Changes in Ganglion Cell–Inner Plexiform Layer Thickness and Retinal Microvasculature in Hypertension: An Optical Coherence Tomography Angiography Study

Abstract

To investigate retinal blood flow in patients with hypertension using optical coherence tomography angiography (OCTA) and the relationship between blood flow metrics and ganglion cell-inner plexiform layer (GC-IPL) thickness. Retrospective, cross-sectional study. A total of 201 eyes from 117 healthy subjects and 84 hypertensive patients without any ocular abnormalities were included. Hypertensive patients were divided into the 2 groups according to disease periods (<5 years: Hypertension Group 1; ≥5 years: Hypertension Group 2). Macular 3× 3-mm angiography was acquired using the Zeiss Cirrus 5000 OCT instrument. Vessel density (VD), perfusion density (PD), and foveal avascular zone metrics of the superficial capillary plexus were automatically calculated, and the thicknesses of the central fovea, GC-IPL, and peripapillary retinal nerve fiber layer (RNFL) were measured. All measurements were compared among the 3 groups, and retinal blood flow metrics were correlated with the thickness of each retinal layer. Logistic regression analyses were performed to determine the factors associated with prolonged hypertension. The average GC-IPL (P < .001) and peripapillary RNFL (P= .048) thicknesses in Hypertension Group 2 were significantly thinner compared to the control group. The 3mm total area of the VD and PD was also decreased compared to the control group and Hypertension Group 1 (all P < .05), and was significantly correlated with the GC-IPL (VD: r= 0.450, P=.001; PD: r= 0.467, P < .001) and peripapillary RNFL (VD: r= 0.314, P= .027; PD: r= 0.328, P=.023) thicknesses in Hypertension Group 2. Using multivariate logistic analyses, only the average GC-IPL thickness was a significant factor for prolonged hypertension (odds ratio= 0.911, P= .002). In patients with hypertension lasting more than 5 years, inner retinal layer thinning, particularly GC-IPL thinning, was observed, which was significantly correlated with a decrease in retinal blood flow. Therefore, physicians should consider the effects of hypertension on the GC-IPL.