[Ablation on the undersurface of a LASIK flap. Instrument and method for continuous eye tracking]

Area of Science:

• Ophthalmology
• Refractive Surgery
• Corneal Surgery

Context:

• Iatrogenic keratectasia risk increases with thinner posterior stromal beds after LASIK.
• Undersurface LASIK flap ablations traditionally lack eye-tracker guidance, risking decentration.
• A novel instrument allows active eye-tracker use for flying spot laser ablation on LASIK flap undersurfaces.

Purpose:

• To report the first clinical results of a new method for centered laser ablation on the undersurface of LASIK flaps using an active eye tracker.
• To assess the feasibility and safety of enhancing LASIK procedures by ablating the flap undersurface.
• To mitigate the risk of iatrogenic keratectasia during LASIK enhancement procedures.

Summary:

• A modified repeat LASIK procedure utilized a novel flap holder with a visible marking for eye-tracker guidance.
• Flying spot laser ablation was performed on the flap undersurface, with cylinder axis mirroring for astigmatic corrections.
• The technique allowed centered ablations in all 12 treated eyes without decentration or loss of best spectacle-corrected visual acuity.

Impact:

• Centered LASIK flap undersurface ablations are feasible with the novel technique and instrument.
• This method avoids the increased risk of iatrogenic keratectasia associated with stromal enhancement.
• Good refractive outcomes were achieved for minor corrections, suggesting a safer LASIK enhancement option.