The price of a pair of sunglasses won’t necessarily determine if the shades will adequately protect your eyes. There are other things you should look for.

The cheap sunglasses from the drugstore you just had to have may end up costing you more than the fiver you put down to buy those slick shades.

They could cost you your eye health.

Indeed, as the summer is heating up and the sun is in the sky longer, eye doctors and experts are warning that not all sunglasses can protect your eyes from harmful ultraviolet (UV) light.

“The biggest danger with poor sunglasses is if the glasses are tinted but do not block the UV rays. The tinting in the glasses causes the pupils to dilate, since it is perceived as being darker, without the UV blocking. Then more ultraviolet radiation is able to enter the eye,” Dr. Benjamin Bert, an ophthalmologist at MemorialCare Orange Coast Medical Center in California, told Healthline.

Regular exposure to UV light can have cumulative and profound consequences.

Cataracts, macular degeneration, ocular melanoma, and eyelid cancers may be caused by UV exposure to the eyes.

Even a sunburn of the eye (photokeratitis), like the one you might experience on your skin, is possible.

“The longer the eyes are exposed to UV radiation, the greater the risk of developing these conditions,” Dr. Amanda Rights, an optometrist and brand ambassador for the company that makes Transitions lenses, told Healthline.

The lack of UV-blocking protection around your eyes may also cause skin cancer.

“The UV rays not only cause glare, but damage to your eye health and the delicate skin area that surrounds your eyes. It’s been shown that 5 to 10 percent of all skin cancer occurs in the eye area, so opting for a pair with polarization and UV protection is extremely important,” Samantha Brown, stylist and partner with sunglasses brand Maui Jim, told Healthline.

What sunglasses should do

Look for sunglasses with a sticker or tag that promote their UV-blocking capabilities.

Rights says you should only buy lenses that provide at least 99 to 100 percent protection against both UVA and UVB rays. Even better, look for shades that block 75 to 90 percent of visible light.

You also want to look for shades that feature an antireflective treatment on the back side of the lenses.

“Up to 50 percent of UV rays that reach the eyes come from reflection off the back surface of the lens,” Rights said.

Micro sunnies, seen on many celebrities in recent months, may be stylish, but they’re a recipe for disaster, Rights says.

“They don’t offer the coverage needed to protect your eyes and skin,” she explained.

What you should look for instead are frames that fit your face well and cover as much of the delicate skin around your eyes as possible.

“Wraparound-style glasses or surf-style glasses with larger temples or ‘arms’ block more than thin-framed glasses and help to protect you from the side,” Bert said. “It is important to remember when you are out on the water, or other reflective surfaces, that you are getting exposed to the sun’s rays from above and those reflected from below. Having glasses that fit appropriately to protect you from multiple angles is important.”

Sunglasses as important as sunscreen

“As a professor once taught me, think of sunglasses like sunscreen for the eyes,” Bert said.

In other words, don’t leave home without them.

“Wearing sunglasses when you’re in direct sunlight is as important as wearing SPF every day,” Brown said. “Eye health is top priority for myself and my clients because I have a personal history with the damage those UV rays can do. My mother battled skin cancer next to her eye, which was caused by a lack of sun protection. She underwent painful reconstructive surgery and is fortunate enough to be a survivor.”

A third protective measure, a wide-brimmed hat, can help cover any skin the sunglasses and sunscreen miss and block more UV rays.

Color and cost don’t mean a thing

“Many of the cheap sunglasses that are available at dollar stores, drugstores, and gas stations are not verified to meet specific standards that eye care professionals suggest for adequate UV protection,” Dr. Harbir Sian, BSc, an optometrist in Vancouver, Canada, told Healthline.

Indeed, most of these glasses are just made with tinted plastic. While the tint might lull you into a sense of security, they’re not actually protecting your eyes.

However, a quality pair of sunglasses doesn’t have to be a costly investment.

Look for the most important number: how much UV the lenses block. Then find a frame that’s as large as you can handle without being so big it sits away from your face. That extra space lets too much light in.

The more protective factors you have — polarization, polycarbonate lenses, titanium frames — the higher your cost may climb.

But keep in mind that many people wear their sunglasses daily, so the investment might pay for itself if the protection benefits are good.

The bottom line

Reputable stores, clinics, and brands want you to know how great their sunnies are.They’ll promote their sun-protection factor and many other protective benefits. Some will even work with you to find the right fit for your face.

“If a patron is purchasing sunglasses from a reputable source, such as an optical store or optometry clinic, they can rest assured that the quality meets required standards, as these vendors will purchase from labs and manufacturers that follow strict guidelines,” Sian said. “However, if a person has a pair of sunglasses they are unsure of, they can always bring them in to their local optical or optometry office to have them confirm the quality of UV protection.”