Optical radiation safety of ophthalmic sources

The phytotoxicity of ultraviolet (UV) sources has long been recognized. Less obvious are the potential hazards to the eye from ophthalmic light sources that do not emit UV. To assess potential hazards, not only must the optical and radiometric parameters of the optical source in question be considered, but also the geometrical exposure factors. This knowledge is required to determine accurately the irradiances (dose rates) to exposed tissues. Both photochemically and thermally induced damage are possible from intense light sources used in medicine and surgery; however, thermal injury is rare unless the light source is pulsed or nearly in contact with tissue. Genetically, photochemical interaction mechanisms are most pronounced at short wavelengths (UV and bluelight) where photon energies are greatest, and will also be most readily observed for lengthy exposure durations.