Change of Retinal Vessel Density After Lowering Intraocular Pressure in Ocular Hypertension.

Xuhao Chen,Qianru Wu,Chun Zhang,Ying Hong,Di Zhang,Haohao Di

doi:10.3389/fmed.2021.730327

Abstract

Purpose: To investigate the relationship between retinal microvasculature changes and intraocular pressure (IOP) for ocular hypertension (OHT) patients and further assess the factors associated with retinal microcirculation changes.Methods: This was a single-center prospective study designed for OHT patients, which consisted of two visits. After collecting baseline data of those who met the eligibility criteria, these patients were treated with latanoprost 0.005% ophthalmic solution for 4 weeks. Peripapillary vessel density (VD) of radial peripapillary capillaries (RPC) layer, macular VD in both superficial and deep layers, and foveal avascular zone (FAZ) area were measured by optical coherence tomography angiography (OCTA) before and after the treatment. We compared the changes in IOP and VD among the two visits by paired-sample t-test. Bonferroni correction was applied. Factors associated with VD changes were analyzed by linear regression analysis.Results: Thirty-four eyes of thirty-four patients were included. The mean IOP decreased by 6.5 ± 2.2 mmHg (p < 0.001). The peripapillary RPC VD increased significantly from 51.8 ± 2.5 to 53.0 ± 3.1% (Adjusted-p = 0.012). We found no significant difference in detailed sectors of the peripapillary region after correction. In the macular area, both the superficial and deep layers in foveal (superficial: 0.2 ± 1.9%, p = 0.523; deep: 0.0 ± 2.3%, p = 0.969) and parafoveal (superficial: 0.3 ± 3.0%, p = 0.565; deep: 0.5 ± 3.1%, p = 0.423) VD remained unchanged. The decrease of the mean FAZ area was insignificant (p = 0.295). The percentage of IOP reduction (β = 0.330, p = 0.031) and the baseline RNFL thickness (β = 0.450, p = 0.004) significantly correlated with the percentage of peripapillary RPC VD improvement in the multivariate linear regression analysis.Conclusion: The peripapillary VD in OHT patients increased after the reduction of IOP. The mild change of IOP did not alter the microcirculation in the macula. In addition, the percentage of IOP change and the baseline RNFL thickness were independent factors for the peripapillary RPC VD improvement.

Highlights

Intraocular pressure (IOP) and retinal circulation were influenced by autoregulation in normal tissue [1, 2]
A total of 34 eyes of 34 patients were included in the final analysis
As we found a significant increase in peripapillary radial peripapillary capillaries (RPC) VD, we further explored its association with different parameters using linear regression analysis

Summary

Introduction

Intraocular pressure (IOP) and retinal circulation were influenced by autoregulation in normal tissue [1, 2]. Based on the models’ nature, the long-term effect of IOP change on retinal circulation remained unsolved. Given the damaging retinal circulation with glaucoma progression [19], the correlation between the extent of microcirculation improvement and IOP reduction was inconsistent among studies. Ocular hypertension (OHT) patients present no signs of glaucomatous defects but suffer the risk of developing and progressing into primary open-angle glaucoma (POAG) with long-term IOP elevation [20,21,22]. Previous studies revealed that the IOP reduction for OHT showed little impact on the ophthalmic artery [23]. The peripapillary and macular microcirculation and their associations with IOP change for OHT were not thoroughly evaluated, which may affect the robustness to its therapeutic value. The factors associated with microcirculation changes still need to be explored

Methods

Results

Conclusion