Light scattering in lens research: an essay on accomplishments and promises.

This paper briefly reviews light scattering methodologies in lens research. In the phenomenological sense cataract formation (lens opacities or turbidities) in its early stages can be described by enhanced scattering of light. In the analytical sense information is obtained on the molecular entities involved in light scattering. In Section 2, different methodologies (mainly static and dynamic) of light scattering experiments are described, which had been used successfully in lens research. In Section 3 the problem of interpretation of light scattering data in condensed phase is considered. It is pointed out that due to interparticle interactions the concentration dependence of the data must be considered. If dilution or thin sectioning of samples is not an option, it is better to report molecular parameters in terms of diffusion coefficients or decay times. In Section 4, a case is made to encourage light scattering experiments in the polarized/depolarized modes both in static and dynamic light scatterings. Preliminary data obtained with polarized/depolarized dynamic light scattering measurements on alpha-crystallin and interpreted in view of model systems and literature data imply that the molecule is a compact sphere with somewhat restricted segment mobility. The preliminary nature of this information is due to the unavailability of high power lasers and efficient polarizers in my lab at the time of these experiments.