Are all aberrations equal?
Are all aberrations equal?
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DOI：
10.3928/1081-597x-20020901-12
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发表时间：
2002-09
影响因子：
2.4
通讯作者：
R. Applegate;E. Sarver;V. Khemsara
中科院分区：
文献类型：
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作者：
R. Applegate;E. Sarver;V. Khemsara
目的确定固定RMS误差（25 μ m，6 mm瞳孔）下标准化Zernike多项式（第二至第四径向阶）的每种模式如何影响高对比度和低对比度logMAR视力。方法3名健康志愿者作为研究对象。CTView用于生成光学畸变logMAR图表。调节功能瘫痪，瞳孔放大。将眼睛的中央凹消色差轴与3 mm瞳孔对齐，并使眼睛达到最佳屈光。阅读像差视力表，直到遗漏5个字母。将每个受试者的数据标准化为通过阅读无畸变图表获得的敏锐度，并绘制为作为Zernike模式函数的字母丢失。结果离焦（Z2（0））对字母视敏度的影响大于散光（Z2（2），Z2（-2））。昏迷组（Z3（1），Z3（-1））视力下降较三叶组（Z3（3），Z3（-3））明显。球面像差（Z4（0））和次级散光（Z2（2）、Z4（-2））对视力的影响远大于四叶像差（Z4（4）、Z4（-4））。结论1.对于等量的RMS误差，并非Zernike多项式的所有系数在高对比度和低对比度logMAR敏锐度中引起等同的损失。2.集中在金字塔中心附近的波前误差比金字塔边缘附近的模式对视力的影响更大。3.图表外观的巨大变化并没有反映在视觉表现的同样大的下降（即，受试者可以正确识别高度畸变的字母）。4.模式之间的相互作用使加权每个Zernike模式以获得视觉效果变得复杂。
PURPOSE To determine for a fixed RMS error (25 microm, over a 6-mm pupil) how each mode of the normalized Zernike polynomial (second through the fourth radial order) affects high and low contrast logMAR visual acuity. METHODS Three healthy volunteers served as subjects. CTView was used to generate optically aberrated logMAR charts. Accommodation was paralyzed and pupils dilated. The foveal achromatic axis of the eye was aligned to a 3-mm pupil and the eye was optimally refracted. Aberrated acuity charts were read until five letters were missed. Data were normalized for each subject to the acuity obtained by reading unaberrated charts and plotted as letters lost as a function of Zernike mode. RESULTS Defocus (Z2(0)) decreased letter acuity more than astigmatism (Z2(2), Z2(-2)). Coma (Z3(1), Z3(-1)) decreased acuity more than trefoil (Z3(3), Z3(-3)). Spherical aberration (Z4(0)) and secondary astigmatism (Z2(2), Z4(-2)) decreased acuity much more than quadrafoil (Z4(4), Z4(-4)). CONCLUSIONS 1. For an equal amount of RMS error not all coefficients of the Zernike polynomial induce equivalent losses in high and low contrast logMAR acuity. 2. Wavefront error concentrated near the center of the pyramid adversely affects visual acuity more than modes near the edge of the pyramid. 3. Large changes in chart appearance are not reflected in equally large decreases in visual performance (ie, subjects could correctly identify highly aberrated letters). 4. Interactions between modes complicate weighting each Zernike mode for visual impact.