Outcomes of cataract surgery in patients with previous corneal transplantation for keratoconus: comparison of PK and DALK.

Abstract

Purpose: To evaluate the visual and refractive outcomes of cataract surgery in patients with previous deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PK) performed for keratoconus.

Methods: This cross-sectional study evaluated patients with a history of corneal transplantation who underwent cataract surgery. Corrected distance visual acuity (CDVA) and manifest refraction were assessed postoperatively. Pre- and postoperative outcomes were compared using paired t-tests and Wilcoxon signed-rank tests, while intergroup (PK vs. DALK) differences were analyzed using independent t-tests and Mann-Whitney U tests. Finally, multivariable linear regression analysis was performed to adjust for potential confounding variables.

Results: A total of 24 eyes from 24 keratoconus-affected patients were included, comprising 12 patients in each of the DALK and PK groups. Following cataract surgery, CDVA, spherical refractive error, and spherical equivalent (SE) showed significant improvement (p = 0.023, < 0.001, and < 0.001, respectively), while cylindrical refractive error remained unchanged (p = 0.943). Patients in the DALK group demonstrated better CDVA compared to those in the PK group (p = 0.028), a difference that remained significant after adjusting for confounders (p = 0.004). However, refractive outcomes, including spherical refractive error, cylindrical refractive error, and SE did not differ between the two groups (p = 0.127, 0.247 and 0.347, respectively). Graft survival was excellent in both groups at final follow-up.

Conclusion: Although the sample size is small, the results of this study show that cataract surgery yields favorable visual and refractive outcomes in post-keratoplasty patients, with superior results observed in DALK cases compared to PK.