Measurement of refractive index in an intact crystalline lens.

A knowledge of the refractive index distribution within the crystalline lens is necessary to define the optical properties of the eye. This report describes the first nondestructive method for measuring the refractive index of intact crystalline lenses based on the work of Chu (1977) [Electron Lett. 13, 736-738] and Barrell and Pask (1978) [Opt. Commun. 27, 230-234] for optical fibre preforms. The method is simpler and more accurate than previous methods and shows that the rat crystalline lens has a smooth and almost parabolic distribution of refractive index.