The foveal shape is not predictive of visual acuity and treatment response in macular edema due to retinal vein occlusion

Abstract

 

Purpose

 

The fovea as the functional center of the retina is a key structure when investigating visual function in retinal disease. It is common clinical belief that an abnormal shape of the fovea (such as eversion by macular edema) is a sign of poorer visual acuity and treatment outcomes; however, systematic investigations are lacking. The aim of this study was to characterize the foveal shape and to investigate corresponding functional and anatomical response patterns in patients with branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO).

 

Methods

 

Patients with CRVO or BRVO enrolled in phase III randomized multicenter trials with data available at the Vienna Reading Center were included. All patients were treated with ranibizumab injections. Baseline spectral-domain optical coherence tomography (OCT) scans of the study eye were processed using an automated image analysis pipeline consisting of denoising, motion correction, layer segmentation and foveal shape classification. Each scan was automatically assigned one of three foveal shape categories: 1) normal foveal depression, 2) minor foveal depression and 3) absent foveal depression. Best-corrected visual acuity (BCVA) at baseline, change in BCVA from baseline to month six, number of treatments, retinal thickness at baseline, and the change in thickness from baseline to six months were compared between these groups.

 

Results

 

72 eyes with CRVO and 56 eyes with BRVO were analyzed. In BRVO, 22 eyes (39%) presented a normal foveal depression, 7 (13%) a minor foveal depression, and 27 (48%) an absent foveal depression. In CRVO, 17 eyes (24%) showed a normal foveal depression, 16 (22%) a minor foveal depression and 39 (54%) an absent foveal depression. The comparison of anatomical and functional characteristics and treatment outcomes are presented in Table 1. There was a statistically significant difference in mean retinal thickness at baseline and change in retinal thickness, with thinner retinas in the normal foveal depression group and larger changes in the other groups. All other variables showed no statistically significant differences between the different foveal shapes.

 

Conclusions

 

Contrary to common clinical belief, baseline BCVA, change in BVCA and number of treatments seem independent of the foveal shape in macular edema due to retinal vein occlusion.  

 

Table 1