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  • Laser automation may help optimize DALK outcomes

    Cornea/External Disease

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    Review of: Femtosecond laser assisted deep anterior lamellar keratoplasty for keratoconus: multi-surgeon results

    Gadhvi K, Romano V, Cueto L, et al. American Journal of Ophthalmology, in press

    This single-center, comparative, retrospective case series compared femtosecond laser-assisted big-bubble deep anterior lamellar keratoplasty (F-DALK) with manual non-laser DALK (M-DALK).

    Study design

    During this 3-year study, 58 eyes underwent F-DALK. For a historical control group, researchers used data from a previously published study to identify 326 eyes that underwent M-DALK. The primary outcome measures were rates of intraoperative perforation and conversion to penetrating keratoplasty (PK) and the percentage of patients who achieved corrected distance visual acuity (CDVA) of 20/40 or better.

    Outcomes

    Approximately 26% of F-DALK cases and 45% of M-DALK cases resulted in intraoperative perforation (P=0.006). Intraoperative conversion to PK occurred in 3% of the F-DALK arm compared with 25% of the M-DALK arm (P=0.001). After the removal of sutures, nearly 87% of F-DALK eyes achieved CDVA of 20/40 or better by 15 months compared with 84% of M-DALK eyes at 25 months. Corneal suture removal was performed earlier in F-DALK eyes than M-DALK eyes (62% vs. 22% at 12 months; P=0.001).

    Limitations

    Study limitations include a small sample size of F-DALK cases compared with M-DALK cases. In addition, surgeries were performed by both trainees and experienced surgeons, which may have influenced surgical outcomes. Finally, all F-DALK cases were performed with a standardized mushroom pattern with large diameter (9 mm) anterior cap and small diameter (6 mm) optical zone but it is not clear if these are the optimal settings for the F-DALK procedure. Future studies are necessary for validation.

    Clinical significance

    Manual DALK is a challenging technique for many corneal surgeons. Using a femtosecond laser to automate dissection of Descemet membrane for big-bubble DALK may improve success rates and improve visual outcomes.