Objectives: We compared long-term endothelial cell survival after penetrating versus after deep anterior lamellar keratoplasty for keratoconus.
Materials and methods: We retrospectively compared 64 eyes of 55 patients who had penetrating keratoplasty and 40 eyes of 37 patients who had deep anterior lamellar keratoplasty for keratoconus (October 2003-February 2021). Best-corrected visual acuity, Goldmann applanation tonometry, fundus examination with 90D lens, and specular microscopy with CEM-530 (Nidek) were performed preoperatively and every 6 months postoperatively. Main outcomes were endothelial cell density, central corneal thickness, and visual acuity. Secondary outcomes were coefficient of variation, hexagonality, graft rejection episodes, and graft clarity.
Results: We found no significant differences between the 2 treatment groups regarding patient age, donor age, preoperative vision, central corneal thickness, and recipient-donor trephine diameters. Mean follow-up was 92.5 months. In deep anterior lamellar keratoplasty, the endothelium was preserved significantly better for 10 years versus for penetrating keratoplasty. Mean endothelial density in penetrating versus deep anterior lamellar keratoplasty was 2006.7 versus 2354.7 cells/mm2 at 1 year (P = .010), 1170.5 versus 2048.2 at 5 years (P <.001), and 972.5 versus 1831.6 at 10 years (P < .001). Cumulative endothelial cell loss was 43% and 19.7% at 10 years for penetrating and anterior lamellar keratoplasty, respectively. Significantly more thickening of central cornea was shown in penetrating keratoplasty after 7 years. Corneal thickness was 583.0 µm in penetrating and 545.1 µm in deep anterior lamellar keratoplasty (P = .002) at 10 years. Vision gain and coefficient of variation were similar. Hexagonality decreased significantly in both groups at 10 years. Rates of rejection were 12.5% in penetrating and 7.5% in deep anterior lamellar keratoplasty. Graft survival rates were 97.5% and 96.9%, respectively.
Conclusions: In keratoconus, endothelial vitality is better preserved with deep anterior lamellar keratoplasty than with penetrating keratoplasty over a 10-year follow-up.