Comparative analysis of outcomes of surface ablation for myopic astigmatism in patients after PKP and DALK

Purpose To compare the outcomes of surface ablation (SA) in patients who have previously undergone Deep Anterior Lamellar Keratoplasty (DALK) and Penetrating keratoplasty (PKP). Methods This retrospective study evaluated the outcomes of SA in Keratoconus (KCN) patients who had previously undergone DALK or PKP and at least 6 months has passed after complete suture removal. Participants required a follow-up of at least four years. A total of 36 eyes (20 post-DALK, 16 post-PKP) were included. Collected data comprised demographics (age, gender, affected eye) and clinical characteristics (refractive error, corrected and uncorrected distance visual acuity [CDVA, UDVA], central corneal thickness, keratometry, surgical details, ablation depth, mitomycin duration, and complications). Primary outcomes included final refractive error, CDVA, and UDVA. Results Demographic and clinical characteristics were similar between groups. Comparing SA outcomes, no significant differences were found in safety index (1.14 vs. 1.12, P = 0.69), efficacy index (0.94 vs. 0.84, P = 0.27), logMAR CDVA (0.23 vs. 0.18, P = 0.34), logMAR UDVA (0.34 vs. 0.30, P = 0.52), or postoperative spherical equivalent (SEQ) (−2.18 vs. −1.36, P = 0.19). Complications and corneal haziness were minimal in both groups. However, SEQ showed notably greater stability over 48 months in the DALK group. Conclusion SA surgery after corneal transplantation effectively manages refractive errors with minimal complications. While outcomes were generally comparable, DALK patients exhibited greater long-term SEQ stability.