Buehren Tobias, Collins Michael J, Carney Leo
Contact Lens and Visual Optics Laboratory, Centre for Eye Research, School of Optometry, Kelvin Grove, Queensland University of Technology, Brisbane, Australia.
Optom Vis Sci. 2003 Feb;80(2):159-66. doi: 10.1097/00006324-200302000-00012.
To investigate the effects of eyelid pressure on corneal shape and corneal aberrations during reading.
Twenty young subjects with normal ocular health were recruited for the study. The experiment was conducted early in the morning, with subjects instructed not to perform any prolonged reading before the experiment. Corneal topography of one eye was measured with a videokeratoscope before reading and then again after a 60-min reading task. The natural position of the eyelids was photographed in primary gaze and during the reading task.
Twelve of the 20 corneas showed significant changes in central topography immediately after reading. The location of the changes corresponded closely to the position and angle of the subject's eyelids during reading. The change in shape was best described as a wave-like distortion that significantly altered some corneal wavefront Zernike coefficients. There was a significant correlation between the changes in primary vertical coma and trefoil (along 30 degrees). Within the central 6 mm of the cornea, there were significant changes in the root mean square error, overall refractive power, and astigmatism.
The changes we observed in corneal topography appear to be directly related to the force exerted by the eyelids during reading. Because the cornea is the major light-refracting surface of the eye, the optical characteristics of some eyes can be significantly changed during reading by the force of the eyelids. These findings may have important implications for the definition of refractive status and may also aid in the understanding of the relationship between reading and the development of refractive errors.
研究阅读过程中眼睑压力对角膜形状和角膜像差的影响。
招募20名眼部健康正常的年轻受试者参与本研究。实验于清晨进行，要求受试者在实验前不要进行任何长时间阅读。在阅读前用角膜地形图仪测量一只眼睛的角膜地形图，然后在60分钟阅读任务后再次测量。在第一眼位和阅读任务期间拍摄眼睑的自然位置。
20只角膜中有12只在阅读后立即出现中央地形图的显著变化。变化的位置与受试者阅读时眼睑的位置和角度密切对应。形状变化最好描述为一种波状畸变，它显著改变了一些角膜波前泽尼克系数。初级垂直彗差和三叶草像差（沿30度）的变化之间存在显著相关性。在角膜中央6毫米范围内，均方根误差、总屈光力和散光有显著变化。
我们在角膜地形图中观察到的变化似乎与阅读时眼睑施加的力直接相关。由于角膜是眼睛的主要屈光表面，阅读时眼睑的力可能会显著改变一些眼睛的光学特性。这些发现可能对屈光状态的定义具有重要意义，也可能有助于理解阅读与屈光不正发展之间的关系。
