Blog #17, Part 3, Myopia control
for your child?
This week we will
discuss near-sightedness, otherwise known as myopia. It is a condition of the eye where the focal
point is too short for the length of the eye.
In the past few years there has been a considerable increase in the incidence
of myopia in the world. Myopia can be
passed on from your parents. If you wear
glasses, chances are good your child will also need glasses at some point. Though if you don’t wear glasses, your child
can still develop myopia . Regular eye
exams are important as your child grows.
Myopia can start in early child-hood, increasing in magnitude even to
the mid-twenties. Severe myopia can be a
big problem, with increased incidence of retinal detachment, debilitating dependence
on optical corrections, and even making it less likely for future laser
correction. The increased incidence of myopia,
and its consequences have driven a lot of recent research in trying to slow down the development of myopia.
There are
presently four accepted ways to slow myopia, some are better than others. First, myopia-control spectacle lenses with off-centre
defocus can help, as long as the child’s eyes stay aligned with optical centre
of the lens. Second, there are
orthokeratology lenses, a type of hard contact lens that are worn at night
only, correcting myopia and creating peripheral defocus zones that are always
centred , unlike spectacles. Third, there
are atropine drops at a very low concentration (made by a sterile compounding
pharmacy), which are quite effective in slowing the condition. And lastly, soft
contact lenses with a distance-centre multifocal that are worn all day
long. The last three are very effective,
with up to 30-40 % reduction in myopia, depending on the child and their age. What is really interesting is that a combination
of two of these, simultaneously, can produce a cumulative effect, even up to 45
% in some cases. A word of caution here- Noel
Brennan et al. have gone over these studies and found
that they use absolute percentages which are likely to be unrealistic, and
advise that future studies are needed to attain more conclusive relative
percentages.
Where does all
this leave us? The final numbers may not
be as high as reported, but there does appear to be sufficient evidence to
support these interventions. The optimum
time for help is in the 7 to 15 year old range and the best method to use depends
on the child and the family situation.
Best to have your child’s eyes checked early and regularly to catch any
trends and ensure that treatment can be given during these years. Do your research and when you see your
optometrist ask a lot of questions.
Til next week,
The Good Doctor, Dr. Mark Germain, Burlington Optometrist
