Imagine going for a car ride and sticking your head out the window as you race down the road ... with your eyes wide open and no sunglasses. Think how awful your eyeballs would feel after just a few seconds of wind and dust.

Or what if you're playing Frisbee in the park and you jump up to make a catch just as the sun hits you head on.

That's what software programmer Roni Di Lullo was thinking one evening as she was playing Frisbee with her border collie near their home in San Jose, California. As the sun was setting, her dog missed a catch (a rare occurrence) and Di Lullo figured sunglasses would make her pup's life easier. So she set out to craft a pair, reports CNBC. Dog sunglasses, specifically Doggles, were born. That was 1997; in 2015, sales were an impressive $3 million.

Dog sunglasses are incredibly cute and certainly attract attention. "If you are extremely introverted ... don't take your dog out in public with these on, because everyone will stop to admire and comment," wrote one Doggles reviewer on Amazon.

But does your dog really need them?

border collie wearing sunglasses This pup with Arizona Border Collie rescue has to wear sunglasses on the beach because her eyes have problems with the sun. (Photo: Doggles/Facebook)

The National Eye Institute suggests people wear sunglasses to protect eyes from the sun's harmful ultraviolet (UV) rays. Prolonged UV exposure can lead to cataracts (clouded vision), as well as conditions such as macular degeneration, the leading cause of blindness in the U.S.

UV rays aren't as big of an issue for dogs, however, mainly because of their shorter lifespans. They usually don't live long enough to develop UV damage in their eyes, animal eye care veterinarian Robert English tells Outside.

He said dogs still get cataracts, but they're either genetic, caused by diabetes, or they develop due to lens growth during old age. A dog's head structure also helps fend off sun damage in the eyes.

“Because of their deeper set eyes [in most breeds at least] and their heavier brow, their eyes are more shaded [by their brows] and have less of a direct angle to the sun than our eyes,” English says.

English says the glasses still might be beneficial for older dogs or those with certain eye disorders.

“Older dogs with early age-related cataracts arguably probably have slightly better vision outside on a sunny day if they wear polarized Doggles," he says.

Some vets suggest dog sunglasses may be helpful if your dogs are active in outdoor sports, especially in the snow or sun, or if your dog hangs his head out the car window (not a safe practice, by the way.)

The protective glasses are also worn by military dogs, especially those deployed in areas where there are sandstorms, reports the U.S. Army News Service.

military dog wearing Doggles in Afghanistan.A military dog wears Doggles to protect his eyes as a Chinook helicopter takes off in Afghanistan. (Photo: The U.S. Army/flickr)

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.