Effect of infrared radiation on the lens

BACKGROUND: Infrared (IR) radiation is becoming more popular in industrial manufacturing processes and in many instruments used for diagnostic and therapeutic application to the human eye. AIM: The present study was designed to investigate the effect of IR radiation on rabbit’s crystalline lens and lens membrane. MATERIALS AND METHODS: Fifteen New Zealand rabbits were used in the present work. The rabbits were classified into three groups; one of them served as control. The other two groups were exposed to IR radiation for 5 or 10 minutes. Animals from these two irradiated groups were subdivided into two subgroups; one of them was decapitated directly after IR exposure, while the other subgroup was decapitated 1 hour post exposure. IR was delivered from a General Electric Lamp model 250R 50/10, placed 20 cm from the rabbit and aimed at each eye. The activity of Na(+)-K(+) ATPase was measured in the lens membrane. Soluble lens proteins were extracted and the following measurements were carried out: estimation of total soluble protein, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared (FTIR) spectroscopy. For comparison between multiple groups, analysis of variance was used with significance level set at P < 0.001. RESULTS: The results indicated a change in the molecular weight of different lens crystalline accompanied with changes in protein backbone structure. These changes increased for the groups exposed to IR for 10 minutes. Moreover, the activity of Na(+)-K(+) ATPase significantly decreased for all groups. CONCLUSIONS: The protein of eye lens is very sensitive to IR radiation which is hazardous and may lead to cataract.