Magnitude and orientation of zernike terms in patients with keratoconus
Magnitude and orientation of zernike terms in patients with keratoconus
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DOI：
10.1167/iovs.06-1285
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发表时间：
2007-07-01
影响因子：
4.4
通讯作者：
Tano, Yasuo
中科院分区：
文献类型：
--
作者：
Kosaki, Ryo;Maeda, Naoyuki;Tano, Yasuo
目的.测量圆锥角膜患者配戴和不配戴硬性透气性角膜接触镜时Zernike项的大小和方向。对76只圆锥角膜、58只可疑圆锥角膜和105只正常眼进行了研究。为了确定RGP镜片的效果，对19只圆锥角膜患者、9只疑似圆锥角膜患者和17只正常人进行了比较。用波前传感器测量4 mm瞳孔的高阶像差（HOA），并通过矢量分析计算三叶草的大小、轴向和彗差。Zernike矢量分析显示，圆锥角膜或疑似圆锥角膜患者的垂直昏迷明显，下慢模式，平均轴分别为82.5或91.0。圆锥角膜和可疑圆锥角膜的三叶形轴平均值（93.8）与正常眼（35.4）不同，圆锥角膜呈倒三叶形。尽管使用RGP透镜的总HOA显著降低（圆锥角膜和可疑圆锥角膜，分别为P <0.001和P = 0.012），但使用该透镜后，彗差和三叶形轴的模式发生了逆转。圆锥角膜患者除了具有较大量的三叶形、彗差、四叶形和继发性散光外，与正常眼相比，还具有反向彗差和反向三叶形像差。虽然RGP镜片矫正了不规则散光，但由于残留的垂直彗差，相反方向上的较小彗星状视网膜图像仍然存在。
PURPOSE. To measure the magnitude and orientation of the Zernike terms in keratoconic eyes, with and without rigid gas-permeable (RGP) contact lenses.METHODS. A total of 76 eyes with keratoconus, 58 eyes with keratoconus suspect, and 105 normal eyes were studied. To determine the effect of RGP lenses, 19 eyes with keratoconus, 9 eyes with keratoconus suspect, and 17 normal eyes, with and without an RGP lenses, were compared. Ocular higher-order aberrations (HOAs) were measured with a wavefront sensor for a 4-mm-diameter pupil, and the magnitudes, axes of trefoil, and coma were calculated by vector analysis.RESULTS. Zernike vector analysis showed prominent vertical coma with an inferior slow pattern, with mean axes of 82.5 or 91.0 in the patients with keratoconus or keratoconus suspect, respectively. The mean axes of trefoil in patients with keratoconus (93.8) and keratoconus suspect (100.6) differed from that in normal subjects (35.4), indicating that keratoconus has a reverse trefoil pattern from that of normal eyes. Although the total HOAs were significantly ( keratoconus and keratoconus suspect, P < 0.001 and P = 0.012, respectively) reduced with an RGP lens, the patterns of the axes of coma and trefoil were reversed with the lens.CONCLUSIONS. In addition to the larger amount of trefoil, coma, tetrafoil, and secondary astigmatism, keratoconic eyes tend to have a reverse coma pattern and reverse trefoil aberrations compared with normal eyes. Although RGP lenses correct the irregular astigmatism, smaller comet-like retinal images in the opposite direction remain due to residual vertical coma.