Measurement of ultraviolet radiation at the surface of the eye.

PURPOSE A new method for the measurement of ultraviolet radiation that reaches the surface of the eye is described. METHODS The technique uses contact lenses produced from the ultraviolet-sensitive plastic polysulfone. Two types of polysulfone contact lenses (9 mm and 12 mm in diameter) were manufactured from a polysulfone rod. The 9-mm polysulfone contact lens could be calibrated and used to determine the ocular-to-ambient exposure ratio in a fashion similar to polysulfone film badges. The 12-mm polysulfone contact lens was designed as a "piggy-back" lens and required a larger diameter polymethlylmethacrylate carrier lens to fit the eye adequately. A method of in vivo stabilization was developed to minimize lens rotation. RESULTS During four wearing trials, the ratio of ocular-to-ambient ultraviolet exposure ranged from 4% to 23%. CONCLUSIONS Contact lenses manufactured from polysulfone offer the potential to study the exposure of the eye to ultraviolet radiation. The smaller diameter lens can measure an average ocular exposure, whereas the larger, stabilized, piggy-back design may allow regional dose assessment across the entire lens surface.