Distribution of different sized ocular surface vessels in diabetics and normal individuals

Abstract

Purpose:To compare the distribution of different sized vessels using digital photographs of the ocular surface of diabetic and normal individuals.Methods:In this cross-sectional study, red-free conjunctival photographs of diabetic and normal individuals, aged 30-60 years, were taken under defined conditions and analyzed using a Radon transform-based algorithm for vascular segmentation. The image areas occupied by vessels (AOV) of different diameters were calculated. The main outcome measure was the distribution curve of mean AOV of different sized vessels. Secondary outcome measures included total AOV and standard deviation (SD) of AOV of different sized vessels.Results:Two hundred and sixty-eight diabetic patients and 297 normal (control) individuals were included, differing in age (45.50 ± 5.19 vs. 40.38 ± 6.19 years, P < 0.001), systolic (126.37 ± 20.25 vs. 119.21 ± 15.81 mmHg, P < 0.001) and diastolic (78.14 ± 14.21 vs. 67.54 ± 11.46 mmHg, P < 0.001) blood pressures. The distribution curves of mean AOV differed between patients and controls (smaller AOV for larger vessels in patients; P < 0.001) as well as between patients without retinopathy and those with non-proliferative diabetic retinopathy (NPDR); with larger AOV for smaller vessels in NPDR (P < 0.001). Controlling for the effect of confounders, patients had a smaller total AOV, larger total SD of AOV, and a more skewed distribution curve of vessels compared to controls.Conclusion:Presence of diabetes mellitus is associated with contraction of larger vessels in the conjunctiva. Smaller vessels dilate with diabetic retinopathy. These findings may be useful in the photographic screening of diabetes mellitus and retinopathy.

An Analysis of the Areas Occupied by Vessels in the Ocular Surface of Diabetic Patients: An Application of a Nonparametric Tilted Additive Model

“…The AOV represents a ratio of the image pixels occupied by vessels of different diameters to the total pixels in the picture. More details about the data gathering process are available in [ 12 ]. We took the AOV as the outcome variable and evaluated the associations among the predictors and the outcome using the TAM.…”

“…Hence, we explore whether the microvasculature of the ocular surface, which is easier to see and photograph, is affected by diabetes or otherwise. In a previous paper [ 12 ], we showed that the microvasculature of the ocular surface is affected by development of diabetes. That study used a regression model, which did not show any effect of different predictors on the ocular surface vessels.…”

Functional slit lamp biomicroscopy metrics correlate with cardiovascular risk

“…8 Imaging via this technique is fast and easy, while processing of the images is a lengthy process which could be sped up with more automation, as demonstrated by Khansari et al 9 Several studies have found correlations between conjunctival microcirculation and the vessels in the rest of the body. 3, 8, 10–13 For example, individuals with type 2 diabetes were found to have wider conjunctival vessel diameters and more abnormal microvascular distribution than healthy controls. 12, 13…”

Rubeosis faciei diabeticorum is not associated with oxidative stress and skin autofluorescence

“…NF-κB enhances VEGF expression and triggers retinal neovascularization, which is a feature of proliferative diabetic retinopathy 21 . Changes in the conjunctival microvasculature have also been noted in patients with diabetic retinopathy 22, 23…”