deep anterior lamellar keratoplasty using frozen versus fresh corneas in patients with keratoconus

purpose: to compare the clinical and paraclinical outcomes following deep anterior lamellar keratoplasty (dalk) using frozen versus fresh corneas in patients with keratoconus. methods: in this prospective, comparative interventional study, 16 frozen and 19 fresh corneas were used during dalk in keratoconus patients. big bubble technique was used in all patients. the two groups were compared at 3 and 6 months after surgery in terms of best spectacle-corrected visual acuity (bscva), graft clarity, the rate of epithelial defect improvement, graft rejection and pachymetry. confocal scan was performed to measure and compare basal epithelial cell density, keratocyte density at anterior, middle and posterior stroma, interface haziness and endothelial cell density. results: the study included 22 female and 13 male subjects with mean age of 27±5 (21-32) years. there was no statistically significant difference between the two groups regarding mean value of bscva, central corneal thickness, basal epithelial cell density and endothelial cell density. graft epithelial defects improved by 7 days postoperatively in both groups. the rejection-free graft survival rate was 100% in both groups. three months postoperatively, two grafts belonging to the frozen cornea group were not clear. of which, one became clear after 6 months. there was a significant difference between anterior, middle and posterior keratocyte density with mean keratocyte density of zero at both 3 and 6 months postoperatively in the frozen corneas. confocal scan demonstrated significantly higher interface haziness after 3 months, in frozen corneas after 6 months (p<0.05). conclusion: dalk using frozen corneas seems to yield clinical and paraclinical results comparable to dalk using fresh corneas.