Photoacoustic, Fluorescence and Light Transmission Spectra of Normal, Aging and Cataractous Lenses

Photoacoustic spectroscopy (PAS) reveals the presence of a 340–360 nm absorption band in the normal lens which increases in magnitude with age and is particularly pronounced in the brown nuclear cataract. The cortical cataracts showed low fluorescence and PAS absorption while the mixed cataracts showed intermediate levels of fluorescence intensity and PAS absorption. These data provide further evidence that the age-related accumulation of fluorescent pigments is responsible for the increasing yellow color of the lens nucleus and the corresponding decrease in UV and visible transmission. The brown nuclear cataract appears to be an extreme example of such a process. The development of anterior cortical opacification prevents further photochemical generation of the fluorescent pigments and the corresponding PAS absorption band.