['To assess the impact of duration of topical steroid treatment on the incidence of endothelial graft rejection after normal-risk penetrating keratoplasty (PK).', 'Prospective, institutional, longitudinal, randomized interventional trial including 406 eyes (age 52 +/- 19 years; follow-up 42 +/- 18 months).', 'Postoperative treatment started with prednisolone acetate 1% eye drops five times daily and was tapered over the first six months. Patients were then randomized into either short-term (stop topical steroid treatment) or long-term treatment (continue steroids once daily for 12 months).', 'During follow-up, 29 eyes (7.1%) developed an episode of endothelial graft rejection. Graft rejections were significantly more common in the short-term (19 of 202; 9.1%) compared with the long-term treatment group (10 of 204: 4.9%; P = .001).'] Does long-term topical steroid treatment improve graft survival following normal-risk penetrating keratoplasty?