Putting the contact lense on your eye does carry risks with it

Nick Coleman, Chrome-X

The lenses were until recently available only through registered opticians, distributed by a firm called Chrome-X.

Opticians sell lenses only after a full eye test and advice and offer check-ups afterwards.

But the lenses are now being sold without prescription for cosmetic use at body piercing parlours and fashion accessory shops.

Nick Coleman at Chrome-X backs opticians advice that they should only be purchased with expert advice.

He told BBC Radio Five Live: "One optician said to me one he gets the message home to people by saying 'You wouldn't wear somebody else's false teeth would you?'

"Contact lenses have for some reason been seen as a fun element. I think they have missed the point that putting the contact lens on your eye does carry risks with it."

He said that though he had not heard of any cases of infection being contracted the risk remained real.

Mr Coleman added: "They should go to an optician as they are trained, they are professionals and they can advise on the best way of cleaning them and caring for them."

Opticians could "stop people running into problems" by checking their suitability and carrying out an eye test.

Contact lens use is thought to be the most significant cause of microbial keratitis, a condition in which the outer layer of the eye, the cornea, becomes inflamed after infection by bacteria, fungi or amoebae.