Visual Neuroscience

Short Communication

Developing eyes that lack accommodation grow to compensate for imposed defocus

Frank Schaeffela1, David Troiloa2, Josh Wallmana2 and Howard C. Howlanda1

a1 Section of Neurobiology and Behavior, Cornell University, Ithaca, New York

a2 Department of Biology, City College of The City University of New York, New York


The eyes of growing chicks adjust to correct for myopia (eye relatively long for the focal length of its optics) or hyperopia (eye relatively short for the focal length of its optics). Eyes made functionally hyperopic with negative spectacle lenses become myopic and long, whereas eyes made functionally myopic with positive spectacle lenses become hyperopic and short. We report here that these compensatory growth adjustments occur not only in normal eyes but also in eyes unable to accommodate (focus) because of lesions to the Edinger-Westphal nuclei. Thus, at least in chicks, accommodation is not necessary for growth that reduces refractive errors during development, and may not be necessary for the normal control of eye growth.

(Received November 07 1988)

(Accepted November 15 1989)


p1 Present address of Frank Schaeffel: Dept. of Experimental Ophthalmology, University Eye Hospital, Berghof Ob Dem Himmelreich 9, D-7400, Tuebingen, W. Germany

p2 Present address of David Troilo: University Laboratory of Physiology, Parks Road, Oxford OXI 3PT, England

p3 Biology Dept., City College, CUNY, New York, NY 10031