Background. The aim of this study was identification of predictive factors for postoperative visual acuity in patients with a clear organ-cultured graft and to analyze the change in visual acuity between 12 and 24 months after transplantation. Methods. The study design was a prospective cohort study. A total of 342 consecutive penetrating keratoplasties using donor organ-cultured grafts, performed in 324 patients, were included. Visual acuity, graft thickness, and graft endothelial cell density were recorded in patients with clear transplants. Results. At 24 months postoperatively, 25 (18.7%) of 134 patients had 20/200 or worse visual acuity and 66 (49.3%) had 20/40 or better visual acuity, Graft thickness book 1 month to decrease to normal values. A temporary graft thinning occurred at 6 months postoperatively, followed by recovery of normal graft thickness by 18 months. The average postoperative endothelial cell density was 1,533+/-598 cells/mm(2) during the second year. The 24-month LogMAR (logarithm of minimal angle of resolution) visual acuity correlated with preoperative LogMAR visual acuity (beta=0.26, P=0.005), postoperative lens status (beta=-0.34, P=0.009), preoperative intraocular pressure (beta=0.50, P=0.020), and postoperative astigmatism (beta=0.17, P=0.040), Visual acuity (P=0.022) significantly improved between 1:1 and 24 months. Preoperative diagnosis (P < 0.0001) and postoperative lens status (P < 0.0001) significant:ly influenced the change in LogMAR visual acuity between 12 and 24 months. Conclusions. Donor variables do not influence the visual acuity results of penetrating keratoplasty using organ-cultured donor tissue, whereas they have a strong influence on graft survival and graft endothelial cell density. Visual acuity improves during the first 2 years after transplantation. After keratoplasty, organ-cultured corneal grafts undergo dramatic modifications of their thickness and probably of their transparency.