Abstract
PurposeTo assess cone density as a marker of early signs of retinopathy in patients with type II diabetes mellitus.MethodsAn adaptive optics (AO) retinal camera (rtx1™; Imagine Eyes, Orsay, France) was used to acquire images of parafoveal cones from patients with type II diabetes mellitus with or without retinopathy and from healthy controls with no known systemic or ocular disease. Cone mosaic was captured at 0° and 2°eccentricities along the horizontal and vertical meridians. The density of the parafoveal cones was calculated within 100×100-μm squares located at 500-μm from the foveal center along the orthogonal meridians. Manual corrections of the automated counting were then performed by 2 masked graders. Cone density measurements were evaluated with ANOVA that consisted of one between-subjects factor, stage of retinopathy and the within-subject factors. The ANOVA model included a complex covariance structure to account for correlations between the levels of the within-subject factors.ResultsTen healthy participants (20 eyes) and 25 patients (29 eyes) with type II diabetes mellitus were recruited in the study. The mean (± standard deviation [SD]) age of the healthy participants (Control group), patients with diabetes without retinopathy (No DR group), and patients with diabetic retinopathy (DR group) was 55 ± 8, 53 ± 8, and 52 ± 9 years, respectively. The cone density was significantly lower in the moderate nonproliferative diabetic retinopathy (NPDR) and severe NPDR/proliferative DR groups compared to the Control, No DR, and mild NPDR groups (P < 0.05). No correlation was found between cone density and the level of hemoglobin A1c (HbA1c) or the duration of diabetes.ConclusionsThe extent of photoreceptor loss on AO imaging may correlate positively with severity of DR in patients with type II diabetes mellitus. Photoreceptor loss may be more pronounced among patients with advanced stages of DR due to higher risk of macular edema and its sequelae.
Highlights
The underlying pathophysiological processes that result in visual loss in diabetic retinopathy (DR) are yet to be completely understood.[1]
Cone density measurements were evaluated with analysis of variance (ANOVA) that consisted of one between-subjects factor, stage of retinopathy and the within-subject factors
Ten healthy participants (20 eyes) and 25 patients (29 eyes) with type II diabetes mellitus were recruited in the study
Summary
The underlying pathophysiological processes that result in visual loss in diabetic retinopathy (DR) are yet to be completely understood.[1]. Imaging systems based on AO principles correct for aberration arising from various refractive surfaces within the eye. Such correction leads to a high-resolution imaging that allows noninvasive in vivo visualization of the retinal cells, which has been only feasible in histological studies until recently.[13] So far, AO has been used to study the state of various cellular and vascular structures of the retina, in particular photoreceptors, in both health and disease.[14,15,16]The index study aims to assess cone density as a marker of early signs of retinopathy in patients with type II diabetes mellitus
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
