Contact Lenses Worn Overnight; What Is Hyperopic Orthokeratology?
A contact lens worn overnight in a treatment called hyperopic orthokeratology can restore vision by reshaping the eye's cornea, eliminating the need to wear corrective lenses during the day, according to a study conducted by a team from the University of New South Wales is Sydney, Australia.
While hyperopic orthokeratology, a technique that experts liken to braces for the alignment of teeth, is both groundbreaking and cost-effective in that it can eliminate the need for surgery and reading glasses in middle and old age, its effects are still temporary because the cornea will naturally and gradually spring back to its original shape if the lens isn't worn consistently. As a result, the technique is merely an alternative to easily slipping on glasses or getting surgery that doesn't wear out as fast.
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"This possibility will certainly appeal to many people, especially since the changes in the corneal curvature of the treated eye are fully reversible," said the New South Wales team in the Optometry and Vision Science journal.
In their study, the researchers studied 16 people aged 43 to 59 with age-related presbyopia, or near-vision loss, which is caused by the loss of flexibility in the cornea, the part of the eye which lets in light, as people age. As the Daily Telegraph notes, the team devised a "monocular" technique where patients wore a rigid lens in one eye each night for a week, but left the other eye untreated to preserve long-distance vision.
After the study concluded, it was found that the hyperopic orthokeratology technique was successful in restoring near vision in the treated eye, at least halving each patient's long-sightedness. At first, the effects of the technique didn't last long throughout the day with patients' vision beginning to return to normal, but by the end of the trial week, the improvements lasted until the evening. Furthermore, as the Daily Mail notes, long-distance vision in the treated eye and overall vision in the untreated eye were unaffected.
"The authors have shown the feasibility of correcting one eye for near vision through orthokeratology, in which overnight contact lens wear shapes the cornea of one eye to allow in-focus near vision for reading," said Dr Anthony Adams, editor of Optometry and Vision Science. "This study demonstrates that orthokeratology is quite viable as a nonsurgical option for monovision that does not require wearing contact lenses during the day, although it does require 'retainer' orthokeratology contact lenses to be worn overnight."
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