Purchase this article with an account.
ML Kisilak, MC W Campbell, EL Irving, JJ Hunter; Hartmann-Shack Measurements Of The Monochromatic Image Quality In The Chick Eye During Emmetropization . Invest. Ophthalmol. Vis. Sci. 2002;43(13):2924.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: In human, myopia has been associated with an increase in some aberrations but the relationship between the two is not understood. We wished to track the monochromatic image quality on the retina during normal growth and during the experimental induction of refractive error. We have designed a new Hartmann-Shack apparatus and analysed the wavefront aberrations in the developing chick eye model. Methods: On the first day post-hatching, chicks were unilaterally fitted with plus or minus 15 D goggles. The other eye acted as a control. Goggles were removed for brief periods for Hartmann-Shack wavefront measurements performed on days 0, 2, 4, 7, 10 and 14 and for retinoscopy performed on days 0, 7, 10 and 14. The apparatus was modified for the range of pupil sizes, chick movement and aberrations observed. Sensitivity was increased with a cooled CCD camera and by pixel binning. Results: Goggled eyes developed refractive errors consistent with the goggle power. The Hartmann-Shack apparatus developed is able to measure aberrations in the uncorrected eye of an unanaesthetised animal across a 2 mm diameter natural pupil, as early as the first day post-hatching. A limitation of the measurement is the assessment of the direction of gaze. Centration of the beam in the pupil was achieved by using a visible wavelength. During growth of the ungoggled eye, total root mean square (rms) wavefront error decreases along with a reduction in second order defocus terms. The Hartmann-Shack apparatus was more sensitive to astigmatism than was retinoscopy. Higher-order aberrations also decreased for a fixed pupil size. Early analysis of goggled eyes suggests that the defocus of the eye changes much more than the higher-order aberrations. Conclusion: A powerful new technique has been demonstrated for tracking the quality of retinal images in chick eyes during growth and emmetropization. Information from this study will be important to understanding the role of optical aberrations in signalling the direction of defocus.
This PDF is available to Subscribers Only