The Property Of Corneal Asphericity And Its Effect Of Reformation On Vision Quality In Myopes

Objective: To investigate these questiones:(1) The range and property of the anterior corneal asphericity factor Q in myopic eyes.(2) The Q's related factors in myopic eyes.(3) The reformation of Q before and after myopic LASIK,and its effect on vision quality.Methods: (1) To examine the topography and observe the range and property of the Q on 1000 myopic eyes before LASIK by ALLEGRO topolyzer. And analyzed the relationship between Q value with refractive error,cornea radius of curvature and cornea Zernike polynomial.(2) using an A-Scan ultrasonic to measure the axial length,anterior chamber depth,lens thickness,vitreous chamber depth, cornea thickness,ocular pressure and diameter of cornea, and analyze its relationship with Q.(3) To observe the changes of Q between standard and Q value asjust myopic LASIK before and 1,3 month posteroperation. And compare its vision quality with contrast sensitivity,cornea Zernike polynomial and subjective symptoms. (4) Using the SPSS 12.0 to analyze the dataes.Results: (1) The range of Q value average was -0.14～ -0.30 on 1000 myopic eyes. The Q value is diversities between individuals. The Q value on the cornea of temporal, inferior and horizontal is more positive than nasal,superior and vertical. (2) The Q₃₀ value is more negative in high myopia than in low and moderate myopia.(3) With the increasing of R,axial length, vitreous chamber depth and decreasing of anterior chamber depth, the Q value is more negative.(4) With the increasing of horizontal diameter of cornea, the horizontal of Q value is more positive.(5) There is no relationship between cornea thickness,ocular pressure and Q.(6) There is no statistic difference between the left eye and the right eye.(7) The female of Q value on the cornea of superior and vertical is more negative than male. (8) There's relationship between Q₃₀ value and cornea Zernike polynomial, especially Z₄⁰ and Z₂⁰.(9) The Q value is 0.65 ,0.64 separately between standard and Q value asjust myopic LASIK after postoperation. There's curve relationship between the Q value and ablation depth. The uncorrected vision acuity(UCVA),the contrast sensitivity of 6c/d,18c/d under mesopic environment without glare are increasing in Q adjust...