Wearing hard contact lenses at night could raise infection risk: study

The use of certain night-time contact lenses could increase the chances of children developing an eye infection that can lead to blindness if not treated, researchers at Chinese University say.

Orthokeratology, also known as “ortho-k”, is a procedure that uses hard contact lenses to temporarily reshape the cornea in order to improve problems such as myopia, far-sightedness and astigmatism.

The lenses are analogous to dental braces, but unlike braces, if the wearer stops using the lenses their eyesight problems will return.

The lenses are designed to press on certain parts of the cornea. If children wear them each night, then after a period of two to three years the lenses could damage the corneal epithelium or protective skin of the cornea, increasing the risk of infection, said Dr Vishal Jhanji, director of refractive surgery at the Chinese University’s specialist eye centre.

The university’s retrospective study looked at 18 cases of microbial keratitis – an infection of the cornea – in patients under the age of 18 at the Prince of Wales Hospital between 2001 and 2010. Some 40 per cent of cases were associated with the use of ortho-k. 

Between 2001 and 2008, over 100 cases of microbial keratitis associated with ortho-k have been recorded globally, mostly in East Asia.

“It’s not a condition to be taken lightly,” said Dr Alvin Young of Prince of Wales Hospital.