中华眼视光学与视觉科学杂志
中華眼視光學與視覺科學雜誌
중화안시광학여시각과학잡지
CHINESE JOURNAL OF OPTOMETRY OPHTHALMOLOGY AND VISUAL SCIENCE
2014年
6期
368-371
,共4页
视光学%角膜前表面面型%椭球面拟合%Q值%波前像差
視光學%角膜前錶麵麵型%橢毬麵擬閤%Q值%波前像差
시광학%각막전표면면형%타구면의합%Q치%파전상차
Visual optics%Parameters of the anterior corneal surface%Ellipsoid fitting%Q value%Wavefront aberration
目的 采用椭球面角膜前表面面型研究中国人角膜的实际面型参数.方法 实验研究.选取40例(80眼)屈光手术前检查患者,用Levenberg-Marquardt方法对测量得到的角膜高度数据进行拟合,然后再通过坐标变换,得出角膜的参数.另外,采用t检验比较了球面拟合、旋转对称非球面拟和以及双二次曲面拟合下的角膜面型参数.结果 采用椭球面拟合,8 mm直径范围的均方根值低达(2.14±0.56) μm;拟合的稳定性好,标准偏差只有0.56 μm;而其他拟合方式均远低于以上的拟合精度.椭球面拟合时,角膜前表面曲率半径的平均值为(7.67±0.23)ram,相应的屈光度为(49.02± 1.44)D;角膜前表面的非球面系数(Q值)的平均值为-0.33±0.09;其他拟合方式下得到的曲率半径均比椭球面拟和的大(P＜0.01),而角膜前表面Q值的绝对值小于椭球面拟和下的Q值(P＜0.01).结论 角膜的实际屈光度较目前的公认值48 D大,而角膜的实际面型也更为扁长.
目的 採用橢毬麵角膜前錶麵麵型研究中國人角膜的實際麵型參數.方法 實驗研究.選取40例(80眼)屈光手術前檢查患者,用Levenberg-Marquardt方法對測量得到的角膜高度數據進行擬閤,然後再通過坐標變換,得齣角膜的參數.另外,採用t檢驗比較瞭毬麵擬閤、鏇轉對稱非毬麵擬和以及雙二次麯麵擬閤下的角膜麵型參數.結果 採用橢毬麵擬閤,8 mm直徑範圍的均方根值低達(2.14±0.56) μm;擬閤的穩定性好,標準偏差隻有0.56 μm;而其他擬閤方式均遠低于以上的擬閤精度.橢毬麵擬閤時,角膜前錶麵麯率半徑的平均值為(7.67±0.23)ram,相應的屈光度為(49.02± 1.44)D;角膜前錶麵的非毬麵繫數(Q值)的平均值為-0.33±0.09;其他擬閤方式下得到的麯率半徑均比橢毬麵擬和的大(P＜0.01),而角膜前錶麵Q值的絕對值小于橢毬麵擬和下的Q值(P＜0.01).結論 角膜的實際屈光度較目前的公認值48 D大,而角膜的實際麵型也更為扁長.
목적 채용타구면각막전표면면형연구중국인각막적실제면형삼수.방법 실험연구.선취40례(80안)굴광수술전검사환자,용Levenberg-Marquardt방법대측량득도적각막고도수거진행의합,연후재통과좌표변환,득출각막적삼수.령외,채용t검험비교료구면의합、선전대칭비구면의화이급쌍이차곡면의합하적각막면형삼수.결과 채용타구면의합,8 mm직경범위적균방근치저체(2.14±0.56) μm;의합적은정성호,표준편차지유0.56 μm;이기타의합방식균원저우이상적의합정도.타구면의합시,각막전표면곡솔반경적평균치위(7.67±0.23)ram,상응적굴광도위(49.02± 1.44)D;각막전표면적비구면계수(Q치)적평균치위-0.33±0.09;기타의합방식하득도적곡솔반경균비타구면의화적대(P＜0.01),이각막전표면Q치적절대치소우타구면의화하적Q치(P＜0.01).결론 각막적실제굴광도교목전적공인치48 D대,이각막적실제면형야경위편장.
Objective To study the parameters of the anterior corneal surface in Chinese eyes based on the collection of raw elevation data of the surface using the ellipsoid fitting method.Methods Eighty eyes were included in this experimental study.The Levenbery-Marquardt method was used to fit the elevation data.The parameters of the anterior corneal surface were obtained by coordinate transformation and rotation processing.Spherical fitting,conic fitting and biconic fitting were also used to obtain the parameters of the anterior corneal surface for t test comparisons.Results The root mean square fitting error with ellipsoid fitting was as low as 2.14±0.56 μm for an 8 mm fitting diameter,and the standard deviation was only 0.56 μm,showing good reliability.However,the fitting error and fitting reliability for other fitting methods were inferior to ellipsoid fitting.For ellipsoid fitting,the radius of the anterior corneal surface was 7.67±0.23 mm,and the corresponding refractive power of the anterior corneal surface was 49.02±1.44 D.The Q-value of the anterior corneal surface was-0.33±0.09.The refractive power obtained with other fitting methods was higher than the refractive power obtained from the ellipsoid fitting (P＜0.01) whereas the absolute obtained Q-value was lower than that obtained from the ellipsoid fitting (P＜0.01).Conclusion This study shows that the actual anterior corneal refractive power is higher than the widely accepted anterior corneal refractive power of 48 D and the anterior corneal surface is more prolate than expected.
