Quantitative analysis on microvasculature in the optic disc area of patients with unilateral branch retinal vein occlusion

Abstract

AIM: To observe the changes of retinal nerve fiber layer(RNFL)thickness and radial peripheral capillary(RPC)density in patients with unilateral branch retinal vein occlusion(BRVO), and further analyze the correlation between RPC density and RNFL thickness.METHODS: Observational study. Totally 37 patients with unilateral BRVO diagnosed at the ophthalmology department of First Hospital of Qinhuangdao from October 2020 to January 2022 were selected, the 37 affected eyes were the unilateral BRVO group, and 37 fellow healthy eyes were the contralateral unaffected group, and 35 healthy individuals(35 right eyes were selected)without ocular diseases during the same period were selected as the normal control group. The best corrected visual acuity, intraocular pressure, anterior segment, fundus and optical coherence tomography angiography(OCTA)were examined in both eyes of all BRVO patients and healthy individuals. The central macular thickness(CMT), the RNFL thickness, and the optic disc-AV crossing distance(DAVD)were measured by built-in software of the OCTA equipment. The optimized U-net algorithm was used to eliminate the large blood vessels, and then the RPC density was calculated. The CMT, RNFL thickness and RPC density were compared among the three groups. And the correlations of the RPC density with the CMT, RNFL thickness, and the DAVD were investigated.RESULTS: Compared with the contralateral unaffected group and the normal control group, the CMT and the RNFL thickness were significantly thickened in the unilateral BRVO group(all P0.05). The RPC density in the unilateral BRVO group increased compared with the contralateral unaffected group and decreased compared with the normal control group, but there was no statistically difference(all P>0.05). However, the RPC density in the contralateral unaffected group decreased compared with the normal control group(P<0.05). The RPC density in the unilateral BRVO group was not correlated with the CMT(P=0.960), but positively correlated with the RNFL thickness(r=0.401, P=0.014)and negatively correlated with the DAVD(r=-0.339, P=0.040).CONCLUSION: The RNFL thickened significantly and the RPC density did not change significantly in the optic disc area of BRVO patients. The RPC density is positively correlated with the RNFL thickness, indicating that the RNFL thickness can be used as a monitoring indicator to analyze and study the damage degree of the RPC density.

Keywords

• branch retinal vein occlusion
• optical coherence tomography angiography
• radial peripheral capillary density
• retinal nerve fiber layer thickness
• optic disc-av crossing distance