ABC13's Chelsey Hernandez spoke with a retina surgeon on how you can test your sunglasses at home and what to look for when you buy.
"What people don't realize is that prolonged exposure of sunglasses to UV Rays from the sun will actually damage the coating of the UV protection," said Retina Surgeon Dr. Shawn Kavoussi with the Berkeley Eye Center.
SEE ALSO: Are refurbished headphones worth it? Top brands at half-price
Kavoussi says this could leave you open to a number of eye-related health issues.
"Sunglasses with UV protection are critical to protect your eyes and multiple structures in the eyes from damage. You can get damage from the sun even on your eyelids," said Kavoussi.
So how do you know if your sunglasses have expired?
There's actually a great way to test them at home. You can order a UV flashlight from Amazon and shine that against a $5, $10, $20, $50 or $100 bill. When the watermark from the bill lights up, put the sunglasses in front of it. If it disappears, then you'll know your sunglasses are still working.
So, how do you shop for the right lens protection?
"When you're shopping for sunglasses, you want to look for the 400 UV label that means the sunglasses will protect 99 to 100 percent of the ultra violet rays from the sun. You want to look for both UVA and UVB protection," said Kavoussi.
Certain types of sunglasses will also be marked with a "P" indicating they are polarized. Kavoussi explains it's different from UV protection, almost like an additive effect. Either way make sure you're buying glasses with the 400 UV label.
RELATED: How to prepare your home and A/C unit for the warmer temperatures