research. The researchers analyzed retinal fundus images from 6,843 adults with no diagnosed medical conditions to define baseline retinal vascular measurements across ethnic groups.The study used a publicly available deep learning tool to evaluate retinal vascular features from UK Biobank color fundus photographs. The researchers measured vessel caliber, fractal dimension, vessel density and tortuosity and optic nerve head parameters including cup-to-disc ratio. Participants ranged from 40 to 70 years of age, with a mean of 53.5 years, and the cohort was 50.1% male. 91.1% of participants were white, 2.6% were Asian, 2.4% were Black and smaller proportions identified as Chinese or other backgrounds.The researchers found that retinal vascular complexity consistently declined with age. Older participants demonstrated lower fractal dimension, reduced vessel density and narrower retinal vessels. Participants aged 70 years and up showed significantly reduced global fractal dimension, indicating a loss of vascular branching complexity. Vessel density also dropped substantially in adults aged 60 to 69.Participants’ ethnicities were also a strong influence on retinal measurements. Chinese participants showed the highest vessel density and fractal dimension, suggesting a denser and more complex retinal microvascular network compared with white participants. Chinese and Black participants also exhibited larger optic disc and cup dimensions and wider retinal venules. In the study, the authors noted that “these findings establish a foundation for applying retinal vascular biomarkers in multi-ethnic clinical and population research.”They also mentioned the relevance of sex differences, as male participants tended to have narrower vessels and lower tortuosity values than female ones, although optic nerve head differences by sex were small after statistical correction. BMI did not significantly affect retinal morphometric features.The authors noted that these normative retinal measurements may improve future precision-medicine approaches for predicting cardiovascular, neurovascular and systemic disease risk using retinal imaging biomarkers.Click here for the source. Injety R, Hunt C, Yoon H, et al. Ethnicity-stratified normative retinal vascular features from the UK Biobank using deep learning. Ophthalmol Sci. May 7, 2026. [Epub ahead of print]. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.