Peripapillary capillary vessel density in normal tension glaucoma and primary open-angle glaucoma

Abstract

Introduction/Objective Primary open angle glaucoma (POAG) is а chronic, progressive, optic neuropathy with possible blindness and irreversible changes in the optic nerve head (ONH). Optical coherence tomography (OCT) is non-invasive method that provides structural glaucoma damage evaluation. OCT angiography (OCTA) provides qualitative and quantitative assessment of peripapillary microvasculature. The objective of this study was to determine whether there is a difference in peripapillary capillary vessel density (VCD) in normal tension glaucoma (NTG), POAG and healthy subjects.

Methods This prospective study included 120 eyes: 40 healthy eyes, 30 eyes with NTG and 50 eyes with POAG. Ophthalmological examination, central corneal thickness, OCT, OCTA also visual field were performed.

Results Vessel capillary density total (VCD total) is significantly higher in healthy compared to NTG and POAG (39.25 ± 0.94 vs. 36.79 ± 2.50 vs. 37.58 ± 1.53; p < 0.001). Peripapillary VCD (VCD perip.) is lower significantly in NTG and POAG in comparison with healthy subjects (39.21 ± 2.62 vs. 40.18 ± 1.35 vs. 41.29 ± 0.81; p < 0.001). VCD total is significantly lower in NTG compared to POAG (36.79 ± 2.50 vs. 37.58 ± 1.55; p < 0.001). We found significantly positive correlation between OCT and OCTA parameters of ONH with mean deviation (MD) index in NTG between retinal nerve fiber layer average with MD (r = 0.370, p < 0.05) also between VCD perip. inf. with MD (r = 0.395, p < 0.05). In POAG, we obtained a significantly positive correlation between VCD inf. with MD (r = 0.277, p < 0.05) also VCD inside disc with MD (r = 0.395, p < 0.01).

Conclusion Glaucoma patients have a significantly lower vessel density ONH and VCD perip. compared to healthy subjects. VCD total of ONH is significantly lower in NTG compared to POAG. We obtained a positive correlation between OCT and OCTA parameters with MD in NTG and POAG.

Keywords: optical coherence tomography angiography; optic nerve head; intraocular pressure