EXCIMER-LASER PHOTOREFRACTIVE KERATECTOMY FOR HIGH MYOPIA

One hundred and thirty-three eyes of 103 patients had photorefractive keratectomy with a slit scan mode excimer laser for myopia ranging fro m -6.00 to -22.00 diopters (D). The epithelium was removed with 20% et hanol, and the ablation was done with a tapered profile surrounding th e optical zone. Patients were divided into two groups based on preoper ative myopia: Group A, -6.00 D to -12.00 D (88 eyes); Group B, -12.50 D to -22.00 D (45 eyes). In Group A, mean preoperative refraction was -9.59 +/- 1.79 D. Mean postoperative refraction was -0.29 +/- 1.47 D a t one month, -0.85 +/- 1.68 D at three months, -1.17 +/- 2.04 D at six months, and -0.56 +/- 0.74 D at one year. Anterior stromal haze was g reatest at the end of the first month; it diminished thereafter. This haze did not reduce the best corrected visual acuity in any eye in Gro up A. Mean preoperative refraction in Group B was -14.69 +/- 5.27 D. M ean postoperative refraction was -1.34 +/- 2.02 D at one month, -0.76 +/- 2.08 D at three months, -3.88 +/- 2.32 D at six months, and -5.50 +/- 5.00 D at one year. Three eyes in Group B lost one or two lines of best corrected visual acuity as a result of severe stromal haze and e pithelial scarring. Group A's results were similar to those obtained i n eyes with low myopia. In Group B, although a percentage of eyes obta ined fairly good results, the lower degree of predictability and large variation in the results suggest that using this technique is unadvis able in eyes with extremely high myopia except in selected cases.