Non-supine versus supine position after endothelial keratoplasty: A systematic review and meta-analysis

There are some disputes regarding the necessity of maintaining a supine position after endothelial keratoplasty (EK) to ensure graft attachment. We aimed to evaluate the efficacy of a supine position after EK in reducing the risk of postoperative graft detachment. This systematic review with meta-analysis was registered in PROSPERO under protocol CRD42024541226. PubMed, Scopus, Embase, and Cochrane Central Register of Controlled Trials databases were systematically searched for studies comparing non-supine versus supine positions after EK. We pooled risk ratios (RR) and 95% confidence intervals (CI) for dichotomous outcomes and mean differences (MD) with 95% CI for continuous outcomes using a random-effects model. We included two randomized controlled trials and two observational studies comprising 456 eyes, of which 173 (37.9%) were assigned to non-supine positions. There were no significant differences in the incidence of graft detachment (RR 1.09; 95% CI 0.52-2.26; p = 0.82), rebubbling rate (RR 1.05; 95% CI 0.46-2.41; p = 0.90) and need for repeat keratoplasty (RR 2.37; 95% CI 0.13-41.99; p = 0.56) between non-supine and supine groups. There was also no difference in visual acuity (MD -0.02 LogMAR; 95% CI -0.11-0.08; p = 0.75) and intraocular pressure (MD -1.44 mmHg; 95% CI -8.49-5.61; p = 0.69) between groups. Subgroup analysis of DMEK (RR 0.73; 95% CI 0.38-1.42; p = 0.35) and DSAEK (RR 1.96; 95% CI 0.95-4.04; p = 0.07) also showed no difference in graft detachment between groups. Maintaining a supine position after EK surgery did not significantly affect graft detachment, rebubbling rate, need for repeat keratoplasty, visual acuity, or intraocular pressure.