The fad for coloured or patterned contact lenses which alter the colour of the wearer's eyes could lead to blindness and disease, say experts.
Coloured lens are widely available
The General Optical Council, the opticians' regulatory body, is calling for a crackdown on the sale of non-prescription cosmetic lenses.
It says the lenses should only be sold by, or under the supervision of, a registered doctor or optician.
At present, the lenses, which have been popularised by rock stars such as Marilyn Manson, are available without prescription from body piercing parlours, fashion accessory shops or on the internet.
This is because they are not classified as medical devices - and therefore are not covered by legislation.
However, the GOC is concerned that vendors often fail to provide information about how they should be cleaned and stored.
This, they argue, increases the potential for infection, particularly as children have taken to swapping them with their friends.
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.
Another infection which can be spread by poor hygiene is acanthamoeba, which can lead to ulceration of the cornea, and ultimately to blindness.
There is also concern that the lenses interfere with colour perception and with binocular vision.
And if they do not fit properly they can damage the surface of the cornea.
The lenses, which feature designs including Union flags and tigers' eyes, retail for about £25. It is estimated that 90,000 people have used them.
David Craig, of the Association of Optometrists, told BBC News Online there was a risk of people going blind if they failed to take proper precautions.
"If you buy lenses over-the-counter from a market stall you will receive no assessment as to whether you are a suitable person to wear contact lenses," he said.
"We are not saying that you shouldn't wear these lenses, just that you should only be able to buy them from somebody who knows what they are talking about.
"After all you have only got two eyes, so you had better look after them."
Mr Craig said he had seen instances of people who kept their contacts in storage cases which were full of mould.
A spokesman for the Department of Health said that ministers would respond to the GOC proposal in the autumn.