Many subjects reflect UV radiation, in varying amounts, but the human eye is incapable of seeing wavelengths shorter than around 400nm due to the protein absorption of the eye’s crystalline lens. Some people lack lenses in their eyes, either due to accidental damage, disease or more rarely, a birth defect. This condition, known as aphakia, allows these people to see UV wavelengths, demonstrated by illuminating an optometrist’s chart with just 365nm radiation. Most people with aphakia need to wear thick glasses to focus, however, and these absorb most of the reflected UV radiation. There are also numerous reports of people who have had cataract surgery being able to perceive UV radiation.
Get Digital Ultraviolet and Infrared Photography now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
