Purpose: This study investigated the associations between the responses of retinal vessels to flickering light and the incidence and progression of diabetic retinopathy (DR).
Methods: A prospective cohort study of adult subjects with diabetes mellitus. The dynamic vessel analyser (DVA) was used to measure retinal vascular dilatation in response to diffuse illuminance flicker. Diabetic retinopathy was graded from retinal photography at baseline and at 1 year. Incident DR and two-step change in DR were analyzed.
Results: There were 276 subjects in total, with a mean age of 59.8 ± 8.9 years. The majority were male (73%) and the mean glycated hemoglobin A1c (HbA1c) level and mean duration of diabetes were 7.7 ± 1.4% and 14.0 ± 10.5 years, respectively. After adjustments for age, sex, smoking, duration of diabetes, HbA1c, hypertension, and hyperlipidemia, the responses of retinal arterioles to flicker stimulation were lower in subjects with incident DR (P = 0.048). Subjects with greater arteriolar dilatory responses were less likely to have DR progression (odds ratio [OR] 1.85, [95% confidence interval [CI] 1.33-2.56], P = 0.012, per SD decrease). Subjects with greater venular dilatory responses were also less likely to have DR progression (OR 1.89, [95% CI 1.35-2.63], P = 0.003, per SD decrease). There were no significant associations between arteriolar or venular dilation response and incident proliferative DR (PDR) and DR regression.
Conclusions: Reduced retinal arteriolar and venular dilatory responses to flickering light are associated with risk of DR progression at 1 year in adult patients with diabetes.