To the Editor.
—Taylor et al1 report that visible light, particularly blue light (400 to 500 nm), may be a risk factor for age-related macular degeneration (ARMD) based on possible photo-oxidative stress, although no equivalent risk was found for UV-B (290 to 320 nm) or UV-A (320 to 400 nm) exposure. May I suggest that two variables explicitly excluded from this study may affect such risk, particularly in combination? One is "indoor exposure,"1 which I take to mean artificial light. Indoor and outdoor ambient illumination intensity levels derived from such sources as the ubiquitous fluorescent or mercury-vapor streetlight are typically 1.5 to 3 log units (ie, 30 to 1000 times) below outdoor daylight levels, although many illuminance standards in lighting have increased in intensity by a factor of 2 to 3 from what they were a generation ago. The stared-at phosphors of television and computer displays fall in
Simons K. Artificial Light and Early-Life Exposure in Age-Related Macular Degeneration and in Cataractogenic Phototoxicity. Arch Ophthalmol. 1993;111(3):297-298. doi:10.1001/archopht.1993.01090030015002