A Randomized Controlled Trial Comparing Femtosecond-Enabled Deep Anterior Lamellar Keratoplasty and Standard Deep Anterior Lamellar Keratoplasty (FEDS Study)

Abstract

Abstract Objectives To compare outcomes of femtosecond-enabled deep anterior lamellar keratoplasty (FE-DALK) and standard deep anterior lamellar keratoplasty (S-DALK). Methods An open-label, randomized controlled trial (Kensington Eye Institute, Toronto, Ontario, Canada) including 100 eyes of 97 participants with either keratoconus or corneal scarring, randomized to either FE-DALK (n = 48) or S-DALK (n = 49). Primary outcomes: postoperative astigmatism and surgically induced corneal astigmatism (SIA) – both at 15 months. Secondary outcomes: 6-, 12- and 15-month postoperative uncorrected- and best spectacle-corrected visual acuity, steep and flat keratometry, manifest sphere and astigmatism, rate of conversion to penetrating keratoplasty (PK), big-bubble success, central corneal thickness, endothelial cell count and complications. Results In intention-to-treat analysis, mean postoperative astigmatism in the FE-DALK (n = 30) and S-DALK (n = 30) groups at 15 months was 7.8±4.4 D and 6.3±5.0 D, respectively (p = 0.282) with an adjusted mean difference of 1.3 D (95% CI -1.08,+3.65). Mean SIA (arithmetic) was 9.2±7.8 and 8.8±5.4 D, respectively (p = 0.838) with a mean difference of 0.4 D (95% CI -3.13,+3.85). In an analysis of successful DALK cases only, mean postoperative astigmatism in the FE-DALK (n = 24) and S-DALK (n = 20) groups at 15 months (after excluding 4 eyes with AEs) was 7.3±4.4 and 6.2±4.9 D, respectively (p = 0.531) with an adjusted mean difference of 0.9 D (95% CI -1.94,+3.71). Mean SIA (arithmetic) was 9.1±7.8 and 7.9±4.6 D, respectively (p = 0.547) with a mean difference of 1.2 D (95% CI -2.70,+5.02). Comparison of secondary outcomes showed only weak statistical evidence. Conclusions In this randomized controlled trial, FE-DALK and S-DALK showed comparable functional and anatomical outcomes.