MEASUREMENT OF ULTRAVIOLET-RADIATION AT THE SURFACE OF THE EYE

Purpose. A new method for the measurement of ultraviolet radiation tha t reaches the surface of the eye is described. Methods. The technique uses contact lenses produced from the ultraviolet-sensitive plastic po lysulfone. Two types of polysulfone contact lenses (9 mm and 12 mm in diameter) were manufactured from a polysulfone rod. The 9-mm polysulfo ne contact lens could be calibrated and used to determine the ocular-t o-ambient exposure ratio in a fashion similar to polysulfone film badg es. The 12-mm polysulfone contact lens was designed as a ''piggy-back' ' lens and required a larger diameter polymethylmethacrylate carrier l ens to fit the eye adequately. A method of in vivo stabilization was d eveloped to minimize lens rotation. Results. During four wearing trial s, the ratio of ocular-to-ambient ultraviolet exposure ranged from 4% to 23%. Conclusions. Contact lenses manufactured from polysulfone offe r the potential to study the exposure of the eye to ultraviolet radiat ion. 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.