Evaluation of excimer laser photorefractive keratectomy for treatment of myopia and myopic astigmatism / 眼科新进展

ABSTRACT

Objective To evaluate the efficacy and accuracy of photorefractive keratectomy(PRK) for myopia and myopic astigmatism.Methods SVS APEX PLUS excimer laser with a wave length of 193nm(Summit Technology Inc.Waltham,Mass,USA) was applied.Three hundred and sixteen myopic eyes of 168 patients were treated with PRK from Suptember 1996 to October 1997,and 260 eyes(84%) of 150 patients were followed-up for more than three month,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 -10.00D(mean -4.67D± 1.63D),and astigmatism ranged from 0 to -2.00D(mean -0.33D±0.45D). The patients were divided into two groups according to the refractiongroup A(from -1.25D to -5.90D) and group B(from -6.00D to -10.00D).The number of eyes in the two groups were 220 and 40,respectively.Results In group A,After 10 days,68.9% had the uncorrected visual acuity(UCVA) equal to or one line better or lower than the preoperative best corrected visual acuity(BCVA).After 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,after 10 days,1,3,6 and 12 months,UCVA equal to or one line better or lower than the preoperative BCVA occurred in 35.9%,83.0%,87.0%,86.0% and 84.0% of the patients respectively. Most of the haze showed 0.5～1 grades except 3 eyes with the haze of 2 grade at 3 or 6 months and it changed to l and 0.5 grade respectively at one year.after 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.Conclusion We found that the 193nm excimer laser PRK is a predictable,safe,stable,and effective refractive surgery for correcting myopia up to-10.00D in Chinese patients,and the effect is better in myopia lower than -6.00D.