Is the increasing exposure of the eye to near‐infrared radiation from remote controls and sensing a threat to the lens?

Summary The current safety guideline for near infrared radiation (IRR) exposure in the crystalline lens is based on thermal damage. However, two previous findings implied that there may be a cumulative photochemical effect. The present study aims to investigate if near IRR induces cumulative lens damage considering irradiance exposure time reciprocity. Before exposure, 6‐weeks‐old albino rats were anesthetized and the pupils of both eyes were dilated. Five minutes after pupil dilation, the animals were unilaterally exposed to 1,090 nm IRR within the pupil area. Temperature was recorded with thermocouples placed in the selected positions of the eye. At the planned post‐exposure time, the animal was sacrificed and the lenses were extracted for measurements of forward light scattering and macroscopic imaging. The findings that an in vivo 8 sec exposure to near IRR at 1090 nm within the pupil resulting in a temperature rise of 10°C at the anterior segment of the rat eye induced cataract with a time delay and no cumulative lens damage occurred after long term exposure to 1,090 nm IRR, indicates that IRR at 1,090 nm produces thermal cataract, probably by indirect heat conduction from absorption in tissues surrounding the lens.