Relationship between abnormalities of retinal structures and vascular structures determined by optical coherence tomography angiography in eyes with branch retinal vein occlusion

Abstract

Purpose : To determine whether the size of the foveal avascular zone (FAZ) is significantly correlated with the best-corrected visual acuity (BCVA) and to examine the relationship between the size and microstructural changes of the photoreceptors in eyes with a branch retinal vein occlusion (BRVO).

Methods : This was a cross-sectional, retrospective study. The medical records of 69 eyes of patients (mean age, 64.6±11.7 years) with a BRVO who had undergone treatment with successful resolution of macular edema associated with a BRVO, and all were followed for at least 6 months. All the patients underwent optical coherence tomography (OCT) angiography (Angioplex) for measurement of the FAZ area and spectral-domain OCT for determination of microstructural changes of the photoreceptors at the fovea.

Results : The superficial and deep FAZ areas in eyes with a BRVO were 0.39±0.36 and 0.63±0.18 mm², and both were significantly larger than that in the fellow eyes (both, P<0.001). The mean pre-treatment BCVA was 0.49±0.47 LogMAR and the mean pre-treatment central foveal thickness (CFT) was 538.9±255.2 µm in the eyes with a BRVO. The mean post-treatment BCVA was improved to 0.30±0.36 LogMAR. The superficial FAZ area correlated with the post-treatment BCVA (r=0.285, P=0.027) but not with any parameters regarding the microstructures of the photoreceptors. The mean external limiting membrane (ELM)-ellipsoid zone (EZ) thickness was 39.7±12.6 µm and the mean EZ-RPE thickness was 30.5±12.7 µm in the eyes with a BRVO; both were significantly thinner than that in the fellow eyes (P<0.002, P<0.001). Univariate regression analysis showed that the post-treatment BCVA was significantly correlated with the pre-treatment BCVA (r=0.763, P<0.001); pre-treatment CFT (r=0.414, P=0.001); integrity of the ELM (r=-0.707, P<0.001), EZ (r=-0.587, P<0.001); ELM-EZ (r=-0.536, P<0.001) and EZ-RPE thicknesses (r=-0.548, P<0.001). Multivariate regression analysis showed that the pre-treatment BCVA (β=0.519, P<0.001) and integrity of the ELM (β=−0.373, P=0.001) were independent factors that significantly correlated with the post-treatment BCVA.

Conclusions : There was no significant correlation between the FAZ area and microstructural parameters. However, the integrity of the ELM was significantly correlated with the post-treatment BCVA in eyes with a BRVO.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.