A Study of the Comparative Effects of Ionizing Radiation and Aging on the Mammalian Lens of the Eye

Abstract

The eyes of 120 rabbits, 8–12 weeks of age, received radiation exposures of 0, 200, 600, 1000 R from a 1 MeV X-ray machine. The X-ray exposure was delivered either to the whole eye (16 mm diam. beam) or to a portion of the eye (3 mm diam. beam). All animals received a biomicroscopic examination before irradiation and at 6 month intervals thereafter until death or sacrifice intervened. A colony of 120 rabbits was divided into six groups according to a balanced incomplete block arrangement designed statistically for maximum information. Animals were sacrificed, four at a time, at 6 month intervals until each of the six groups was depleted. The relationship between ionizing radiation exposure and aging is assessed in terms of physical data involving the mass, density, hardness and light transmission of the rabbit lens, and in terms of clinical observations. These data indicate that changes in the physical properties of the lens are more affected by aging than by radiation, whereas, the reverse is true for clinical changes as observed biomicroscopically. In general, these data lend support to the hypothesis that there may be a relationship between radiation damage and aging in the rabbit lens.