Do you have the perfect costume in mind? Does it involve changing your eyes from a natural brown to a deep red or green?

Cosmetic contact lenses are often sold in joke and costume shops, but often come without instructions on how to safely apply them and use them.

But they look really cool!

Especially when you have makeup that goes with them.

They can also be really freaky looking.

And they make for an incredible costume.

But how safe are they?

Laura Butler did not know the risks associated with these colorful accessories when she purchased a pair without a prescription. Within ten hours she felt extreme pain in both eyes and went to visit a doctor.

She found out that she contracted a severe eye infection, a scar on her cornea and damaged vision.

"Because I had not been properly fitted by an eye care professional, the lenses stuck to my eye like a suction cup," she said.

She now has to live with the long-term effects of her decision.

"I was in severe pain and on medication for four weeks and couldn't see well enough to drive for eight weeks,' she said. 'I now live with a corneal scar, vision damage and a drooping eyelid," she said.

Eye care professionals are now issuing a warning against this costume accessory as they can lead to vision impairment or loss.

The Association of Optometrists say that people should only wear lenses sold with the supervision of a registered eye health professional.

Eye problems tend to increase around Halloween with cases of infection and irritation.

"Some of the cases we see, like patients sharing lenses with friends, wearing the same pair year after year well past the expiry date, and storing them in tap water, have devastating effects," he said.

Those who don't usually wear contact lenses are at a higher risk because they don't know how to properly care for them.

"Most people think that you don't need the same level of care when using novelty contact lenses as you do with ordinary contact lenses, because they don't have a prescription. But, even when purchased from a reputable outlet (the issue isn't with the lenses themselves, but with how people use them). Fancy dress lenses are often purchased by people who do not wear contacts regularly and who may not know how to handle and care for them safely. It is absolutely vital for the health of your eye that you are able to remove and insert your contact lenses safely, know how to keep them sterile, and have been instructed on how to do so by an optometrist."

The risks are just not worth it to win that costume contest.

"Not knowing the basics of using contact lenses safely can put you at higher risk of developing painful eye injuries and, in the worst cases, risk of permanent sight loss."

Source: BBC / Alexander Bain & Murray Opticians / Daily Mail