By Susan-Elizabeth Littlefield

MINNEAPOLIS (WCCO) — This Halloween, some Minnesota doctors have a warning, and it has nothing to do with candy.

The Minnesota Optometric Association is warning people to be leery of festive eye contact lenses. People use them to look like cats or zombies and other costume-inspired looks. The association says there’s a black market for the non-prescription kind.

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Before they hit the Trail of Terrors in Zimmerman, Minn., those playing the ghouls have to get into character.

“We have 50 creeps, they’re referred to, our actors,” said Bill Potrament, who manages the Trail of Terrors.

Before sunfall on Friday, the makeup room was abuzz with zombies and high school thespians covered in make-up.

Potrament says they don’t skimp on the details, except when it comes to decorative contact lenses. He says organizers made a decision not to have the cast wear decorative contact lenses.

“It’s not something that, doing any research, we were comfortable with,” he said.

They’re risky, much to the dismay Zimmerman High student actor Shelby Horstman.

“I think they’re kinda cool, they’re freaky,” she said.

Potrament says it was a thought out decision.

“There’s been a lot of discussion about misuse of them,” he said, “about bacterial infections that are associated with them.”

The Minnesota Optometric Association just released a warning, saying the wrong kind of lens can cause infection and vision loss.

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They say the only safe ones are the ones that require prescriptions.

Even without the contacts, Potrament insists there’s plenty to look at.

I talked to the owner of the Halloween Fun stores. He says they sell the contacts but require prescriptions. The real danger the Optometric Association warns of are places that sell generic ones.

The association sent us this contact tip list:

Wear contact lenses only if they are fitted and prescribed by an optometrist.

— Do not purchase contact lenses from gas stations, video stores, or any other vendor not authorized by law to dispense contact lenses.

— Never swim while wearing contact lenses. There is a risk of eye infection when contact lenses come into contact with bacteria in swimming pool water.

— Make sure contact lenses are properly cleaned and disinfected as instructed by your eye-care professional.

— Make sure you wash your hands before handling and cleaning your contact lenses.

— Never swap or share contact lenses with anyone.

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— Never sleep while wearing contact lenses unless they are extended-wear lenses specifically designed for that purpose.

Susan-Elizabeth Littlefield