Abstract
Purpose:
In advanced keratoconus’ surgeries, lamellar cuts using femtosecond laser are usually uncertain. This is explained by the thinness of the corneal stroma, frequently misshapen during applanation, which sometimes limit the possibilities of non-penetrating lamellar cuts. We evaluated the contribution of real-time Optical Coherence Tomography (OCT) associated with a curved applanation’s surface in the lamellar surgery of thin corneas.
Methods:
Cuts prepared on artificial anterior chambers of corneal grafts were realized with the femtosecond laser Victus (Bausch and Lomb) to evaluate the reproducibility of cuts on full thickness and pre-finned human corneas. The Victus laser was then used for pre-cuts of anterior corneal lamellae during deep anterior lamellar keratoplasty (DALK) of keratoconus.
Results:
Curved applanation and visualization with real-time OCT of the cuts’ depth enabled the realization of reproducible lamellar cuts on 200 microns thick corneas, without modifying the laser-cornea interface neither the use of masking agents.<br /> The realization of anterior lamellar corneal cuts was then realized during advanced keratoconus surgery. Real-time OCT visualization allowed controlling non-penetrating cuts, while the curved applanation allowed the absence of folds on the residual stroma.<br /> The air dissection technique according to Anwar permitted the achievement of the "big-bubble" in each case (3/3) and the realization of pre-descemetic lamellar grafts.
Conclusions:
Curved applanation of the laser-cornea interface and direct visualization of cuts with real-time OCT facilitate the realization of femtosecond laser-assisted deep anterior lamellar keratoplasty in advanced keratoconus.