Radial peripapillary capillary vessel density loss is associated with structural and visual field damage in patients with open-angle glaucoma

Abstract

Purpose : To investigate radial peripapillary capillary (RPC) vessel density (VD) in healthy subjects and open angle glaucoma (OAG) patients with different functional and structural disease severity.

Methods : 228 subjects (95 OAG; 133 healthy) were assessed in a cross-sectional analysis for RPC small vessel (SV) and all vessels (AV) VD via optical coherence tomography angiography (OCTA, Optovue). Patients were classified: for structural severity based on the OCTA-derived vertical cup/disc classification in 3 groups with increased structural damage: within normal limit (N), borderline (B); outside normal limit (O); for functional severity based on the Glaucoma Staging System 2 (GSS2) of Brusini in 3 groups with increased functional damage: Group 1 (Stage 0, no defect or minimal); 2 (border and Stage 1, early); 3 (Stage 2, moderate; Stage 3, advanced; Stage 4, very advanced). Nonparametric tests, with adjustment for patient characteristics, were used to test for differences with p<0.05 considered statistically significant.

Results : RPC VD parameters were statistically significantly higher in healthy subjects compared to glaucoma patients (all p<0.05). In OAG patients, the RPC VD parameters decreased as the structural damage increased, with statistically significant differences between groups, both for global SV VD (whole image: N=44.32 (4.60); B=43.76 (3.59); O=39.79 (3.84); N versus B p=0.014; N versus O p<0.001; B versus O p=0.040; peripapillary: N=46.55 (5.27); B=45.99 (3.22); O=40.87 (4.78); N versus B p=0.012; N versus O p<0.001; B versus O p=0.023) and for global AV (whole image AV: N=50.19 (4.42); B=49.95 (3.54); O=45.89 (3.84); N versus B p=0.045; N versus O p<0.001; B versus O p=0.039). VD parameters were also statistically significantly lower in OAG patients with increased functional disease severity (GSS2 group 3 compared to group 2), both for the global and superior and inferior hemispheres values of SV and AV (p=0.001-0.009).

Conclusions : Our study shows that progressive peripapillary vessel density dropout occurs with both increased structural and functional OAG disease severity. Well-powered longitudinal studies are needed to confirm the predictive role of retinal capillary loss and VD biomarkers for OAG progression.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.