Protect skin from ultraviolet radiation.

Make sure to apply that sunscreen.

Don’t frequent tanning beds.

These lessons are drilled into health books and brochures, and they all lead to the same conclusion: it is imperative to protect skin from the sun. But how often do people seriously consider what UV rays might be doing to eyes?

Exposure to sunlight is a double-edged sword, according to Mac Abernethy, a licensed optician for Academy Eye Associates office in Durham. Sunlight is good for eyes, he said, but only in healthy doses.

According to Abernethy, though all sunglasses are now mandated to have ultraÉviolet filters, higher-end sunglasses offer the best protection against harmful UV rays.

“Years ago people didn’t have medicine,” Paul Massie, a sales associate at Sol Mio in Crabtree Valley Mall, said. “Look at it this way, UV protection and polarization, like medicine, is just another way of living a healthier life.”

According to Massie, polarized lenses prevent glare. For example, he said, when someone looks at a pool he wouldn’t see a reflection, he would see the depth.

Rodney Bradshaw, a certified ophthalmic technician at Doctor’s Park Eye Center in Jacksonville, said polarized sunglasses are the most efficient form of eye protection.

Excessive sunlight exposure — which can be prevented by protecting the eyes with sunglasses — has been linked to cataracts and pterygium, a benign growth that affects the tissue on the white part of the eye, Bradshaw said.

According to Abernethy, cataracts may be effected by UV exposure, but are predominantly a result of genetics. People who have lighter eyes are more likely to be sensitive to the sunlight because there is less pigmentation, he said.

“For many cheaper sunglasses the UV protection is on the surface and can evaporate when left in the heat for an extended period of time,” Massie said. More people are starting to wear Ray-Ban because of their ability to protect eyes from the sun’s harmful rays, he said.

“I had a friend in high school that did an experiment where she put living bacteria under different kinds of sunglasses, and put the sunglasses in tanning beds,” Massie said. The only glasses that kept the bacteria from dying were the Ray-Bans.”

Amos Williams, a senior in fisheries and wildlife sciences, wears sunglasses when he works outside for a lawn care business. He said eye care is not one of his major concerns — especially when temperatures hit the triple digits.

According to Bradshaw, there are ongoing studies that try to determine whether a person’s lens turns yellow as he ages to protect the retina from sunlight.

“A certain amount of sunlight helps keep the eyes healthy and disease-free,” said Abernethy. “But once damage is done, it is irreversible.”