Science

Volunteers wanted for vision study

Corneal shape before lens wear
Tuesday, 22 February, 2011
Bob Beale

Do you keep losing your reading glasses? Fed up with searching for brighter light or holding things at arm's length so you can focus on what you are seeing?

A research project has raised hope that there may be a new way to correct your near vision without having to rely on glasses.

Researchers in the UNSW School of Optometry and Vision Science need volunteers from the Sydney region to help discover whether special contact lenses worn during sleep can replace the need for reading glasses in adults.

"As you age, the lens inside your eye loses flexibility making it harder to focus on close objects," says researcher Dr Paul Gifford. "This condition is called presbyopia and the incidence is 100% in older adults – in short, its normal and it happens to everybody past the age of about 45.  We all need reading or multifocal glasses sooner or later.

"These specially designed contacts, known as orthokeratology (OK) lenses, are already widely used in adults to correct myopia, or short-sightedness. You pop them in at bedtime and they gently reshape the surface of the eye while you sleep. You remove them on waking and you can see well all day without glasses."

Dr Gifford recently developed a new kind of OK lens designed to correct hyperopia, or long-sightedness, showing for the first time that such lenses could reliably and predictably correct low levels of hyperopia.

Intriguingly, while doing that research it emerged that the range of near focus also improved in people who wore the lenses. This raised the prospect that these lenses could be used to correct presbyopia.

“I’m sure most people will agree that having to wear reading glasses is a real pain!” says Professor Helen Swarbrick, who leads the Research in Orthokeratology Group. “With a globally aging population the numbers of people with this problem can only increase, so innovative corrections that avoid the need for reading glasses will be in great demand.”

In this new study, the researchers are seeking 20 people aged 45-65 years who need to wear glasses or contact lenses only for reading. Participants will be asked to wear the lenses overnight only for periods of up to 3 months. They will need to attend the group's clinic at the UNSW Kensington campus for routine optometric measurements in the morning and afternoon after the first night of lens wear, at the end of the first and second weeks, and monthly thereafter. Participants will be provided with a pair of lenses at the end of the study to keep if this form of refractive correction suits them and if they would like to continue with orthokeratology correction for their near vision.

Eye care practitioners in the Sydney region are encouraged to refer suitable patients who might be interested in participating in the study.

For more details about this and other projects by the UNSW team email ROKInfo@unsw.edu.au