Sleep
on it: lenses may fix vision
Sydney Morning
Herald, April 24, 2004
Contact lenses worn only
while sleeping could help correct long-sightedness
by altering the shape of the eye.
University of NSW researchers have found the
first scientific evidence that special orthokeratology
contact lenses worn at night can correct long-sightedness
during the day.
The research leader, Helen Swarbrick, said the
lenses held promise as a safe, simple and reversible
treatment for people who could see well into
the distance but had trouble seeing close objects.
"Although the study involved only a small
number of subjects, it's very promising that
we were able to achieve a measurable change
even in such a short time," Dr Swarbrick
said. Study subjects reported improvements in
vision after wearing the "steep" ortho-k
lenses for four hours. A more extensive research
program would start later this year.
Nina Tahhan, an optometrist who conducted the
research with Dr Swarbrick, said the steep ortho-k
lenses were designed to correct the too-flat
eyeballs that cause long-sightedness. They work
by drawing the cornea out while the person sleeps,
thereby lengthening the shape of the eye and
correcting its point of focus. "It's still
in the very early stages but this study was
the first one to show that corneal change can
happen in that direction," Ms Tahhan said.
"Flat" ortho-k lenses have recently
become available to the public to correct myopia,
or short-sightedness, which is caused by a too-long
eyeball.
The idea arose after optometrists read about
the ancient Chinese practice of sleeping with
small sandbags on the eyes to correct poor vision.
Ms Tahhan said after one week of wearing ortho-k
lenses to correct her own myopia, she no longer
needed to wear glasses.
"It's not a permanent change - if I stopped
wearing the lenses at night my sight would return
to its previous point," she said.
"But some people have such good results
with ortho-k they only need to wear them once
or twice a week."
AAP
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