Abstract:

Objective To evaluate the relationship between visual acuity and macular subregion morphology changes in the treatment of idiopathic macular epiretinal membrane (IMEM) via 23G vitrectomy combined with macular membrane dissection. Design Retrospective case series. Participants 78 cases (82 eyes) with IMEM which were treated via 23G vitrectomy combined with macular membrane dissection in Renmin Hospital of Wuhan University from 2015 to 2017. Methods According to the macular morphology of OCT before the operation, all patients can be categorized into four types, namely, normal group (24 eyes), diffuse edema group (39 eyes), cystoid macular edema group (9 eyes); the macular hole group (10 eyes). Record and analyze the preoperative clinical characteristics, surgical approaches, postoperative outcomes and postoperative complications at 7 days and 1 month after the operation. Main Outcome Measures The best corrected visual acuity (BCVA), fovea thickness, parafovea thickness and perifovea thickness before or after the operation. Results At the 7th days after vitrectomy, the BCVA was increased from 0.26±0.16 before operation to 0.36±0.16 (P=0.000); foveal thickness decreased from (506.41±112.67) μm to (442.39±82.10) μm (P=0.000); parafovea thickness recovered from (453.66±79.36) μm before operation to (409. 95±61.63) μm (P=0.000); perifovea thickness decreased from (365.93±50.84) μm to (356.76±54.20) μm (P=0.092); the BCVAs were all improved in the four groups (all P<0.05), and the improvement of visual acuity in the normal group was best (F=3.118, P=0.031). Compared with at the 7 days after the operation, the macular thickness decreased at one month after the operation, but the change of BCVA was not significant. Postoperative BCVA was correlated positively with preoperative BCVA (r=0.850，P=0.000), preoperative fovea thickness (r=0.7386，P=0.000), parafovea thickness (r=0.811，P=0.000), and perifovea thickness (r=0.799，P=0.000); and was correlated with postoperative fovea thickness (r＝-0.335，P＝0.035), parafovea thickness (r＝-0.376，P＝0.017), was not correlated with postoperative perifovea thickness (r=-0.310, P=0.052). Conclusion The removal of macular epiretinal membrane can significantly improve the visual function of patients and can also relieve the traction in the macular area and recover the structure of the macular region. The prognosis of visual acuity could be dicided at 1 weeks after operation, and the prognosis of visual acuity is best in patients with normal macular structure before operation.

Key words: idiopathic macular epiretinal membrane, best corrected visual acuity, fovea thickness, parafovea thickness, perifovea thickness