Correlation between foveal avascular zone size and foveal morphology in patients with idiopathic macular epiretinal membrane

Abstract

Objective To analyze the correlation between foveal avascular zone (FAZ) size and foveal morphology in patients with idiopathic macular epiretinal membrane (IMEM) using OCT angiography (OCTA). Methods A retrospective case series study contained of 54 eyes of 54 patients affected with IMEM (IEM group) and 50 eyes of 50 normal persons as the control group. The BCVA was measured using the international standard visual acuity chart, and the results were converted to the logMAR visual acuity. The FAZ areas were evaluated with OCTA in both the superficial and deep capillary plexus layers by using 3 mm×3 mm images of the macular. The central macular thickness (CMT), inner retinal layer thickness (IRT), outer retinal layer thickness (ORT), subfoveal choroidal thickness (SFCT), and the status of ellipsoid zone (EZ) were assessed with spectral-domain optical coherence tomography. The differences of FAZ areas between the two groups were analyzed. The correlative analysis was performed to investigate the relationship between areas and foveal morphology. Results Compared with control group, the FAZ area in superficial and deep capillary plexus in the IMEM group were significantly smaller (t=−29.095, −28.743; P<0.001, <0.001); the mean CMT, IRT, ORT and SFCT were significantly thickening in the IMEM group (Z=−8.784, −8.524, −7.709, −7.535; P<0.001,<0.001, <0.001, <0.001). In the IMEM group, the FAZ area in superficial capillary plexus correlated inversely with the CMT, IRT, and the integrity of EZ (r=−0.464, −0.536, −0.293; P<0.001, <0.001, 0.039), no significant correlation of superficial plexus FAZ areas with ORT and SFCT (r=−0.218, −0.165; P=0.172, 0.157). The FAZ area in deep capillary plexus correlated inversely with the CMT, IRT, and the integrity of EZ (r=−0.306, −0.694, −0.468; P=0.037, <0.001, <0.001), no significant correlation with ORT and SFCT (r=−0.242, −0.227; P=0.079, 0.094). Conclusions The FAZ areas is significantly decreased in IMEM eyes compared with normal eyes. Both superficial and deep FAZ area are correlated with the CMT, IRT, and the integrity of EZ. Key words: Macula lutea; Membranes; Tomography, optical coherence; Foveal avascular zone