Quantitative analysis of higher-order wavefront aberration and irregular astigmatism and assessment of their influence on visual function

探讨了定量分析角膜前表面及全眼结构产生的高阶像差和不规则散光的方法。利用傅里叶级数谐波分析对角膜成像数据进行分解，将不规则散光（不对称分量和高阶不规则分量）从规则散光中分离出来。该方法应用于各种眼部疾病和眼科外科手术。我们用傅立叶分析法对影像摄影资料进行连续分析，定量评估圆锥角膜的纵向进展。在光屈光性角膜切除术后，不规则散光成分的增加与对比敏感度的下降显著相关。将波前数据展开为泽尼克系数，量化了眼高阶像差。用三阶系数的均方根来描述彗形像差，用四阶系数的均方根来描述球状像差。我们发现白内障患者的总高阶像差明显增加，而且核性白内障和皮质性白内障的像差模式有明显差异。在假晶状眼中，测量视调节量，评估角膜多焦性和角膜像差。结果表明，视调节量与角膜多焦性有显著相关。我们还发现角膜彗差与视调节显著相关，而角膜球差与视调节无关。对PSF和MTF的计算机模拟表明，在没有高阶像差的眼睛中，0.5屈光度的焦移对视网膜图像的恶化程度明显高于有中度彗差的眼睛。利用傅里叶分析方法，定义了角膜不规则散光指数（不对称和高阶不规则）的正常范围。术后眼病理及术后情况用正常范围Less进行评估

We investigated the methods to quantitatively analyze higher-order aberrations and irregular astigmatism which arise from the anterior surface of the cornea as well as whole eye structure. The videokeratography data of the cornea were decomposed using Fourier series harmonic analysis, and irregular astigmatism (asymmetry component and higher-order irregularity) were separated from the regular form of astigmatism. This method was applied for various ocular diseases and ophthalmic surgical procedures. We quantitatively evaluated the longitudinal progression of keratoconus by serially analyze videokeratography data with Fourier analysis. In eyes after photorefractive keratectomy, increases in irregular astigmatism component were significantly correlated with deterioration of contrast sensitivity. Higher-order aberration of the eye was quantified by expanding the wavefront data into Zernike coefficients. Root-mean-square of third order coefficients was used to describe coma-like aberration … More , and root-mean-square of fourth order coefficients was used to denote spherical-like aberration, We found that total higher-order aberrations were significantly increased in eyes with cataract, and that the pattern of aberrations was markedly different between eyes with nuclear cataract and cortical cataract. In pseudophakic eyes, amount of apparent accommodation was measured, and corneal multifocality and corneal aberration were assessed. It was indicated that the mount of apparent accommodation was significantly correlated with the amount of corneal multifocality. We also found that corneal coma aberration was significantly correlated with apparent accommodation, but corneal spherical aberration was not. Computer simulation of PSF and MTF demonstrated that a focus shift of 0.5 diopter deteriorated the retinal image significantly more in eyes without higher-order aberrations than in eyes with a moderate amount of coma-like aberrations. Using Fourier analysis of videokeratography data, the normal range was defined for the cornea irregular astigmatism index (asymmetry and higher order irregularity). Eyes with ocular pathologic and postsurgical conditions were evaluated using the normal range Less