Excimer photorefractive keratectomy for myopia.
OBJECTIVE
To study the safety, effectiveness, predictability, and stability of excimer laser photorefractive keratectomy (PRK) in 133 normally sighted eyes.


METHODS
An excimer laser was used with a fluence of 160 mJ/cm2 at a frequency of 5 Hz and an ablation zone of 5.0 mm. The effects of nitrogen purge at surgery and postoperative steroids were evaluated.


RESULTS
No significant complications occurred in any patient. After an initial over-correction, the refraction stabilized. The average results obtained at 6 months were maintained on successive examinations to 36 months. Analysis of their visual acuity in groups IIA, IIB, and III indicates that results at 6 months are predictive of final results at 1 to 3 years (P < 0.0001; r > 0.9). In myopia (1.00-6.00 diopters [D]) treated with the excimer laser, there was a trend toward improvement in results over the course of the study. In 60% in group IIA, 58% in group IIB, 71% in group III, and 88% in group III no nitrogen (no N2), +/- 1 D was obtained. For 20/40 or better uncorrected visual acuity, the outcome was 70% for group IIA, 67% for group IIB, 75% for group III, and 100% for group III no N2. Significant improvement was noted without nitrogen purge. No significant improvement was observed from steroid treatment as used.


CONCLUSIONS
In reducing myopia, PRK appears to be safe and effective. The results obtained are reasonably predictable and stable after 6 months. As more refinements are introduced, this procedure could become one of the most promising in refractive surgery.
University of Missouri-Kansas City School of Medicine, Department of Ophthalmology, Eye Foundation of Kansas City, MO 64108.
L W
LW
Piebenga
C S
CS
Matta
M R
MR
Deitz
J
J
Tauber
J W
JW
Irvine
F N
FN
Sabates
D000328:Adult; D001251:Astigmatism / Q000209:etiology; D015350:Contrast Sensitivity; D003315:Cornea / Q000601:surgery*; D003318:Corneal Opacity / Q000209:etiology; D004848:Epithelium; D005260:Female; D005469:Fluorometholone / Q000008:administration & dosage; D005500:Follow-Up Studies; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D011379:Prognosis; D014792:Visual Acuity; D014945:Wound Healing
D005469:Fluorometholone