Some technical factors relating to the use of the VISX model 20/20 excimer laser for photorefractive keratectomy will be discussed and the way they affect the final optical correction will be demonstrated, as follows: (1) Discontinuation of nitrogen flow: improved corneal haze but induced a mean undercorrection of 0.8 D, 18 months postoperatively. (2) Discontinuation of the use of the fixation ring did not affect centration in a statistically significant fashion. (3) Enlargement of the optical from 5.0 mm to 6.0 mm zone did not affect the refractive outcome. Visual acuity was improved in eyes which had PRK done with a 6.0 mm optical zone.

Date Published: 22 May 1995
PDF: 8 pages
Proc. SPIE 2393, Ophthalmic Technologies V, (22 May 1995); doi: 10.1117/12.209858

Published in SPIE Proceedings Vol. 2393:
Ophthalmic Technologies V
Jean-Marie Parel; Qiushi Ren; Karen Margaret Joos M.D., Editor(s)