Baseline retinal capillary blood flow parameters predict structural glaucoma progression in diabetic patients with open-angle glaucoma

Abstract

Purpose: To examine the retinal capillary blood flow parameters and structural progression in patients with open-angle glaucoma (OAG) with and without diabetes mellitus (DM) over a 5-year period.

Methods: 112 OAG patients (Mean age 65 yr; 21 with DM, 91 without DM) were assessed for retinal capillary blood flow as measured by Heidelberg retinal flowmetry at baseline and every 6 months for a 5-year period. 30 patients (6 with DM, 24 without DM) were assessed at 5-year follow-up. Disease progression was monitored with optical coherence tomography and Heidelberg retinal tomography and defined as two consecutive visits with Retinal Nerve Fiber Layer thickness decrease ≥8% and/or horizontal or vertical cup/disk ratio increase ≥0.2 compared to baseline. Mixed-model ANCOVA was used to test for significant change from baseline to 5-year follow-up. Time to structural progression was analyzed using Cox proportional hazards models. Interactions were tested to determine if the effects of the factors on progression time differed by diabetes.

Results: The number of superior zero pixels was 0.200 (95% CI; 0.179, 0.224) at baseline in patients with DM and 0.196 (95% CI, 0.184, 0.208) in patients without DM. Higher number of superior zero pixels at baseline was significantly associated with shorter time to structural progression in patients with DM (p=0.0297, hazard ratio 1.46 with 95% CI 1.04 to 2.05 for 0.1 difference in number of superior zero pixels) but not in patients without DM (p=0.5924, hazard ratio 1.0), leading to a significant difference between groups (p=0.0352).

Conclusions: In this group of patients higher amount of retinal avascular area at baseline was predictive of glaucomatous structural progression in patients with DM but not in patients without DM. These findings suggest that capillary blood flow may play a different role in the structural progression of the disease in patients with DM compared to patients without DM.