Infra‐Red Transmission Limits for Sunglasses

Abstract

A survey of literature relating to effects of infra‐red radiation on the eye is presented. Infra‐red radiation can be a causative agent in the production of chorioretinal lesions, and is, by itself, probably responsible for a type of visual discomfort. It is proposed that all sunglass lenses should comply with the requirement that the mean of the transmittances for 700 to 1300 nm in steps of 100 nm should be less than the respective luminous transmission factor for Illuminant C. There does not appear to be any reason for limiting the transmission of sunglass lenses for wavelengths greater than 1300 nm. Plastics lenses at present do not comply with the proposed requirement, but suitable glass lenses are commercially available.