Abstract
Purpose:
Develop an effective method for femtosecond (FS) laser deep anterior lamellar dissection resulting in a smooth plane
Methods:
30 human research corneas mounted on an artificial anterior chamber were treated with an IntraLase iFS 150 kHz femtosecond laser (Abbott Medical Optics, Santa Ana, CA) at a level of 40-70 microns anterior to Descemet membrane. Raster, spiral, or combined patterns were used with spot separations ranging from 4x4 to 10x10 microns and spot energies from 0.35 to 2.5 microJoules. Specimens were examined with biomicroscopy, scanning electron microscopy (SEM), OCT, and trypan blue/alizarin red endothelial staining.
Results:
The smoothest bed was obtained with multiple raster passes, each from a different direction. The maximum number of passes required was 6 with a spot separation pattern of 8x8 microns. Optimum pulse energy needed to be just above threshold, which for most corneas was typically 0.35 microJoules. Higher pulse energies and closer spot spacing yielded easier tissue separation but markedly more irregularity of the tissue plane, with visible ridges. Staining and SEM of the endothelium shows no evidence of damage from the laser pulses. A curved interface did not yield better results than a flat interface.
Conclusions:
A technique of very low energy, widely spaced and multiple pass FS laser lamellar dissection produces a smooth dissection in the deep stroma that may be useful for thin stroma DSAEK tissue preparation and for deep anterior lamellar keratoplasty.
Keywords: 578 laser •
741 transplantation