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Tae Moon Jeong, Geunyoung Yoon; Effect of dynamic movement of customized optics on visual benefit in abnormal eyes. Journal of Vision 2004;4(11):60. doi: https://doi.org/10.1167/4.11.60.
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© ARVO (1962-2015); The Authors (2016-present)
PURPOSE: Customized optics, especially contact lenses, move dynamically after blinks. A better understanding of how retinal image quality is changed by the dynamic movement of customized contact lens is required to demonstrate the feasibility of improving vision with customized optics. The goal of this study is to theoretically investigate the visual benefit when correcting higher order aberrations in abnormal eyes with dynamic decentration and rotation of customized optics.
METHODS: Wavefront aberrations for fifteen abnormal (keratoconic) eyes were measured with a large dynamic range Shack-Hartmann wavefront sensor. From measured wavefront aberrations, modulation transfer function under the white light condition was calculated to investigate visual benefit. Visual benefit was defined as the ratio of the volume under the modulation transfer functions (vMTF) with second and higher order correction to that with second order optimization only. These visual benefits were calculated with dynamic decentration and rotation of customized optics. The visual benefit assuming the perfect higher order correction was also calculated for the comparison. To simulate this dynamic movement, Monte-Carlo method was used to generate decentration and rotation of customized optics weighted by Gaussian distribution.
RESULTS: When perfectly correcting higher order aberrations with customized optics, abnormal eyes experienced the visual benefit of 4.4 ± 2.0 for a 6 mm pupil size. This visual benefit is 2 times higher than that of normal eyes. Decentration and rotation were significant factors contributing to the decrease of visual benefit. When considering the dynamic movement of customized optics, abnormal eyes experienced the visual benefit of 1.5 ± 0.2 with the standard deviations of 300 _m decentration and 7 degree rotation in Gaussian distribution. On the other hand, normal eyes experienced 1.3 ± 0.1 with the same standard deviations for decentration and rotation.
CONCLUSIONS: Correcting higher order aberrations in abnormal eyes provides larger visual benefit than in normal eyes. However, visual benefit for abnormal eye is more sensitive to decentration and rotation of customized optics compared to the normal eyes. Although the question about actual perception of patient's vision remains, our calculation shows that correcting higher order aberration with customized optics improves retinal image quality even with the dynamic movement of customized optics.
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