Lower retinal capillary blood flow predicts structural glaucoma progression after 5 years

Abstract

Purpose: To examine the capillary blood flow parameters and structural progression in patients with open-angle glaucoma (OAG) over a 5-year period.

Methods: 112 OAG patients (Mean age 65 yr; 44 male) 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 (Mean age 70 yr; 16 male) 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 a 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.

Results: In OAG patients over a 5-year period of time, the number of Superior Zero Pixels significantly increased from 0.200 (95% CI; 0.189, 0.213) at baseline to 0.225 (95% CI; 0.202, 0.251) at 5 years with a change of 0.022 (0.002, 0.040; p=0.0334), the number of Inferior Zero Pixels significantly increased from 0.185 (95% CI; 0.174, 0.197) at baseline to 0.205 (95% CI; 0.186, 0.225) at 5 years with a change of 0.018 (0.001, 0.033; p=0.0418). Higher number of Superior Zero Pixels was significantly associated with shorter time to structural progression (p=0.0009).

Conclusions: The amount of retinal area with no capillary blood flow increased over a 5-year period while lower capillary blood flow predicted glaucomatous structural progression.