Abstract
Abstract: :
Purpose: To evaluate the equivalence of ocular aberrations measured with a natural pupil to those measured with a dilated pupil. Methods: A VISX Wavescan was used to measure the ocular wavefront aberrations of 7 young normal subjects (Age = 26 ± 5 years, SE = -3.75 ± 3.75 D, Cyl = -0.5 ± 0.75 D). Three consecutive measurements were preformed before and after dilation on each subject. Pupil size (6mm) and defocus compensation were kept constant during the comparison. Aberrations were described by a Zernike polynomial expansion of the 6th order. T-tests were used to identify significant differences (P < 0.05) in aberrations between natural and dilated conditions. Results: After dilation, six of the subjects showed a significant decrease in defocus. Four subjects showed a significant change in the size of their coma. Two of these four subjects displayed a change in their coma’s orientation. There were no significant changes found in the 4th, 5th and 6th order aberrations. Significant changes in the high-order RMS were found in only two subjects. Conclusion: Significant, subject dependent differences were found between the wavefront aberrations measured with natural and dilated pupils. This suggests that, for some patients, aberrations measured with dilated pupils might not be applicable to vision in natural conditions.
Keywords: 519 physiological optics • 534 pupil • 500 optical properties