Association of Vessel Density, Perfusion and Flux Index with Glaucoma Severity Assessed by OCT Angiography.

Abstract

Purpose : Optical coherence tomography angiography (OCTA) is a noninvasive imaging technique that provides a quantitative assessment of the microcirculation of the retina and choroid. OCTA might allow us to expand our understanding on the pathophysiology of glaucoma and its clinical outcomes. The aim of this study is to investigate the association of vessel density, perfusion and flux index in the peripapillary/macular regions with different structural and functional variables at different stages of the disease

Methods : A cross-sectional retrospective study of consecutive cases which underwent a battery of ancillary tests to assess glaucoma patients was performed. A total of 135 eyes from 65 patients (glaucoma suspects and glaucoma patients) were included. Complete medical records and good quality results from a battery of tests were analyzed, including peripapillary and macular OCTA (Cirrus 6000, Carl Zeiss). Multiple functional and structural variables were assessed in different stages of glaucoma. A P-value of ≤ 0.05 was considered as statistically significant.

Results : Patients had a mean age of 63.35±13.44 years. The sample had a greater proportion of female (66.1%), primary open-angle glaucoma (53.8%), and early stages of the disease (63.07%). The mean thickness values of retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) demonstrated a good correlation (r≥0.5). All of the mean values of peripapillary perfusion and flux index were statistically significance in each eye (P=0.0001), with exception of flux index in the left eye, in which the correlation was modest (r>0.36) but maintaining a level of statistical significance (P≤0.002). A statistically significant (P<0.005) but modest correlation (r≥0.34) was found between CFNR and GCC as well as the variables, macular perfusion and macular vessel density. When the mean values of peripapillary perfusion and flux index where compared between two subgroups of severity (mild glaucoma vs. glaucoma suspect), statistically significant differences were found in both eyes (table 1).

Conclusions : In our study, peripapillary perfusion and flux index are variables derived from OCTA assessment that correlates well with important structural elements at different stages of glaucoma. Well-designed studies could determine the diagnosis and prognosis capacities of such technology in order to improve therapeutic decisions.

This is a 2021 ARVO Annual Meeting abstract.