The sun can have grave impacts on our eyes—which, believe it or not, are susceptible to sunburn, just like our skin is. Excessive sun exposure can also increase the risk of cataracts, as well as macular degeneration. Not to mention, excessive sun exposure on the front of the eye can lead to unsightly growths called pinguecula that can eventually develop into damage to the eye that requires surgical intervention. In short, the sun can be scary, and it’s important to block off harmful rays.

Enter: sunglasses.

Far beyond being a stylish accessory, sunglasses play a critical role in protecting our eyes from the sun.

Without getting too technical, some lenses, depending on which type of lens material is chosen, inherently block 100% of UV rays, whereas some lenses require an additional coating to block UV radiation. That being said, not all sunglasses are created equal. When shopping for your next pair of shades, it’s important to consider quality and whether your sunglasses are really doing their job.

What to look for when shopping for sunglasses Any strong sunglass contender will, first and foremost, contain a UV coating, or will be made from a material that blocks 100% of UV rays. It’s the most critical part of a good pair of sunglasses and is simply essential for filtering out UV rays. If eye protection is a priority for you (and it should be!), make sure you choose your lens material with 100% UV protection, or ask to add on a UV coating.

Sunglasses can also be topped with additional enhancing elements, including:

1. A mirror coating, which offers another layer of protection, as it reflects light away from your eyes, similar to a mirror. Along with its protective powers, a mirror coating (which is applied to the front of your lenses) helps stave off eyestrain and squinting, making it easier to see clearly in the sunlight.

2. If mirror coatings aren’t your style, opt for an anti-reflective (AR) coating, which also reduces reflections. AR coatings work to mitigate irritating light reflections, allowing you to see a sharper image.

3. At FYidoctors, we’re big fans of polarized lenses—which, in our eyes, make for the highest-quality sunglasses. Polarized lenses eliminate glare (which, in certain environments, can feel blindingly bright) and improve clarity, comfort and overall vision.

Why pick polarized sunglasses? Unpolarized light exists all around us. It can come from the sun, a light bulb, or even a flame. Unpolarized light sources emit vibrations or waves that move in all directions.

When the direction of these vibrating light waves hits a smooth surface and reflects, the light becomes partially polarized. This is also known as glare, and is caused by too many waves of light becoming partially polarized and angled horizontally toward our eyes.

Excessive amounts of partially polarized light can be harmful to our vision. Over-exposure to bright light and glare can cause squinting, eye fatigue, and even temporary blindness in extreme cases. You will know your eyes are being impacted when you are outside in a bright environment and find yourself shielding your eyes from a flash of glaring light.