低中度近视配戴OK镜2年观察

Clinical observation of orthokeratology lens on low, moderate myopia correction after 2 years

目的观察角膜塑形镜（orthokeratology，OK）矫正近视的临床效果，评价其减缓近视度数增长的疗效及长期配戴的安全性。方法回顾性病例研究。对2010年4月至2010年8月在中国医科大学眼科医院就诊的73例（143只眼）低、中度近视患者观察，其中45例（87只眼）配戴OK镜的患者作为实验组，28例（56只眼）配戴框架眼镜的患者作为对照组。根据初诊时近视程度将实验组再分为两组：A组43只眼（近视≤-3．00D），B组44只眼（-3．00D〈近视≤-6．00D）。实验组于戴镜前、戴镜1天（8～10h）、1周、1个月、3个月、半年、1年、1年半、2年，进行裸眼视力检查。于戴镜前、戴镜2年后验光，测眼轴长度、角膜厚度、角膜内皮细胞密度及眼压检查。对照组于戴镜前和戴镜2年行电脑验光、主觉验光。戴镜前后各值比较采用配对t检验，各组间比较采用单因素方差分析，以P〈0．05为差异有统计学意义。结果实验组戴镜1天后裸眼视力均明显提高：A组戴镜1周平均视力达1．0以上，戴镜1年半视力开始下降，需重新试配，更换镜片。B组戴镜1周平均视力达0．8以上，戴镜1年视力开始出现下降，需重新试配，更换镜片。实验组戴镜2年后角膜垂直曲率和水平曲率均比戴镜前变平，且差异有统计学意义（P〈0．05）。实验组戴镜2年后近视度数比戴镜前增长（0．65±0．58）D，与对照组戴框架镜2年后近视度数增长（2．19±0．61）D比较，差异有统计学意义（F=228．64P〈0．05）。A组戴镜2年眼轴增长（0．45±0．28）mm，与戴镜前比较差异有统计学意义（t=9．834，P=0．000，P〈0．05），B组戴镜2年眼轴增长（0．34±0．33）mm，与戴镜前比较差异有统计学意义（t=2．570，P=0．014，P〈0．05），两组眼轴变化比较差异有统计学意义（F：5．360，P〈0．05），OK镜对低、中度近视均有控制作用，对中度近视控制效果更明显。实验组戴镜2年后角膜厚度、角膜内皮细胞密度、眼压与戴镜前相比，差异均无统计学意义（P〉0．05）。结论低、中度近视患者长期配戴OK镜，大部分患者戴镜1周可获0．8以上裸眼视力，并可保持1年左右，其后视力稍有下降，需更换镜片。长期配戴可有效控制近视度数发展，中度近视比低度近视控制效果更明显，且均未引起角膜厚度、角膜内皮细胞密度和眼压的变化。

Objective To observe the clinical effects of orthokeratology lens （orthokeratology, OK） on the correction of myopia, to evaluate the effects and safety of long-term Ortho-K on the my- opia control. Methods A retrospective case study. Seventy-three cases （143 eyes） with low, and moderate myopia patients were divided into 2 groups, 45 cases （87 eyes） with the Ortho-K contact lens in the experimental group, and 28 cases （56 eyes） wearing spectacles in the control group. The experimental group was subdivided into 2 groups： 43 eyes in group A （myopias〈 -3.00D）, 44 eyes in group B （-3.00D〈 myopia ≤ -6.00D）, based on the diopters. The visual acuity （VA） of the exper- imental group were taken respectively at pre-wear, 1 day （8-10 hours）, 1 week, 1 month, 3 months, 6 months, 1 year, 1 and a half years, 2 years. The changes of axial length, corneal thickness, corne- al endothelial and intraocular pressure within 2 years with the Ortho-K contact lens in the experimen- tal group were compared. Refraction was measured in the control group pre-wearing and after 2 years. Data were analyzed by a paired t test before and after wearing glasses, Data between groups were compared with single factor analysis of variance, A P value of 0.05 or less was considered sta- tistically significant. Results In the experimental group, VA improved significantly after wearing glasses a day. In group A, VA was 1.0 after a week, which decreased after 1 and a half of years, and then needed to test again and replace lenses. In group B, the mean VA was 0.8 after a week, which decreased after 1 and a half of years, and then needed to test again and replace lenses. The vertical and horizontal curvature of cornea in the experimental group became flatter than before, and the difference was statistically significant （P 〈0.05） after 2 years. The myopic degree in the experi- mental group increased （0.65 ±0.58） D 2 years later, and the control group with spectacles in- creased （2.19±0.61） D, which showed statistically significant difference （F=228.64, P 〈0.05）. The axi- al length in group A growth increased 0.45±0.28 mm2 years later, and the difference was statistically significant compared with before （t=9.834, P =0.000, P 〈0.05）. The axial length in group B growth increased 0.34±0.33 mm 2 years later, and the difference was statistically significant compared with before （t =2.570, P =0.014, P 〈0.05）. The axial length variation of two groups had statistical signifi- cance difference after 2 years （F =5.360, P 〈0.05）. Ortho-K could control the development of low and moderate myopia, the effect was significantly compared with the moderate myopia. In the experi- mental group, there were no statistically significance in corneal thickness, corneal endothelial cell den- sity, intraocular pressure after 2 years, compared with which measured before （P 〉0.05）. Conclu- sions Most of the low, moderate myopia patients wearing Ortho-K long-term later can get visible VA more than 0.8, and can keep for about a year, when the visual acuity decrease slightly, lens need to be changed. The control effect of moderate myopia is significantly better than low myopia after Long-term wear, and can not cause the changes of corneal thickness, corneal endothelial cell density and intraocular pressure.