Femtosecond Laser-Assisted Hemi-Automated Lamellar Keratoplasty: A Hybrid Technique

Hemi-automated assisted lamellar keratoplasty (HALK) is a procedure for corneas with anterior to mid-stromal pathology, preserving the healthy endothelium. The manual trephination step and subsequent manual dissection in conventional HALK can affect stromal depth and accuracy. We evaluated the use of the femtosecond laser in hemi-automated anterior lamellar keratoplasty (FSL-HALK), for managing corneal stromal opacities and dystrophies.

This is a retrospective case series performed in a Singapore tertiary eye hospital.

11 eyes with corneal scarring, post-infectious keratitis, or stromal dystrophy underwent FSL-HALK. Preoperative and postoperative best-corrected visual acuity (BCVA), refractive cylinder were analyzed at 1, 6, 12 months, and final follow-up. Surgical complications and graft failure rates were assessed.

A "donut" ablation profile was undertaken with the FSL, with subsequent manual dissection of the remaining recipient bed.

At last follow up, mean LogMAR BCVA improved significantly from 0.58 ± 0.25 preoperatively to 0.38 ± 0.24 postoperatively (p = 0.029). Mean postoperative refractive cylinder was 3.45 ± 1.65 D. The long-term graft survival rate was 90.9% (one failure). One intraoperative microperforation of Descemet's membrane occurred without aborting the procedure. One eye developed significant interface haze, attributed to the use of an electron-beam–irradiated donor graft, and later underwent deep anterior lamellar keratoplasty (DALK). No femtosecond laser-specific complications (e.g., opaque bubble layer, vertical gas breakthrough) were observed.

FSL-HALK is a safe and effective hybrid technique, demonstrating significant visual improvement, a high rate of graft survival, and a favourable complication profile. It offers an alternative to conventional HALK and DALK for midstromal corneal pathologies.