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A randomized controlled trial comparing femtosecond-enabled deep anterior lamellar keratoplasty and standard deep anterior lamellar keratoplasty (FEDS Study)

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, 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.

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.

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Fig. 1: Femtosecond laser settings for the creation of a full-thickness mushroom configuration in the donor cornea.
Fig. 2: Femtosecond laser settings for the creation of a partial thickness mushroom configuration in the recipient cornea.
Fig. 3: CONSORT Flow Diagram.

Data availability

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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Acknowledgements

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.

Funding

This study is funded by Kensington Research Institute.

Author information

Authors and Affiliations

Authors

Contributions

NSo was responsible for designing the study, drafting the protocol, analysis planning, interpreting results, and drafting the manuscript. WH was responsible for designing the study, drafting the protocol, recruiting participants, collecting data, interpreting results, and revising the manuscript. MM was responsible for analysis planning, interpreting results and revising the manuscript. HFC was responsible for recruiting participants, collecting data, and revising the manuscript. DSR was responsible for recruiting participants, collecting data, and revising the manuscript. ARS was responsible for recruiting participants, collecting data, and revising the manuscript. MCB was responsible for recruiting participants, collecting data, and revising the manuscript. CCC was responsible for recruiting participants, collecting data, and revising the manuscript. KET was responsible for analysis planning, performing the analysis, interpreting results, and revising the manuscript. MP was responsible for designing the study, drafting the protocol, and revising the manuscript. VS was responsible for recruiting participants, conducting follow-up testing, collecting data, and revising the manuscript. NSi was responsible for designing the study, analysis planning, drafting the protocol, supervising study procedures, recruiting participants, collecting data, interpreting results, and revising the manuscript.

Corresponding author

Correspondence to Nir Sorkin.

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The authors declare no competing interests.

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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

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  • DOI: https://doi.org/10.1038/s41433-023-02387-1

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