Nonmechanical posterior lamellar keratoplasty using the femtosecond laser (femto-plak) for corneal endothelial decompensation

Abstract

Purpose: To assess the potential of a short pulsed laser to cut a posterior graft and bed for posterior lamellar keratoplasty (PLAK).

Design: Experimental study.

Methods: Using the laser FEMTEC (20/10 Perfect Vision, Heidelberg, Germany), posterior lamellar dissections (wave length approximately 1 microm, pulse energy < 10 microJ, spot size <10 microm, repetition rate 12.5 kHz, 6-mm-7 mm diameter, 31 s and 90 s) were performed in 18 freshly enucleated porcine eyes and 10 human donor corneas starting from the anterior chamber and ending with the lamellar bed.

Results: Before removal, 50 microm to 500 microm-thick flaps were delineated by partly confluent gas bubbles (maximum 2-mm long) with minute tissue bridges (typically 5- to 10 microm) in between. Scanning electron microscopy displayed smooth cut surfaces and rectangular corners with minor remaining tissue bridges (approximately 5 microm). By transmission electron microscopy, the cut edges were lined by a delicate, electron-dense layer (5 nm-10 nm in width) and essentially normal adjacent collagen fibers.

Conclusions: Femtosecond laser technology seems to offer a promising approach to minimally invasive posterior lamellar keratoplasty (femto-PLAK) through small tunnel incisions in corneal endothelial diseases.