Aim To examine the correlation of best-corrected visual acuity (BCVA) with intercapillary area (ICA) measured from optical coherence tomography angiography (OCT-A) in patients with diabetes, and to compare the strength of associations between BCVA with ICA and other OCT-A metrics.
Methods A cross-sectional study involved 447 eyes from 299 patients with diabetes. All participants underwent OCT-A with a swept-source OCT (Triton DRI-OCT, Topcon, Tokyo, Japan). An automated customised MATLAB programme was used to quantify ICA (the mean of the 10 largest areas including foveal avascular zone (FAZ) area (ICA10_FAZ) and excluding FAZ area (ICA10_excFAZ)) and other OCT-A metrics (FAZ area, FAZ circularity and vessel density) from the macular OCT-A images. BCVA was measured using Snellen chart for the patients and then converted to logarithm of the minimum angle of resolution (logMAR) VA. We further defined ‘good VA’ as Snellen >0.7 and ‘poor VA’ as Snellen ≤0.7 as a binary VA outcome for logistic regression analysis.
Results In univariate regression analysis, increased ICA10_FAZ and ICA10_excFAZ were significantly correlated with logMAR (p values <0.05). In multivariate regression analysis, only the association between ICA10_FAZ and logMAR persisted (β=0.103, p=0.024). In multivariable logistic regression analysis, increased ICA10_FAZ (OR=1.300, 95% CI 1.076 to 1.679, p=0.044) and FAZ circularity (OR=1.285, 95% CI 1.031 to 1.603, p=0.026) showed significant associations with poor VA.
Conclusions Increased ICA measured from OCT-A, describing enlargement of capillary rarefaction or closure at macular area, is independently associated with BCVA, suggesting that ICA is a potential marker to quantify retinal microvascular abnormalities relating to vision among individuals with diabetes.
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Funding CUHK Direct Grant (Reference No. 2015.1.046).
Competing interests None declared.
Ethics approval Research Ethnic Committee, Kowloon Central/Kowloon East, Hong Kong.
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent Parental/guardian consent obtained.
Contributors CYC, conception and design and guarantor of this work; FYT, ZS, RW, JL, CKC, SM, DSN: acquisition of data; FYT, AL, ZS, TL, SS: analysis and interpretation of data; FYT and CYC: drafting the article or revising it critically for important intellectual content; CYC, CCT: final approval of the version to be published.
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