Dr. Sanjay Agarwal, Great Lakes Optometry http://www.greatlakesoptometry.ca/

This question can be reworded into: “Why everyone should wear sunglasses?” Obviously, the avid runner will have more exposure to sunlight because running is generally an outdoor activity.   Therefore, wearing sunglasses would be more important for them, but realistically sunglasses should be worn by everyone including young kids.  Please read below:

Although, the sun is over 93 million miles away from us, it poses many ocular hazards.  The principal one is ultraviolet radiation or UV light.  UV light can be divided into 3 types based on wavelength which include:  UV-A, UV-B, & UV-C.  UV-C light is absorbed by the earth’s ozone layer and poses little risk to us.  UV-A & UV-B light, in contrast, can cause both short-term and long-term damage to the eye.

Photokeratitis is a condition caused by exposure to excessive amounts of UV-A&B light over a short period of time.  This could occur during running, for example, or using a tanning bed without protective goggles.  Fortunately, photokeratitis has short-lived symptoms like: foreign body sensation, excessive tearing & photophobia, and rarely causes long term damage.  Long-term damage is a cumulative effect which means the longer you are exposed to UV light, the more likely you will have damage.  An individual’s length of exposure to UV light will be directly proportional to the following:

Age – the longer you live, the more exposure you will have

Geography – sunlight is more intense at locations closer to the Earth’s equator so someone living in Florida will generally have more exposure than someone living in Canada

Hobbies – outdoor activities like running, skiing, and beach volleyball will increase exposure

Vocation – Lifeguards or farmers will have more exposure than office workers

Some of the more common examples of ocular long-term damage to UV light include cataracts, pterygia which is a growth over the surface of the eye, and retinal or macular degeneration.  Macular degeneration causes permanent eye damage.

When searching for sunglasses, the most important factors are the following:

* Lenses that block out 99% of UV A&B light

* Lenses that block out 70-90% of visible light

* Lenses that are free of imperfections or distortions

* Lenses that are gray, brown or green

Investing in a good pair of sunglasses is a sound and relatively inexpensive way to keep one’s eyes healthy.  Amongst good nutrition, it is one of the best ways to keep one’s eyesight for a lifetime.