Optical Properties of the Bovine Lens Before, During and After the Induction of Cold Cataract

Abstract

Introduction The induction of cataracts by reducing temperature has proven to be an attractive experimental paradigm for scientists involved in in vitro cataract research because of the speed and simplicity of the method and because cold cataracts are usually reversible (Bon, 1959; Zigman and Lerman, 1964; Lerman and Zigman, 1967). In general, cold cataracts can be induced in mammalian lenses by cooling to temperatures below 10°C but above freezing (Lerman and Zigman, 1967; Siezen et al., 1985; Uga et al., 1986). Age and species differences in the development of cold cataract have led to efforts to identify the responsible protein (Lerman and Zigman, 1967). However, uncertainty exists as to whether cold cataracts are due to a specific lens protein or to disruption of supramolecular protein organization (Lowenstein and Bettelheim, 1979; Ondruska and Hanson, 1983). The principle function of the lens is to focus or assist the cornea to focus light on the retina. While changes in lens transparency in vitro have been measured photometrically (Dragomirescu et al., 1983) little attention has been paid to lens refraction function in in vitro cataract research. We have developed a computer operated scanning laser system capable of measuring subtle changes in lens focal length and transmittance during long-term organ culture (Sivak et al., 1986). This method has been used to monitor lens damage produced by a variety of chemical agents as well as UV-B radiation (Sivak et al., 1990, 1991; Stuart et al., 1990). This study represents an effort to use the laser scanning system to measure bovine lens focal and relative transmittance characteristics before, during and after cold cataractogenesis.