Children with amblyopia (commonly known as lazy eye) need only
wear an eye patch for three to four hours a day for 12 weeks to
improve vision, and those aged under four around three hours,
rather than the six to 12 hours usually recommended by doctors,
according to a new study as quoted by media reports
Friday.
The study involved 97 children aged 3-8 years with a confirmed
diagnosis of amblyopia. All children had a full ophthalmic
assessment and were instructed to wear glasses all the time for 18
weeks.
Three children are wearing
eye patches. Children with amblyopia need only wear an eye patch
for three to four hours a day for 12 weeks to improve vision, and
those aged under four around three hours, rather than the six to 12
hours usually recommended by doctors. (photo: file photo from
Xinhua)
On completion of this phase, researchers at City University in
London and McGill University in Montreal asked 80 children who
still met the study's definition of amblyopia to wear a patch for
either six or 12 hours a day.
The patch was fitted with sensors that were wired to a data
logger, which recorded how long the patch was actually worn. Visual
function was recorded every two weeks.
The point of the study was to see which eye patch "dose" was
more effective.
It is found that, on average, the six-hour group wore the patch
for 4.2 hours a day, while the 12-hour group wore it for 6.2
hours.
However, the visual improvement between the two groups was the
same.
Wearing the patch for less than three hours led to a much slower
improvement across the two groups.
Children under four years of age required significantly less
occlusion (under three hours a day) than older children to correct
their vision. Patching beyond 12 weeks did not confer additional
benefit.
This analysis suggests that achieving an initial dose rate of
three to four hours a day should be a clinical priority.
Eye patching can cause considerable distress for both the child
and family, researchers said, so doctors should try to minimize the
"dosage" for the best expected outcome.
Blurred vision or crossed eyes are the typical symptoms of
amblyopia, caused by a disturbance in the pathway of vision between
the eyes and the brain.
(Agencies via Xinhuanet.com September 14, 2007)
