Abstract
Corneal accommodation accounts ~9 D of accommodation in pigeon eyes and for ~8 D of the full 15–17 D accommodative range in chicken eyes.1 The mechanisms of corneal accommodation are largely unknown. To test the role of intraocular pressure changes in corneal accommodation in chick and pigeon eyes we regulated the pressure behind excised corneas and measured the changes in corneal curvature. Curvatures of excised corneas with a hydrostatic pressure applied behind them were measured using IR keratometry. The radii of curvature of the excised corneas under hydrostatic pressure were similar to those measured in the living bird and in the intact excised eyes (six chick eyes 4.34–4.63 mm and four pigeon eyes 3.55–4.07 mm). Pressure changes regulated around physiological values2 (10–22 mmHG) resulted in small changes in corneal curvature (chicks 0.14–0.33 mm and pigeons 0.10–0.16 mm). When expressed as corneal refracting power (chicks 2.50–5.69 D and pigeons 2.36–3.20 D) the changes are insufficient to account for the full range of corneal accommodation.
© 1991 Optical Society of America
PDF ArticleMore Like This
Frank Schaeffel, Virginia Romano, Tom Yau, and Howard C. Howland
MR33 OSA Annual Meeting (FIO) 1988
Jacob G. Sivak, Elizabeth L. Irving, Margot E. Andison, and Murchinson Callender
TuY1 OSA Annual Meeting (FIO) 1991
Howard C. Howland and Richard Rand
TuWW1 OSA Annual Meeting (FIO) 1991