Paired-Eye Analysis of Deep Anterior Lamellar Keratoplasty Versus Mushroom Penetrating Keratoplasty Over 5 Years

Purpose: To evaluate and compare the clinical outcomes of keratoconic patients who received deep anterior lamellar keratoplasty (DALK) in one eye and mushroom penetrating keratoplasty (MK) in the fellow eye. Design: Retrospective interventional case series based on prospectively collected data. Subjects: Keratoconic patients who underwent keratoplasty at the department of ophthalmology of "Villa Igea," Ospedali Privati Forlì (Forlì, Italy) between July 2006 and December 2023. Intervention: Patients underwent DALK in one eye and converted MK from intended DALK in the fellow eye. Main outcome measures: The primary outcomes were best spectacle-corrected visual acuity (BSCVA), refractive astigmatism, and endothelial cell density (ECD). Kaplan-Meier curves were drawn for both DALK and MK to compare the cumulative probability of obtaining a BSCVA < 0.3 LogMAR (Snellen 20/40) within the end of follow-up. Results: We included 46 keratoconic patients that underwent DALK in one eye and MK in the fellow eye. Mean follow-up was 5.4 ± 2.1 years (up to 10 years). During the first two years after surgery, BSCVA was significantly better in the DALK group (0.08 ± 0.11 vs 0.15 ± 0.20 LogMAR, P = .05); however, no significant differences between the 2 groups were found at later follow-up times. At 5 years, BSCVA values were 0.08 ± 0.10 and 0.12 ± 0.18 LogMAR, respectively for DALK and MK (P = .305). The 5-year probability of retaining a BSCVA < 0.3 LogMAR was 85.1% and 83.0%, respectively for DALK and MK (P = .791). Three years postoperatively, refractive astigmatism was significantly lower for DALK (at 5 years, 2.37 ± 1.21 D vs 2.97 ± 1.13 D; P= .04); however, the percentage of eyes with astigmatism higher than 4.5 D did not significantly differ between DALK (n = 3) and MK (n = 2) (P > .99). Five years postoperatively, ECD was 1837 ± 625 cells/mm² for DALK and 1083 ± 378cells/mm² for MK (P < .001). At 1 year, mean ECL was 20.3% for DALK and 35.4% for MK (P = .008). Thereafter, mean annual ECL was 1.4% for DALK and 5.9% for MK (P = .021). Conclusion: This study allowed direct intra-patient comparison between DALK and MK. Compared with MK, our findings showed for DALK better BSCVA during the first 2 years after surgery, lower refractive astigmatism from 3 years postoperatively on, and higher ECD at all time points.