Association of foveal avascular zone with the metamorphopsia in epiretinal membrane

This study was to investigate the relationship between the metamorphopsia and foveal avascular zone (FAZ) parameter in eyes with epiratinal membrane (ERM). We studied patients with an ERM visited retinal service unit at the Kagoshima University Hospital or Shirai Hospital. The best-corrected visual acuity (BCVA), and the degree of metamorphopsia by M -CHARTS (TM) were evaluated. The 3x3 mm optical coherence tomography angiography (OCTA) images of the superficial layer were obtained. Area (mm(2)), the circularity, eigen value were calculated using ImageJ software. The relationship between visual function, such as best corrected visual acuity (BCVA) and metamorphopsia, and FAZ parameters were studied by Pearson's correlational coefficient. Fifty-four eyes of 51 patients (24 men and 27 women) with an ERM were studied. The mean age of the patients was 69.6 +/- 8.20 years. The mean BCVA and metamorphopsia score was 0.31 +/- 0.29 logMAR units and 0.49 +/- 0.42. There was no significant relationship between BCVA and FAZ parameters. While, metamorphopsia score was significantly and negatively correlated with all of FAZ parameters (area R=-0.491, P<0.001; circularity R=-0.385, P=0.004; eigenvalue ratio R=-0.341; P=0.012). Multiple regression analysis showed the FAZ area was solely and significantly correlated with metamorphopsia score (beta -0.479, P<0.001). The size but not the shape of the FAZ was significantly correlated with the degree of metamorphopsia suggesting that it could be an objective parameter of metamorphopsia in ERM patients.