[Retinal vessel density in primary open-angle glaucoma with a hemifield defect].

Abstract

Objective: To evaluate the retinal vessel density in eyes with primary open-angle glaucoma (POAG) with single-hemifield visual field (VF) defects and its relationship to retinal nerve fiber layer (RNFL) thickness and visual field indices. Methods: Cross-sectional study. Twenty-eight POAG patients with single-hemifield VF defects and 31 normal controls were recruited from October 2015 to October 2018 in the Eye, Ear, Nose and Throat Hospital of Fudan University. All subjects underwent complete ophthalmological examinations, including RNFL, retinal ganglion cell complex (GCC) thickness and visual field tests, and the general information was collected. The peripapillary radial peripapillary capillaries (RPC) and macular superifical retinal capillary plexus (SCP) were derived from optical coherence tomography angiography. The retinal vessel density, structural values, and VF values were compared among the corresponding hemifields of POAG and healthy eyes using the Rank Sum test. Results: There were 16 males and 12 females in POAG patients, with the age of (47±12) years; there were no significant differences in gender distribution, age, intraocular pressure, central corneal thickness, axial length and intraocular perfusion pressure between POAG patients and the normal controls (all P>0.05). Among POAG patients, there were 19 cases with upper and 9 cases with lower visual field defect. In the POAG eyes, the vascular density of peripapillary RPC and macular SCP were 45.86% (34.92%-52.78%) and 39.31% (32.55%-46.79%), respectively. In the normal eyes, the vascular density of peripapillary RPC and macular SCP were 56.90% (51.69%-60.84%) and 47.48% (37.95%-52.25%), respectively. The difference was statistically significant (Z=-6.56, -5.86; both P<0.01). The RNFL and GCC thicknesses in the POAG group were 84.4 (62.1-97.1), 76.4 (60.3-92.5) μ m, respectively, which were smaller than those in normal controls [110.6 (95.7-131.6), 98.1 (84.0-109.2) μm; Z=-6.57, -6.36; both P<0.01]. In the POAG eyes, the peripapillary RPC [44.12% (34.73%-53.20%) vs. 51.85% (38.64%-61.02%); Z=-4.62; P<0.01] and macular SCP [36.81% (29.73%-47.82%) vs. 41.78% (33.93%-49.22%); Z=-4.12; P<0.01] vessel densities were reduced in the abnormal hemisphere compared with the opposite hemisphere. Compared with the normal eyes, the normal hemisphere of the POAG eyes had lower peripapillary RPC and macular SCP vessel densities (Z=-5.08, -4.95; both P<0.01), a thinner RNFL and a thinner retinal GCC [93.0 (61.9-116.5) μm vs. 110.6 (95.7-131.6) μm, Z=-5.15; 86.3 (67.2-98.2) μm vs. 98.1 (84.0-109.2) μm, Z=-5.35; both P<0.01]. But the mean deviation and pattern standard deviation values of the VF were not significantly different between them (both P>0.05). Conclusions: The retinal vessel density reduce in eyes with POAG with single-hemifield VF defects. The normal hemisphere of POAG eyes have a reduced retinal microcirculation along with the thinning of the RNFL and GCC, suggesting that vascular dysfunction and structural changes preceded VF loss in POAG. (Chin J Ophthalmol, 2021, 57: 201-206).