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Excimer laser photorefractive keratectomy for myopia: results in 1165 eyes. Italian Study Group.

BACKGROUND
We report the results of a prospective study conducted in Italy to evaluate the efficacy, safety, predictability, and complications of excimer laser photorefractive keratectomy for the correction of myopia. METHODS. Photorefractive keratectomy was performed on 1236 myopic sighted eyes in 16 centers, using the Summit Excimed 193 nm excimer laser. The attempted correction ranged from -0.80 to -25.00 diopters (mean, -7.83 +/- 3.88 D). The population was divided into three groups of attempted correction: between -0.80 and -6.00 D, between -6.10 and -9.90 D, and between -10.00 and -25.00 D. We report the data of 1165 eyes at 1 month, 970 eyes at 3 months, 752 at 6 months, and 330 at 12 months. At each visit, we evaluated (1) the refractive changes over time; (2) the difference between attempted and achieved correction; (3) uncorrected and best spectacle corrected visual acuity; and (4) haze.


RESULTS
Twelve months after surgery, the spherical equivalent refractive error in 146 eyes with attempted correction of -0.80 to -6.00 D was -0.52 +/- 1.04 D; 104 eyes (71.2%) were within +/- 1.00 D of attempted correction. In 145 eyes with attempted correction of -6.10 to -9.90 D, the spherical equivalent refractive error was -1.66 +/- 1.88 D; 50 eyes (34.5%) were within +/- 1.00 D of attempted correction. The spherical equivalent refractive error in 39 eyes with attempted correction of -10.00 to -25.00 D was -1.86 +/- 3.47 D; 11 eyes (28.2%) were within +/- 1.00 D of attempted correction. Eight eyes (2.4%) lost two or more Snellen lines of best spectacle corrected visual acuity. None of the treatments caused severe postoperative complications, or scarring.


CONCLUSIONS
Photorefractive keratectomy proved safe and effective, but highly predictable only in the correction of myopia up to -6.00 D.