Correlation between new OCT parameters and metamorphopsia in advanced stages of epiretinal membranes

Abstract Purpose To correlate metamorphopsia provided by M‐CHARTS and ectopic inner foveal layers (EIFL) or ‘central bouquet’ abnormality (CBA) in patients with advanced stages of epiretinal membrane (ERM) following the novel Optical Coherence Tomography (OCT)‐based grading scheme. Methods In 60 eyes of 57 patients affected by ERM (stages 3 and 4), the degree of metamorphopsia using the M‐CHARTS was evaluated (M‐SCORE) and correlated with EIFL, CBA and central foveal thickness (CFT) as measured on OCT scans. Results A total of 37 and 23 eyes were diagnosed having ERM stages 3 and 4, respectively. Mean vertical and horizontal M‐SCORE (M‐V and M‐H) were 0.64 ± 0.43 and 0.58 ± 0.37 standard deviations, respectively. Mean M‐SCORE exhibited a statistically significant correlation with EIFL and CFT (both p < 0.0001), but not with CBA (p = 0.84). Analysing the direction of metamorphopsia separately, M‐H and M‐V were significantly correlated with EIFL (both p < 0.0001), but not with CBA thickness (p = 0.70 and 0.33 respectively). Ectopic inner foveal layers (EIFL) was significantly influenced by the presence of CBA (CBA present, 158.29 ± 63.53 micron; CBA absent, 107.05 ± 94.13 micron, p = 0.04). No significant differences were found for both M‐V and M‐H with respect to the presence of CBA. Conclusions Based on the novel OCT‐based grading scheme for ERMs, our results demonstrate that EIFL, but not CBA, might be considered a good indicator for metamorphopsia in patients with advanced ERMs.