Contact lens dosimetry of solar ultraviolet radiation

Background : Ultraviolet radiation from the sun has been implicated in the pathogenesis of many ocular conditions. However, the amount of UV reaching the eye is not well defined. Methods : A contact lens made from the UV-sensitive plastic polysulphone was used to measure the dose of UV radiation at the surface of the eye for two subjects over six wearing trials. Results : The average ratio of UV radiation exposure at the surface of the eye to that of the UV radiation in the surrounding environment (ambient dose) was found to be 28 ± 9 per cent. The temporal UV dose appeared lower than both the central and nasal UV doses in five of the six wearing trials but these differences did not reach statistical significance. Conclusions : Contact lenses made from polysulphone can be used to estimate the regional dose of solar ultraviolet radiation. (Clin Exp Optom 1997; 80: 6: 204–210)