After going out on a boat in Portugal, CNN anchor Anderson Cooper woke up at night with a burning sensation in his eyes and found that he was blind. Like most people, he had learned as a child not to stare directly at the sun. However, also like most people, Cooper didn’t realize how dangerous the sun’s ultraviolet light can be to your eyes, and what steps need to be taken to avoid it.
Cooper is one of a growing number of people who have experienced eye damage from ultraviolet light. He was lucky; he could see again less than two days later. Ultraviolet-induced photokeratitis can persist far longer than that, and can even cause permanent damage to vision. Symptoms include tears and moisture, pain and discomfort, narrowed pupils, and eyelid twitching. Reflected sunlight can cause photokeratitis as much as direct, as can using arc welding equipment without proper eye protection.
Ultraviolet light isn’t visible to people—though it is to bees—but it still packs a punch. It’s a slightly shorter wavelength than visible light, and it comes from the sun like visible light does. In addition to photokeratitis, it can damage vision in several other ways:
- Ultraviolet light is a major cause of skin cancer, to which the thin skin of the eyelids is particularly vulnerable.
- The leading cause of blindness is clouding of the lens of the eye, or cataracts. Research shows that exposure to ultraviolet light increases the formation of cataracts.
- Age-related macular degeneration, deterioration of the center part of the retina, is another leading cause of blindness. Ultraviolet light damaging the retina is believed to be a contributing factor to this deterioration.
You can protect yourself with sunglasses—a precaution Cooper says he had failed to take—but not all shades offer the same level of protection. There’s no standard labeling, but anything that says it offers ultraviolet protection probably does offer some degree. Polarized lenses shield your eyes from glare. Make sure you have lenses big enough to offer complete protection.