Cosmetic lenses are used to change the colour of the eye, and are also known as plano or zero-powered lenses.
Trading standards officers and health experts say young people are known to share them, leading to an increased risk of corneal ulcers and infections.
เจ้าหน้าที่มาตรฐานการค้าและผู้เชี่ยวชาญ
Alistair Bridge, director of strategy at the General Optical Council said: "Opticians make sure that contact lenses fit properly and that wearers receive expert advice on how to wear and store them safely.