Femtosecond-Assisted Big Bubble: A Feasibility Study.

Purpose: To evaluate the feasibility of femtosecond laser-assisted (FA) tunnel creation as a pretreatment for creating a big bubble (BB) to pneumo-dissect the corneal stroma from Descemet membrane.

Methods: Five human cadaver eyes received pretreatment using a femtosecond laser. An intrastromal tunnel, along with a side cut, was achieved using customized femtosecond corneal disruption (custom mask). Before treatment, optical coherence tomography was performed and the intrastromal tunnel was intended to achieve a parallel orientation with respect to the corneal endothelial cell layer (50 µm above the endothelium). Surgical dissection of the side cut using a Sinskey hook was performed, followed by insertion of a deep anterior lamellar keratoplasty cannula into the tunnel and pneumo-dissection (BB). All corneas after treatment were prepared for histologic evaluation (light microscopy).

Results: FA pretreatment was successful in all 5 cadaveric corneas, and the BB was achieved in all eyes as well. Histologic evaluation of the corneas revealed complete separation of Descemet membrane and stroma in all eyes, with no remaining stroma attached to Descemet membrane and no signs of perforation.

Conclusions: FABB seems feasible because pneumo-dissection of the corneal stroma from Descemet membrane was achieved in all human cadaver corneas of this experimental study. Optical coherence tomography, corneal histology, and macroscopic evaluation revealed complete Descemet-stromal separation.