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GLASSES FOR INFANTS AND CHILDREN
Dr Justin Mora - Eye Surgeon, Auckland Eye
Why are glasses prescribed for children?
Glasses are prescribed for children to improve vision,
to prevent and treat amblyopia (lazy eye), or to correct
eye muscle problems.
More specifically, glasses may be required for:
1: Myopia (short-sightedness)
Light rays entering the eye focus in front of the receptor
cells in the retina. Myopes may see clearly at near but
are blurred at distance.
2: Hyperopia (long-sightedness)
Light rays entering the eye focus behind the retina. The
eye has to exert extra focusing power to see clearly at
distance and even more so at near. If the hyperopia is large
then the eye may not be able to focus the image clearly
at all. Most young children have mild degrees of hyperopia.
3: Astigmatism
Light rays entering the eye focus at different places.
It is caused by an irregular surface of the eye. Instead
of being perfectly round, the surface of the eye is shaped
like a rugby ball lying on its side and is more curved in
one plane than the other.
4: Refractive Esotropia
There is a link between the focusing muscle in the eye
and the muscles which draw the eyes together as we look
at a near object. Some children with hyperopia are required
to exert so much focusing power in their eyes that their
eyes turn in. This refractive esotropia may be fully correctable
with glasses.
How are young children tested for glasses?
A retinoscope is used to shine a beam of light into the
eye. Movement of the light gives a characteristic reflection
in the pupil indicating hyperopia, myopia or astigmatism.
Lenses of varying power are placed in front of the eye until
the refractive (focusing) error is cancelled out.
In young children it is necessary to dilate the pupil
and relax the focusing muscle with eye drops to get an accurate
test. The eye drops make the child a little light sensitive
and blur the vision for several hours. The drops take 45
minutes to work.
How are glasses prescribed?
A prescription is given for each eye. The higher the first
number on the prescription, the greater the correction required
in the lens. If there is a second number then this means
there is some astigmatism and the higher the number, the
greater the astigmatism.
A plus sign in front of the first number indicates a hyperopic
prescription while a minus sign indicates a myopic prescription.
The prescription is taken to an optometrist or optician
who will prepare the lenses.
What type of lenses are the best?
Glass lenses should be avoided in children because they
are more likely to break. Plastic or polycarbonate lenses
are lighter and safer but they scratch more easily. The
lenses must be made with a scratch-resistant hard coating.
Some high power prescriptions can result in thick lenses
and your optometrist or optician can advise you on modifying
a lens to make it more cosmetically acceptable. High density/thinner
materials can be used and the edges of the lenses can be
thinned to improve the appearance.
What kind of frames are suitable for children?
The frame you choose for your child should be comfortable,
safe, sturdy, and attractive.
Whenever possible, purchase the glasses from an optometrist
interested in working with children, and ask for a recommendation
on the most suitable frame style for your child's facial
features, age, prescription power and activities.
Enquire about a frame guarantee, as these may be available
on certain frames.
Some frames can be fitted with clip-on sunglasses. They
are not essential, but sunglasses are advisable for all
children on bright days.
Normal adult ear pieces are usually unsuitable for children
and adjustments should be made so the glasses will sit more
securely.
For infants, straps may need to be substituted for ear-pieces
to help keep the glasses in place. Flexible hinges are advisable
as children tend to be careless when removing their glasses
and flexible hinges tolerate a lot more abuse.
If the child is old enough, let him or her help select
the frame, but follow your optometrist's advice about size
and fit as a child will not wear uncomfortable glasses.
How can I keep glasses on my child?
It is most important that parents are positive about the
glasses. They should not make a big fuss about them but
they must encourage the child to believe that the glasses
suit him/her.
If your child is an infant or toddler, distract him/her
after you have put on the glasses.
If your child removes them, then replace them immediately.
If the child removes them again, then put them aside for
a short time and then try again. You must be patient but
persistent in having the child wear the glasses.
Should my child wear glasses all the time?
Usually when a child is prescribed glasses it is because
the child needs to wear them all the time. Some children
have amblyopia (lazy eye) with poor development of the visual
pathways to the brain because the image into the eye has
been blurred. In this situation it is essential that the
child wears the glasses all the time so that the brain can
learn to recognize clear images. If one eye is more long
or short sighted than the other, and sees more poorly even
with the glasses then the better eye may need to be patched
(covered up) for part of each day in order to build the
vision in the lazy eye.
How do I care for my child's glasses?
Children should be taught to remove their glasses using
both hands without twisting the frame.
They should keep them in a protective case and not put
them face down on any surface. Use water or liquid soap
and a soft cloth to clean them and avoid rough paper towels
or tissues.
If the glasses are damaged or badly scratched take them
back to your optometrist for repair or replacement. Children's
glasses usually need to be readjusted every few months;
more frequently than for adults.
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