Central photorefractive keratectomy for myopia. The blind eye study
M. B. McDonald, J. M. Frantz, S. D. Klyce, R. W. Beuerman, R. Varnell, C. R. Munnerlyn, T. N. Clapham, B. Salmeron and H. E. Kaufman
LSU Eye Center, Louisiana State University Medical Center School of Medicine, New Orleans.
Prior to undertaking a study in sighted human eyes, we performed
photorefractive keratectomy with the 193-nm excimer laser for the
correction of myopia in nine legally blind eyes to evaluate safety,
efficacy, predictability, and stability. In most cases, reepithelialization
was complete by 5 days after surgery; no recurrent erosions were seen. By
the end of the 6-month study, all of the corneas had a 0 or 1+ clarity
score, on a scale of 0 (clear) to 5+ (opaque). Keratometry and pachometry
demonstrated stable flattening of the corneas. One month after surgery,
changes in refraction evaluated by retinoscopy showed fair predictability,
with no significant increase in refractive or keratometric astigmatism,
followed by some regression of effect by the end of the study, possibly
caused by anatomical remodeling. The amount of regression appeared to be
directly related to the amount of correction intended, suggesting that this
effect would not be clinically important in the treatment of mild to
moderate myopia.
