Objective To observe the changes in corneal astigmatism after patients are fitted with different ortho-k contact lens (CL) designs and the influence of these lenses on visual quality.Methods In a case-control study,corneal astigmatism,corneal topography,wavefront aberrations (Pentacam),visual acuity and visual disturbance symptoms were observed in three groups (groups A,B,C) before and after CL wear.Group A (30 eyes) had lower corneal astigmatism and wore a general ortho-k contact lens design that fit quite well; group B (30 eyes) had lower corneal astigmatism and wore a general ortho-k contact lens design that did not fit well and was obviously decentered; group C (31 eyes) had higher corneal astigmatism and wore toric ortho-k contact lenses with an acceptable fit.SPSS 16.0 statistical software was used to analyze the data.Results Changes in corneal astigmatism after fitting with the ortho-k CL:astigmatism increased in group B but was lower in groups A and C.Fourier analysis from corneal topography:increases in asymmetry for all three groups at 3 mm were (-0.393±0.329)D,(-4.050±2.084)D,and (-0.494±0.522)D,respectively,all at P＜0.001.Higher order aberrations in the three groups increased at 3 mm and were (-0.011±0.055)D (P＞0.05),(-0.635±0.441)D (P＜0.001) and (-0.055±0.082)D (P＜0.01).The three groups at 3 mm regular:differences in the comparison of astigmatism,asymmetry and higher order aberrations were statistically significant,F=79.862,F=83.882,F=54.265,respectively,all at P＜0.01.After fitting with ortho-k CLs,the total aberrations and total higher order aberrations for the three groups increased in varying degrees,with group B as the most significant.A comparison of the difference in aberrations:only the anterior surface of the spherical aberration had a statistically significant difference (F=18.048,P＜0.01).After the CLs were removed:in group A 36.7 ％ achieved a UVA of 1.2,50.0％ achieved 1.0 and 13.3％ achieved 0.8; in group B 36.7％ achieved 1.0,46.7％achieved 0.9-0.8,13.3％ achieved 0.6-0.5,and 3.3％ achieved 0.4; in group C 9.7％ achieved 1.2,51.6％ achieved 1.0,16.1％ achieved 0.9～0.8 and 22.6％ achieved 0.6.There were statistically significant differences in UVA between the three groups (x2=20.252,P＜0.01).Patients reported a variety of visual disturbance symptoms such as ghost,fringe,glare,etc.In group A,0％ reported visual disturbance symptoms,with 16％ in group C and 47％ in group B.Conclusion Ortho-k contact lens design and fitting significantly impact corneal astigmatism and visual quality.Appropriate ortho-k CL toric designs can be highly effective for improving the CL fitting and enhancing the corneal reshaping effect for some higher order corneal astigmatisms.%目的 观察不同设计角膜塑形镜配戴后角膜散光的变化,以及对视觉质量的影响.方法 病例对照研究.分3组观察戴镜前后的角膜散光、角膜地形图、角膜波前像差(Pentacam)、视力以及视觉干扰症状.A组30眼,低度角膜散光戴常规设计角膜塑形镜,获良好配适状态；B组30眼,低度角膜散光戴常规设计角膜塑形镜,配适状态不良,有明显偏位；C组31眼,中高度角膜散光戴toric设计角膜塑形镜,配适状态尚好.采用SPSS 16.0进行统计学分析.结果 戴镜后角膜散光B组增加,A组及C组有降低.角膜地形图傅立叶转换,3组非对称性散光增加3 mm区分别为(-0.393±0.329)D,(-4.050±2.084)D和(-0.494±0.522)D,P均＜0.01;3组高阶性散光增加3 mm区分别为(-0.011±0.055)D(P＞0.05),(-0.635±0.441)D(P＜0.01)和(-0.055±0.082)D(P＜0.01).3组3 mm区规则性散光、非对称性及高阶散光的差值比较有统计学意义(F=79.862、83.882、54.265,P均＜0.01).3组总体像差和总高阶像差,戴镜后均有不同程度增高,以B组最明显.各像差的差值比较中,仅前球差有统计学意义(F=18.048,P＜0.01).患者摘镜后裸眼视力,A组中36.7％为1.2,50.0％为1.0,13.3％为0.8,均无明显视觉症状；B组中36.7％为1.0,46.7％为0.9～0.8,13.3％为0.6～0.5,3.3％为0.4,47％有虚影、重影、眩光等视觉干扰症状；C组中9.7％为1.2,51.6％为1.0,16.1％为0.9～0.8,22.6％为0.6,16％有视觉干扰症状.3组视力比较差异有统计学意义(x2=20.252,P＜O.01).结论 角膜塑形镜的设计和配适状态明显影响角膜散光与视觉质量,适宜的Toric设计镜片可有效改善中高度角膜散光眼的配适,提高降低近视与散光度的角膜塑形效果.
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