Observation Of Long-term Effect Of Excimer Laser Photorefractive Surgery

Refractive error is a common ophthalmic symptom and a social medical problem. With science technology developing and further studying in the excimer laser, the photorefractive surgery has been used rationally and rapidly. After 10 years'basic researches and clinical practices, the concept and clinical outcome of the excimer laser photorefractive surgery has been accepted widely, but there exist many shortcomings and problems such as visual quality and optic problems which have been recognized gradually. In the study, we analyzed the outcomes of PRK and LASLK patients retrospectively and discussed the long term effects of the two excimer laser keratectomy surgeries.Objective To observe visual acuity, diopter, complication and visual quality in patients treated with PRK and LASIK, and to evaluate the long-term clinical effects of them.Methods 219 eyes of 116 patients with myopia were treated by the PRK and 70 eyes of 39 patients with myopia were treated by the LASIK from Nov 1996 to Apr 1998 in our hospital . In the PRK group,according to the mean preoperative spherical equivalent refraction, the subjects were divided into 3 groups , group A: - 1. 00～-3. 00D ,53 eyes ; group B: - 3. 125～- 6. 00D ,125 eyes ; group C: -6. 125～- 16. 00D ,41eyes. And in the LASIK group, patients were also divided into 3 groups according to their mean pre- operative spherical equivalent refraction: group D: -3.00～-6.00D,17 eyes, group E: -6.125～-10.00D,33 eyes, group F: -10.125～-20.00D,20 eyes. The patients were investigated with 10 to 12- year follow-up . The results of visual acuity, diopter, complication and visual quality were concluded and analyzed.Results(1) PRK group: After 10 to 12 years, the percents of the patients with postoperative UCVA≥0.5 in PRK A, B, C groups were 100 %,100%,90.24% ;The percents of the patients with postoperative UCVA≥1.0 in A, B, C groups were 84.91 %,80.80 %,26.83%; In A,B,C groups, 92.45%,74.4%,31.71% patients'diopter were within±1. 00D. The percents of the patients whose best corrected visual acuity were equal to or above the best corrected visual acuity before the surgery were 98.11%,98.4%,92. 2 % in A,B,C groups;Synthetic satisfaction level was 90.52% for PRK.(2) LASIK group: After 10 to 12 years, the percents of the patients with postoperative UCVA≥0.5 in LASIK D,E,F groups were 100 %,84.77%,60.7%;The percents of the patients with postoperative UCVA≥1.0 in D,E groups were 70.59 %,21.21%; In D,E,F groups, 88.24%,72.73%,40% patients'diopter were within±1. 00D . The percents of the patients whose best corrected visual acuity was equal to or above the best corrected visual acuity before the surgery were100%,93.94%,75 % in D,E,F groups;Synthetic satisfaction level was 87.18% for LASIK.(3) None of the cases showed Haze at first class, secondary keratinous, corneal ectasia, retina detachment. Conclusion PRK and LASIK are effective and safe methods for correcting myopia, the correlation among spherical equivalent refraction, the predictability and the stability are negative. Early postoperative clinical effects of LASIK in high myopia is obvious. But there is no significant difference between the LASIK and PRK in long-term curative effect . PRK is a more effective procedure to improve visual quality compared to LASIK.Both of them showed long-term curative effects.