Effect of intraocular pressure lowering on the capillary density of optic nerve head and retinal nerve fiber layer in patients with glaucoma.

Abstract

To evaluate the effect of IOP lowering on the capillary density of optic nerve head and retinal nerve fiber layer in patients with primary open angle glaucoma. Twenty eyes of 14 glaucomatous patients and 15 eyes of nine normal patients were enrolled. The most appropriate hypotonic treatment was applied to every patient. A HD Angio Disc 4.5 scan (Avanti-AngioVue) was performed at baseline and after a month in the glaucomatous eyes. The following parameters were analyzed: Radial Papillary Capillaries (RPC) density, inside disc, peripapillary, superior-hemi, inferior-hemi, quadrants, and peripapillary, hemi-superior, hemi-inferior, and quadrants RNFL thickness. Optic nerve head analysis was also evaluated. In addition, the RPC density and the RNFL were assessed in the eight sectors provided by the software. The RPC density did not significantly change after IOP reduction (p > 0.05). The inferior-temporal (p = 0.005) and inferior-nasal sectors (p < 0.001) showed a greater capillary density than the respective superior sectors in healthy eyes. In contrast in the glaucomatous eyes, the superior-nasal exhibited greater capillary density with respect to the inferior-nasal sectors. The aggregate RPC density of the inferior sectors was greater than the superior ones in the control group (p < 0.001). An improvement of the average disc area (p = 0.01) and the average cup volume (p = 0.059) were also observed along with increased RNFL thickness at different locations (all, p < 0.05) after IOP lowering therapy was initiated. The glaucomatous eyes presented rarefaction of the radial papillary capillaries density in the inferior sectors, but no significant changes in the density after IOP-lowering medications.