For those who spend a lot of time in the sun, you may be interested to find out your eyes and skin are most vulnerable at different times of the day. While many apps have measurements for the ultraviolet index telling us when our skin is most susceptible for damage, not as much data is available for ocular damage. 

“Why do we need a separate system for measuring UV light damage and the eye?”
Sun rays travel in waves. When the sun is highest in the sky (summer time and roughly 10:00 am to 2:00 pm) the UV index is highest, and your skin is the most sensitive to damage. At the same time, your ocular system is designed to protect you BEST at this time of day. Your brow bone covers your eyes, preventing most direct light from entering the eyes and damaging the internal structures. 

So when is the eye most vulnerable? It turns out, when the sun is lower on the horizon (sunrise, sunset, and winter), sunlight has an easier time directly entering the eye damaging the internal structures, as well as some of the external ocular tissues. This means wearing your sunglasses is not only important during the warmest parts of the day, but any time your eyes are in direct sunlight, and especially around sunrises and sunsets. Clouds don’t protect you either. In fact, they give us a false sense of protection, and can be the culprit of some of the worst UV damage. 

What are some repercussions of sun damage when it comes to the eyes? 

• Photo keratitis - Most commonly seen in the mountains, and commonly referred to as snow blindness, photo keratitis is a sunburn on the eyes. Additionally, it is one of the more painful things you can experience related to the eyes

• Pterygium - In Southern California, these are quite common due to both the high number of field workers with high sun exposure, as well as surfers - in fact, its common name is surfer’s eye . Pterygiums are growths which can change your prescription, cause ocular surface disease, and eventually need to be surgically removed. 

• Skin cancer - The skin around the orbit is extremely sensitive. Many people struggle to adequately use sunscreen, as it stings the eyes, leaving the extra ocular tissue quite unprotected. 

• Cataracts - Most people will develop cataracts in their lifetime. However, people nearer the equator develop cataracts earlier in life due to the additional amounts of UV radiation absorbed by the lens. Cataracts are the leading cause of reversible blindness worldwide. 

• Age Related Macular Degeneration - ARMD is a multifaceted disease, but we have known for many years UV light exposure is a contributing factor to both the development of the disease, as well as it’s progression. 

• Solar Maculopathy - Sun gazers may be disappointed to learn permanent damage can occur from directly looking at the sun. Think of your eye as a magnifying glass, and your macula (central vision) is getting all of that direct radiation. If you have ever burned a leaf with a magnifying glass, you know it does not take long to burn a hole right through the entire structure. 

Sunglasses can help to reduce progression, or prevent the development of these common ocular diseases. Next time you have a fun day planned, remember to bring your UV protection (and not just for your skin!)