LASEK矫治薄角膜中低度近视远期效果

目的评价准分子激光上皮下角膜磨镶术（LASEK）矫治薄角膜（中央角膜厚度〈500μm）中低度近视的远期效果和安全性。方法回顾分析LASEK矫治中低度近视术后5～7年，对比术前薄角膜者与正常角膜厚度者的屈光度、视力、对比敏感度、眩光对比敏感度、角膜内皮细胞、角膜地形图。结果薄角膜组27例52眼，正常角膜厚度组31例62眼。两组术后随访均未见圆锥角膜病例。术后矫正视力均≥1．0。裸眼视力：薄角膜组≥1．0者49眼（94．23％），〈1．0者3眼；正常角膜组≥1．0者58眼（93．55％），〈1．0者4眼（x^2=0．0228，P〉0．05）。角膜Haze：薄角膜组0级49眼（94．23％），0．5级3眼；正常角膜组0级60眼（96．77％），0．5级2眼（x^2=0．4416，P〉0．05）。角膜内皮细胞形态两组均多为六角形，形态较一致，细胞边缘整齐；平均角膜内皮细胞密度：薄角膜组（2330±294）／mm^2，正常角膜组（2413±320）／mm^2（t=1．4310，P〉0．05）；平均角膜内皮细胞面积：薄角膜（420±78）μm^2，正常角膜组（447±92）／μm^2（t=1．6875，P〉0．05）。两组术后各空间频率对比敏感度、眩光对比敏感度均差无差别（P〉0．05）。结论LASEK矫治薄角膜中低度近视安全，效果稳定，未见圆锥角膜并发症。

Long-term effect of LASEK for the treatment of low to moderate myopia with thin cornea

Objective To evaluate the long term effect and safety of laser subepithelial keratomileusis( LASEK)for the treatment of low to moderate myopia with thin cornea( central corneal thickness ＜ 500　μm) Methods To analyze patients with low to moderate myopia in 5 -7 years after LASEK,and compare　the refraction,visual acuity,contrast sensitivity,glare contrast sensitivity,corneal endothelium and corneal　topography between pateints with thin cornea and normal thickness cornea.Results Thin cornea group had　27 cases (52 eyes).Normal thickness cornea group had 31 cases (62 eyes).No keratoconus had been observed during the follow-up period in the two groups.The corrected visual acuity of both groups were ≥1.0 ;In the thin cornea group,49 eyes' uncorrected visued acuity were ≥ 1.0,and 3 eyes were ＜ 1.0.In the　normal cornea group,58 eyes' uncorreeted visued acuity were ≥ 1.0,and 4 eyes were ＜ 1.0 (x2 ＝ 0.0228,P ＞ 0.05).In the thin cornea group,49 eyes had 0 degree of cornea Haze,and 3 eyes had 0.5 degrees of　cornea Haze.On the other hand,in the normal thickness cornea group,60 eyes had 0 degree of cornea　Haze,and 2 eyes had 0.5 degrees of cornea Haze(x2 =0.4416,P ＞ 0.05 ).The shapes of the corneal endothelium of bothgroups were quite consistent and appear to be hexagonal,and the cell edge was neat.The average endothelial cell density:(2330±294)/mm2 in the thin cornea group,and (2413 ±320)/mm2 in the　normal corneal thickness group; The average endothelial cell area:(420 ± 78 )μm2 in the thin cornea group,and (447 ± 92 ) μm2 ( t =1.6875,P ＞ 0.05 ) in the normal thickness cornea group.The contrast sensitivity of　two groups with or without glare condition had significant difference for every spatial frequencies (P ＞ 0.05 ).Conclusion LASEK for the treatment of low to moderate myopia with thin cornea is tested to be safe,stable　and with no keratoconus.