Secondary epiretinal membrane after Ex-Press glaucoma filtration device implant

PURPOSE: To estimate the frequency of epiretinal membrane (ERM) in eyes with primary open-angle glaucoma (POAG) treated with Ex-Press shunt implant. Secondarily, we aimed to assess the role of concomitant cataract surgery and the impact of the ERM on central foveal thickness and macular volume. METHODS: In this prospective, consecutive, case-control study, we enrolled 54 patients affected by PAOG and scheduled for Ex-Press device implant with or without contemporary phacoemulsification. Contralateral eyes affected by POAG and receiving anti-glaucomatous eyedrops constituted the control group. Complete ophthalmologic evaluation and spectral-domain optical coherence tomography (OCT) were performed before and 1, 3 and 6 months after surgery. RESULTS: Twenty-six eyes received the Ex-Press implant alone, and 28 eyes underwent the combined procedure. Six months postoperatively, we observed 18 (33%) cases of ERM: 15 (28%) of cellophane macular reflex (CMR) and 3 (6%) of pre-macular fibrosis (PMF). In the control group, 9 (17%) eyes developed an ERM: 8 (15%) were CMR, and 1 (2%) was PMF. The frequency of ERM statistically differs between treated and contralateral eyes (P = 0.032, χ(2) test). The ERM frequency did not statically differ between eyes subjected to simple or combined surgery (P = 0.846, χ(2) test). Mean central foveal thickness and mean macular volume did not significantly differ between groups. CONCLUSION: The Ex-Press glaucoma shunt may increase the risk of ERM onset regardless of the concomitant cataract surgery; however, most cases were cellophane macular reflex with limited functional and anatomical impact. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00417-020-05025-8.