To compare outcomes of femtosecond-enabled deep anterior lamellar keratoplasty (FE-DALK) and standard deep anterior lamellar keratoplasty (S-DALK).
An open label, randomized controlled trial (Kensington Eye Institute, Toronto, ON, 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.
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.
In this randomized controlled trial, FE-DALK and S-DALK showed comparable functional and anatomical outcomes.
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The datasets generated and analyzed during the current study are not publicly available to protect individual privacy but are available from the corresponding author on reasonable request following the approval of the University of Toronto Research Ethics Board.
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We would like to acknowledge Professor Noel Alpins for his assistance and guidance in the planning of vector analysis in the study, and Ms. Fei Zuo for her assistance in data analysis.
This study is funded by Kensington Research Institute.
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Sorkin, N., Hatch, W., Mimouni, M. et al. A randomized controlled trial comparing femtosecond-enabled deep anterior lamellar keratoplasty and standard deep anterior lamellar keratoplasty (FEDS Study). Eye (2023). https://doi.org/10.1038/s41433-023-02387-1