By Michael Hutton 

Contact lenses for children  which are designed to correct short-sightedness but are only worn while sleeping can prevent the child's prescription from worsening according to a new study from the University of New South Wales (UNSW) in Sydney, Australia. These special overnight contact lenses can be worn by children as young as 6 and use a long-established vision correction technique known as ‘orthokeratology' (‘ortho-k') whereby the front surface of the eye is gently reshaped during sleep. The lenses are removed in the morning and the wearer then enjoys clear natural vision for the rest of the day. Professor Helen Swarbrick, who heads the UNSW Research in Orthokeratology Group, says "Our research has demonstrated conclusively that ortho-k is effective in stopping the eye growth - referred to as ‘elongation' - that causes myopia progression."

The finding suggests that ortho-k lenses may help to reduce the growing incidence and severity of myopia throughout the world and especially in Asia. In Taiwan, as many as half of all children in kindergarten wear glasses and by the age of 18 about 9 out of 10 Taiwanese are myopic. According to Professor Swarbrick notes, "It's been suggested that genetic factors, dietary change and a surge in people doing more close work - that is, reading, watching TV and looking at computer screens - are involved but we don't really know. What we do know is that using these overnight ortho-k corrective contact lenses for children  can halt the progression of the condition and that will have a major social benefit in the long-term."

The achieved correction lasts for at least 24 hours so the lenses are reinserted at night to maintain the corrected vision and the lens wearer can see equally well with the lenses in or out. Unlike surgical techniques, the correction achieved this way is reversible - simply by not wearing the lenses, the eyesight will return to its original prescription. "The effect is dramatic," says Professor Swarbrick. "After a single night of lens wear, vision can improve by as much as six to seven lines on the standard optometrists' vision chart." A trial undertaken by UNSW with 24 children yielded compelling results: wearing an ortho-k lens inhibited the elongation of their eyes while wearing a normal daytime contact lens did not. Thus overnight ortho-k corrective contact lenses for children  appear to offer an effective way of preventing childhood short-sightedness worsening.

Check if your child is suitable for overnight ortho-k corrective contact lenses .