Prof. Pauline Cho of the School of Optometry recently conducted a study on 15 brands of coloured contact lenses. It was found that most of them had surface coloured pigments which would easily come off under a rub-off test. Furthermore, the cosmetic coloured contact lenses failing the rub-off test had higher levels of microbial adherences. The surface pigments on those lenses did not employ embedded or sandwiched design and this was likely the reason of higher microbial adherence on them. Details>>