U ophthalmologists point a critical eye at vision myths

Wearing contact lenses too long can restrict oxygen flow to the cornea.

by Yelena Kibasova

There are 6-year-old children wearing glasses today while their grandparents still have near-perfect vision.

First-year biology student Nissma Eldeeb depends on good eyesight as a member of the University Community Darkroom Club. Her 20/20 vision comes in handy when pursuing her photography hobby.

“Some of my friends wear contacts and glasses and they say that they feel like their vision keeps getting worse and worse,” Eldeeb said. “But I’ve also heard that it doesn’t, so I’m not really sure.”

The perception that wearing glasses or contact lenses eventually weakens people’s vision or makes their eyes dependent is a myth, said Andy Dhaliwal, an ophthalmologist in the ophthalmology department at the University’s Medical School.

“It’s not like using crutches and the muscles in your legs get weak,” said Jeffrey Christensen, an ophthalmologist at the Minneapolis Medical Eye Clinic. “The only thing that causes dependence is that you learn that it’s fun to see well. That’s how you become dependent on it.”

While physically a person’s eye does not deteriorate, some continue to believe otherwise.

“Once (people) get a prescription… they might think after a while that, “Oh my vision couldn’t possibly have been that bad before,’ once they take their glasses off,” said Sara Mabie, an optometrist affiliated with Target Optical in St. Paul.

However, wearing contact lenses improperly can have an impact on your eye’s health, Dhaliwal said.

He said it’s important not to wear contact lenses for extended periods.

“Glasses you can wear as often or as little as you want. With contact lenses, generally the less you wear them, the better,” he said. “If the eyes are feeling uncomfortable, you should take them out and give them a rest.”

Wearing contact lenses too long can restrict oxygen flow to the cornea, he said.

“That can cause scarring over the long term, which can decrease the quality of your vision,” Dhaliwal said.

Eventually blood vessels start to grow into the cornea to get more oxygen, he said.

Another consequence of prolonged contact lens wear is that the eye can develop an allergy to the lenses and eventually reject them.

Eyes can also get corneal infections (or corneal ulcers), especially when contacts are worn overnight, Dhaliwal said.

“That’s the real serious one,” he said. “That can cause permanent loss of vision or even rarely loss of the eye if it’s not treated quickly or appropriately enough.”

Dhaliwal recommended not wearing contacts overnight, even if the prescription says it’s OK.

Parents tell their children to not sit too close to the TV or not to read in the dark because it will hurt their vision.

Mabie said reading in the dark might make a person uncomfortable, but “if your eyes are going to change, they’re going to change whether you read in the dark or not.”

While some believe methods such as eye exercises improve one’s vision, no such techniques have been found to be helpful.

“There’s not a muscle in your eye that you use to bring sharp vision,” Christensen said.

Mabie said some therapies do work to correct other eye problems.

“There are vision therapy techniques that certainly help different types of conditions,” she said.

For example, if one of the eyes tends to wander to one side, therapy can help the eyes work together, Mabie said

Dhaliwal said it’s important to keep eyes healthy. He recommended getting yearly eye exams, minimizing contact wear and avoiding over-the-counter lenses.

“It’s extremely important that you have them fitted by either an optometrist or an ophthalmologist,” he said. “If they don’t fit correctly, it can cause many problems.”