Abstract
Purpose :
The purpose of this study is to characterize the tissue surface roughness of femtosecond laser flap and deep lamella dissection using white light interferometer.
Methods :
Two femtosecond laser setups with wavelengths near ~1 um were used in this study. Setup#1 had a pulse energy smaller than 0.2 μJ, and a focus spot diameter smaller than 1.3μm; Setup#2 had a pulse energy smaller than 0.7 μJ, and a spot diameter greater than 1.6 um. Porcine eye globes were used for this study. Flap cut and deep lamellar dissections were programmed and executed on the porcine corneas. A Contour-GT Interferometer (manufactured by Bruker Inc.) was used to characterize the dissected tissue surface roughness. White light interferometer technique doesn’t require sample fixation and conductive coating, and can be conveniently used to measure the tissue surface roughness.
Results :
Different types of dissections were evaluated using the Bruker interferometer in order to have a quantitative surface roughness comparison for the two setups and for different laser parameter settings. Mean Roughness and Root Mean Square (RMS) Roughness were evaluated over the complete 3D surface, respectively. In general we obtained smoother surface for dissections done with lower pulse energy and smaller spot separation. For example, for a 400 um deep lamellar dissection, the Mean Roughness of the surface dissected by Setup#1 is 5.992μm, and RMS Roughness of 1.918μm; while the Mean Roughness for the surface dissected by Setup#2 is 2.930 μm, and RMS Roughness of 0.175μm.
Conclusions :
The white light interferometer is proven to be a convenient tool for characterizing the tissue surface roughness. Using this approach, we found that the femtosecond laser setup with smaller pulse energy and tighter focus spot produce relatively smoother tissue surface.
© 2015 Abbott Medical Optics Inc. sc2015rf0024
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.