准分子激光原位角膜磨镶术后屈光度数回退的原因分析

目的　探讨准分子激光原位角膜磨镶术 (laserinsitukeratomileusis,LASIK)后屈光度数回退的原因。方法　将 2 5 0例 (40 8只眼 )近视患者 (- 6 0 0～ - 15 0 0D)按屈光度数分为A组 194只眼 (- 6 2 5～ - 10 0 0D)和B组 2 14只眼 (- 10 2 5～ - 15 0 0D)行LASIK ,记录术后视力、屈光度数、角膜厚度和角膜激光切削区直径 ,并进行统计学分析。术后平均随访时间 1年。结果　 (1)A组 :正常术眼 (术后屈光度数 <- 1 0 0D) 173只眼 (89 2 % ) ,术前平均角膜厚度为 (5 4 9 5± 31 5 ) μm ,术中平均激光切削直径为 (4 96± 0 35 )mm ,术后屈光度数为 +0 5 0～ - 0 75D ;回退术眼 (术后屈光度数≥ - 1 0 0D) 2 1只眼 (10 8% ) ,术前平均角膜厚度为 (5 4 7 5± 37 0 ) μm ,与正常术眼比较差异无显著意义 (P >0 0 5 ) ;术中平均激光切削直径为 (4 6 4± 0 4 1)mm ,与正常术眼比较差异有非常显著意义(P <0 0 1) ;术后平均屈光度数为 (- 1 33± 0 5 8)D。 (2 )B组 :正常术眼 136只眼 (6 3 5 % ) ,术前平均角膜厚度为 (5 6 0 9± 30 9) μm ,术中平均激光切削直径为 (4 5 1± 0 2 8)mm ,术后屈光度数为 +0 5 0～- 0 75D ;回退术眼 78只眼 (36 5 % ) ,术前平均角膜厚度为 (5 38 0± 31 0 ) μm ,

An analysis of regression after laser in situ keratomileusis for treatment of myopia

OBJECTIVE: To evaluate the regression relevant reasons of laser in situ kertomileusis (LASIK) for treatment of myopia. METHODS: Four hundred and eight eyes of 250 patients with myopia who received LASIK were studied. They were divided into 2 groups according to preoperative diopters (-6.25- -10.00 D in 194 eyes; -10.25 -15.00 D in 214 eyes). The mean follow-up was 12 months, and the results of the postoperative visual acuity, refractive diopter, corneal thickness and the diameter of the ablation zone were statistically analyzed. RESULTS: (1) A group: There were 173 normal operative eyes (89.2%, post-operative diopter < -1.00 D), the mean pre-operative corneal thickness was (549.5 +/- 31.5) microm, the mean intra-operative laser ablation diameter was (4.96 +/- 0.35) mm, and the post-operative refractive diopter was +0.50- -0.75 D. The regressive operative eyes: There were 21 eyes (10.8%, post- operative diopter >/= -1.00D), the mean preoperative corneal thickness was (547.7 +/- 37.0) microm (P > 0.05 in comparison with that of the normal operative eyes), the mean intra-operative laser ablation diameter was (4.64 +/- 0.41 ) mm (P < 0.01 in comparison with that of the normal operative eyes), and the mean post-operative diopter was (-1.33 +/- 0.58)D. (2) B group: There were 136 normal operative eyes (63.5%), the mean pre-operative corneal thickness was (560.9 +/- 30.9) microm, the mean intra-operative laser ablation diameter was (4.51 +/- 0.28) mm, and the post-operative diopter was +0.50- -0.75 D. The regressive operative eyes: There were 78 eyes (36.5%), the mean pre-operative corneal thickness was (538.0 +/- 31.0) microm (P < 0.01 in comparison with that of the normal operative eyes), the mean intra-operative laser ablation diameter was (4.22 +/- 0.34) mm (P < 0.01 in comparison with that of the normal operative eyes), and the mean post-operative diopter was (-1.99 +/- 1.01) D. CONCLUSIONS: In cases with small laser ablation diameter and the thin pre-operative corneal thickness of high myopia, after the surgery refractive regression is easy to occur. Some modification of the surgical algorithms and laser nomogram will help to improve predictability and reduce regression.