Accommodation demand and deprivation in kitten ocular development

The effects of accommodation demand and deprivation on the development of ocular optics was investigated in four groups of kittens (total n = 29). Group 1 consisted of five normal kittens; group 2 (nine kittens) had monocular radial keratotomy to induce relative hypermetropia and more accommodation demand as well as to impart interocular refractive differences (anisometropia); group 3 (eight kittens) received daily monocular atropine; and group 4 (seven kittens) had binocular radial keratotomy combined with daily monocular atropine. Regular examination provided documentation of ocular development from the first through the sixth months of life. Subsequently, the focal lengths of the crystalline lenses were determined in vitro. An apparent tendency for kitten eye pairs to grow toward isometropia, even when anisometropia had been induced early in life, was seen in those eyes in which the accommodative mechanism had been left intact (groups 1 and 2), but without accommodation anisometropia resulted (groups 3 and 4). There was relatively more elongation of the globe (3.08 +/- 0.22%) as well as shorter than normal focal lengths of the crystalline lens (-4.91 +/- 1.62% anterior, -2.78 +/- 1.54% posterior) in the eyes of the second group, and the eye pairs regained isometropia. In those eyes of the third and fourth groups that received atropine daily, there was relatively less elongation of the globe (-3.09 +/- 0.59% and -3.22 +/- 0.67%, respectively) and shorter crystalline lens focal lengths (-3.50 +/- 1.18% and -4.62 +/- 1.07% anterior, -2.64 +/- 1.02% and -1.59 +/- 0.62% posterior, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)