Penetrating and Deep Anterior Lamellar Keratoplasty for Keratoconus: A Comparison of Graft Outcomes in the United Kingdom

Abstract

Purpose. To compare outcomes after penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) for keratoconus in the United Kingdom. Methods. Patient outcome data were collected at the time of transplantation and at 1, 2, and 5 years after surgery. Data were analyzed by Kaplan-Meier survival curves, Cox regression, and binary logistic regression to determine the influence of surgical procedure on graft survival and visual outcome. Results. The risk of graft failure for DALK was almost twice that for PK (P = 0.02). Nineteen percent of the DALK failures occurred in the first 30 postoperative days compared with only 2% of PK failures. When these early failures were excluded, there was little difference between the 3-year graft survivals for DALK (92%; 95% confidence interval [CI], 85%–95%) and PK (94%; 95% CI, 92%–95%) (P = 0.8). Although the mean best corrected visual acuity (BCVA) was similar for the two procedures (P = 0.7), 33% of patients who underwent PK achieved a BCVA of 6/6 or better at 2 years compared with only 22% of those who underwent DALK (P < 0.001). Those with DALK were also likely to be more myopic (< −3 D) but there was little difference in scalar cylinder. Conclusions. DALK had a higher overall failure rate than PK. The difference was largely accounted for by early failures, which appeared to be related to the surgeon's experience. DALK recipients were less likely to achieve BCVA of 6/6 than were PK recipients and were more likely to have −3 D or worse myopia.