CLINICAL ANALYSIS OF EXCIMER LASER PHOTOREFRACTIVE KERATECTOMY FOR TREATMENT OF MYOPIA AND MYOPIC ASTIGMATISM / 药物分析学报

ABSTRACT

To evaluate the efficacy and accuracy of photorefractive keratectomy (PRK) for myopia and myopic astigmatism .SVS APEX excimer laser with a wave length of 193 nm(Sumit Technology Inc. Waltham, Mass, USA) was applied. 316 myopic eyes of 168 patients were treated with PRK between September, 1996 and October, 1997, and 260 eyes (84%) of 150 patients were followed for more than three months, including male 68(116 eyes, 40.1%) and female 82(144 eyes, 59.9%). The preoperative spherical equivalent refractive errors ranged from -1.25D to -10.00 (mean -4.67±1.63D), and astigmatism ranged from 0 to -2.00D (means -0.33±0.45D). We divided the patients into two groups according to the referaction group A (from -1.25D to -5.90D) and group B(from -6.00 to -10.00D). The number of eyes in the two groups were 220 and 40 respectively. In group A, on the 10th day, 68.9% has the uncorrected visual acuity (UCVA) equal to or one line better or lower than the preoperative best corrected visual acuity (BCVA). In 1,3,6 and 12 months, 90%, 96%, 95% and 94% had the UCVA equal to or one line better or lower than the preoperative BCVA respectively. In group B, on the 10 th day, in 1,3,6 and 12 months, UCVA equal to or one line better or lower than the preoperative BCVA occurred in 35.9%, 83%, 87%, 86%, and 84% of the cases respectively. Most of the haze showed 0.5～1 grades except 3 eyes with the haze of 2 grade in 3 or 6 months and it changed to 1 and 0.5 grade respectively within one year. In 10 days and 1,3,6,12 months postoperatively, the corneal haze was noted in 32.9%, 84.8%, 62.8%,9.0% and 2.8% of the treated eyes respectively. We found that 193 nm excimer laser PRK was a predictable, safe, stable, and effective refractive surgery for correcting myopia up to -10.00D in Chinese patients, and the effect was better in myopia lower than -6.00D.