In:
Journal of Refractive Surgery, SLACK, Inc., Vol. 16, No. 3 ( 2000-05), p. 341-348
Abstract:
ABSTRACT PURPOSE: Examination of morphology in corneal ablation induced by a q-switched ErrYSGG (2.79 µm) laser and a free-running Er:YAG laser (2.94 µm). METHODS: Defined ablation of 6-mm diameter and 15, 30, 55, 90, and 120-µm depth was performed on freshly enucleated swine eyes. ErrYSGG laser parameters: fluence 1.6 J/cm2, frequency 6 Hz, spotsize 465 µm FWHM, scanning-mode, pulse number 1520 to 6210. Er:YAG laser parameters: fluence 3 J/cm2, frequency 1.5 Hz, spotsize 6 mm, wide area ablation, pulse number 2 to 13. Corneal morphology was analyzed by gross photography, histology, scanning electron microscopy, and scanning nearfield acoustic microscopy. RESULTS: Histology showed thermal damage of 5 to 15 µm in depth caused by the ErrYSGG laser in comparison with 10 to 20 µm by the Er:YAG laser. Average roughness of the ablated surface measured with scanning nearfield acoustic microscopy was 20 to 40 µm for the Er: YSGG laser and 5 to 15 µm for the Er:YAG laser. These data confirm the subjective impression of images created by scanning electron microscopy and gross photography. CONCLUSIONS: Although the Er:YAG laser system appeared to demonstrate a smoother corneal surface than the q-switched ErrYSGG laser, the thermal damage in either case poses a potential limitation for clinical use in lamellar refractive surgery. [J Refract Surg 2000;16r341-348]
Type of Medium:
Online Resource
ISSN:
1081-597X
DOI:
10.3928/1081-597X-20000501-08
Language:
English
Publisher:
SLACK, Inc.
Publication Date:
2000
