When the solar eclipse occurred in August 2017, millions of Americans immediately turned to online retailers to purchase “eclipse viewing sunglasses.” However, it quickly became clear that many manufacturers sold counterfeit sunglasses that offered no real protection from the sun’s ultraviolet rays. While the vast majority of Americans kept their eyesight protected with verified eclipse viewing glasses, some individuals suffered permanent damage from looking directly at the sun.

This got many people asking a similar question: Why exactly does the sun’s ultraviolet light cause eye injury?

What is Ultraviolet Light?

Ultraviolet light is one of several types of radiation given off by the sun. There are three types of ultraviolet light, but only two reach earth. These are ultraviolet A and ultraviolet B. UVA has a wavelength of 340 to 400 nanometers and is famous for causing sunburn. UVB has a wavelength of 320 to 340 nm and causes not only sunburn but ages the skin. This type of radiation doesn’t travel as far or penetrate the body as deeply as UVA, and it can be blocked by UV protective clothing, sunscreen, cloud cover, and even glass. It is still important to block both types of UV radiation when choosing protective eyewear.

How Does Ultraviolet Light Damage the Eyes?

UV light damages the eyes much the same way it damages the skin. It can “cook” the cells in the eyes and damage their molecular structure and their DNA. They also peroxidize protective lipids in the eye by stimulating the production of free radical molecules, which then injure cells.

Exposing the eyes to UV light for a long time leads to several injuries, some of which may require medical care. These can include:

• Snow blindness: This is a hazard for skiers, people who hike high in the mountains and people who spend long hours on a boat or on white sand beaches in the summer. It is basically a sunburn on the surface of a person’s eye. Though it can be painful, snow blindness is usually benign, and the person’s vision goes back to normal after a while.
• Cataracts: A small but significant percentage of cataracts are the result of exposure to UV light, especially UVB light. Cataracts occur when the lens of the eye becomes clouded. Luckily, it’s possible for an eye surgeon to fix cataracts through a surgical procedure.
• Pterygium: This is a pink membrane that forms over the conjunctiva, which is the clear mucous membrane over the front of the eye. Also called surfer’s eye, pterygia are benign but unsightly and can feel like grit in the eye.
• Macular Degeneration: This is degeneration of the macula, the very center of the retina. Though macular degeneration is most often an age-related problem, exposure to UV light can exacerbate it.
• Eye Cancer: Most cancers of the eye actually happen on the eyelid, but malignancies can occur in the eye itself. These are sometimes melanomas, the most dangerous forms of skin cancer.

How to Prevent UV Damage

The best way to prevent UV damage to the eyes is to wear protective glasses. You certainly don’t need to wear eclipse sunglasses year-round, but a good pair of protective glasses blocks all or nearly all of the ultraviolet light and even blocks the majority of visible light. For more information about how to protect your eyes from UV rays, don’t hesitate to speak to your local eye Newport Beach Eye Surgeon or eye doctor.

Thanks to our friends and contributors from Retina Associates of Orange County for their insight into eye damage.