Influence of graft size on graft survival following Descemet stripping automated endothelial keratoplasty

PURPOSE: To evaluate graft size on outcome following Descemet stripping automated endothelial keratoplasty (DSAEK) METHODS: Consecutive patients who had undergone a DSAEK for Fuchs endothelial dystrophy (FED) and pseudophakic bullous keratopathy (PBK) with at least 1 year of follow-up. Patients were divided into three groups according to the size of the donor trephine: <9, 9 and 9.5 mm. Main outcomes were postoperative best corrected visual acuity (BCVA) and graft failure. Grafts were prepared using an automated microkeratome. For larger grafts (≥9 mm), a manual dissection of the residual peripheral ring of anterior lamella was performed before trephination. Donor age, endothelial cell density (ECD) and postmortem times; recipient details including risk factors, comorbidity, surgical complications and postoperative BCVA and graft survival were analysed. RESULTS: Of 174 patients, 131 were included: 84 (64%) with FED and 47 (36%) with PBK. Mean preoperative and postoperative BCVA were 1.01±0.76 and 0.2±0.2 logMAR, respectively, at 12 months with 80.5% achieving 20/40 or better. Postoperative BCVA was significantly associated with ECD (p=0.005), PBK or FED (p=0.004), risk factors (p=0.007) and comorbidity (p=0.016). Eleven patients (8.40%) experienced endothelial graft failure; 17.86% for <9 mm, 7.69% for 9 mm and 3.84% for 9.5 mm trephine sized grafts. Graft failure was significantly associated with ECD (p=0.039) and graft trephine size (p=0.04). CONCLUSIONS: Larger grafts occupy a smaller chord length in the eye than the trephine size and are expected to provide 10%-20% more endothelial cells. Increased graft size and donor ECD is significantly associated with a reduced graft failure rate.