Refractive index contours in the human lens.

The refractive index values along the equatorial and sagittal planes of lenses of varying ages were measured using a reflectometric fibre optic sensor. In younger lenses (from the third decade) and in one older lens, the index profiles from the two planes did not concur when plotted on a normalized scale refuting, in these lenses, the assumption of concentric, isoindicial contours which follow the shape of the lens. Agreement between the normalized profiles did occur with all other lenses investigated (aged 47 and older).