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K.R. Huxlin, G. Yoon, L. Nagy, E. Brandon, J. Porter, I. Cox, S. MacRae, D. Williams; Ocular Wavefront Aberrations in Awake Cats . Invest. Ophthalmol. Vis. Sci. 2003;44(13):996.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Measurement of wavefront aberrations in human eyes has become the most reliable, quantitative way of assessing the optical impact of ocular manipulations. Wavefront measures have also been performed in several other species, but never in cats, an animal model of choice for ocular studies Our goal was to measure wavefront aberrations reliably in live, awake-behaving cats. Methods: Cranial head-posts and subconjunctival eye coils were implanted into 6 normal, adult cats to enable precise monitoring of their eye movements. Standard psychophysical methods were used to train the cats to fixate small visual targets on a computer monitor. A compact, Shack-Hartmann wavefront sensor was placed between the animal and computer monitor and aligned with the cat's visual axis during fixation. Wavefront images were collected and aberrations were measured over a 6mm pupil, up to 5th order Zernike polynomials (18 Zernike modes). Average wave aberrations were calculated for each eye from at least three sessions, each on a different day, with twelve to fifteen wavefront measurements collected per session. Results: Data obtained from different sessions exhibited high repeatability for the same eyes. For the 8 eyes studied, 5 were hyperopic and 3, myopic. In general, the ocular aberrations of cat and human eyes were similar. Second order Zernike modes (defocus and astigmatism) accounted for 92.5% of the wave aberration's variance, while the higher order terms (3rd through 5th order) accounted for the remaining 7.5%. Unlike the normal human population, however, our sample of cat eyes showed a vertical coma (Z3-1) mean value significantly greater than zero. Conclusions: We have developed an awake, fixating cat model in which ocular wavefront aberrations can be measured reliably and repeatedly in a manner that is directly comparable to such measures in humans. Our findings suggest that cats and humans have similar amounts of defocus and astigmatism, as well as higher order aberrations. These data form a basis for future studies that use wavefront sensing to quantify the optical effects of ocular manipulations in experimental animals.
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