Comparative study of ablation profiles of six different excimer lasers.
OBJECTIVE
To compare the morphological features of photorefractive ablations produced by six different excimer lasers.


METHODS
A spherocylindrical photoablation (-2.00 -2.00 x 90 degrees; 6-mm optical zone) was performed on regular fluence plates with six excimer lasers: Bausch & Lomb Technolas 217C, Schwind Esiris, Kera Technology Isobeam D200, Ladarvision 4000, Zeiss Meditec MEL 70 G-Scan, and Visx Star S3. Morphometric analysis of the fluence plates provided superficial measurements of the ablated areas.


RESULTS
Two areas were identified visually: a central area with a complete ablation of the metallic surface layer and a surrounding area with a partial ablation. The dimensions of the ablated areas were highly variable in the lasers tested. The major differences appeared in the total ablated area (ranging from 38.55 mm2 [Schwind] to 81.94 mm2 [Bausch & Lomb] and in the peripheral to total area ratio (ranging from 36.95% [Schwind] to 59.51% [Ladarvision]).


CONCLUSIONS
Large differences appeared in the superficial dimensions and contours of the ablations produced by different excimer lasers for the treatment tested in this study. It remains unknown how these different ablation patterns induce the same optical correction, but we assume that the depth of the ablation compensates for the differences in the surface extension of the ablated areas.
Canals
Marc
M
Institut Oftalmologic Integral, Ocular Morphology Unit, Medical School, University of Barcelona, Barcelona, Spain. marccanals@ub.edu
Elies
Daniel
D
Costa-Vila
Jesus
J
Coret
Andreu
A
D003315:Cornea / Q000601:surgery*; D006801:Humans; D054018:Lasers, Excimer; D008954:Models, Biological; D018903:Photorefractive Keratectomy / Q000295:instrumentation / Q000592:standards*; D019904:Polymethyl Methacrylate
D019904:Polymethyl Methacrylate