Freshly isolated rabbit lenses were incubated in anosmolar culture media to study the effects of osmotic shock on lens transparency and protein synthesis. The rate of protein synthesis was measured using three markers, namely alpha-crystallin, a water soluble protein, vimentin, a cytoskeletal protein and MP-26, an intrinsic membrane protein. It was found that only when lenses were cultured in a hyperosmolar medium of 450 mOsM, was there a significant decrease in the rate of lens protein synthesis. The hyperosmolar medium inhibited the synthesis of all three marker proteins. Lens clarity also depended on the solute used to prepare the hyperosmolar medium. Our experimental data showed that there is no relation between decreased protein synthesis and the appearance of lens opacity in the organ cultured rabbit lens.