Corneal aberrations and visual performance after radial keratotomy
Corneal aberrations and visual performance after radial keratotomy
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DOI：
10.3928/1081-597x-19980701-05
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发表时间：
1998-07-01
影响因子：
2.4
通讯作者：
Yee, RW
中科院分区：
文献类型：
--
作者：
Applegate, RA;Howland, HC;Yee, RW
背景：屈光手术和视频角膜摄影术使我们能够研究手术改变角膜形状引起的相对较大的角膜像差结构对视觉表现的影响。方法：我们量化了9例正常角膜切开术和23例放射状角膜切开术患者的一只眼的对数对比敏感度函数下的面积(AULCSF)和两种人工瞳孔大小(3 mm和7 mm)的角膜第一表面波前差。用正弦波光栅测6个空间频率的对比敏感度。结果：对于正常眼，随着时间的推移，波前变化不明显，对于放射状角膜切开术，存在明显的瞳孔大小依赖变化。对于3 mm的瞳孔，手术引起的角膜波前变化在7 mm时变大(约为术前值的30倍)。结论：放射状角膜切开术与准分子激光屈光性角膜切削术一样，使像差的分布由三级显性(昏迷样像差)变为四级显性(球面状像差)。放射状角膜切开术引起的像差和对比敏感度的损失随着透明区直径的增加而减少。放射状角膜切开术会导致眼睛光学像差的增加，而大瞳孔(7 Mm)而不是小瞳孔(3 Mm)的增加与对比敏感度的降低有关。
BACKGROUND: Refractive surgery and videokeratography have allowed us to study the effects on visual performance of relatively large changes in corneal aberration structure induced by surgical changes in corneal shape.METHODS: We quantified in one eye of nine normal and 23 radial keratotomy patients, the area under the log contrast sensitivity function (AULCSF) and corneal first surface wavefront variance for two artificial pupil sizes (3 and 7 mm). Contrast sensitivity was measured with sine-wave gratings at six spacial frequencies. Wavefront variance was derived from videokeratographs using Zernike polynomials.RESULTS: For normals eyes there were no significant changes over time, For eyes that had radial keratotomy, there were significant pupil size-dependent changes. For the 3 mm pupil, there were significant surgery-induced changes in the corneal wavefront variance which became large (approximately 30 times preoperative values) at 7 mm. Significant correlated changes in AULCSF for the 7 mm pupil but not for the 3 mm pupil occurred immediately following surgery and remained.CONCLUSIONS: Radial keratotomy, like photorefractive keratectomy, shifts the distribution of aberrations from third order dominance (coma-Iike aberrations) to fourth order dominance (spherical-like aberrations). Radial keratotomy-induced aberrations and loss in contrast sensitivity are reduced with increasing clear zone diameter. Radial keratotomy induces an increase in the optical aberrations of the eye and the increase for large pupils (7 mm) but not small (3 mm) is correlated to a decrease in contrast sensitivity.