Risk factors for postoperative intraretinal cystoid changes after peeling of idiopathic epiretinal membranes among patients randomized for balanced salt solution and air-tamponade

PURPOSE: Epiretinal membranes (ERM) are macular disorders leading to loss of vision and metamorphopsia. Vitrectomy with membrane peeling displays the gold standard of care. Aim of this study was to assess risk factors for postoperative intraretinal cystoid changes in a study population randomized for balanced salt solution and air-tamponade at the end of surgery. METHODS: A prospective randomized study, including 69 eyes with idiopathic ERM. Standard 23-gauge three-port pars plana vitrectomy with membrane peeling, using intraoperative optical coherence tomography (OCT), was performed. Randomization for BSS and air-tamponade was performed prior to surgery. RESULTS: Best-corrected visual acuity improved from 32.9 letters to 45.1 letters 3 months after surgery. Presence of preoperative intraretinal cystoid changes was found to be the only risk factor for presence of postoperative intraretinal cystoid changes 3 months after surgery (p = 0.01; odds ratio: 8.0). Other possible risk factors such as combined phacoemulsification with 23G-ppv and membrane peeling (p = 0.16; odds ratio: 2.4), intraoperative subfoveal hyporeflective zones (p = 0.23; odds ratio: 2.6), age over 70 years (p = 0.29; odds ratio: 0.5) and air-tamponade (p = 0.59; odds ratio: 1.5) were not found to be significant. CONCLUSION: There is strong evidence that preoperative intraretinal cystoid changes lead to smaller benefit from surgery.