The most common reason your child may be prescribed glasses is to correct focussing errors and improve how well they can see. Glasses can also be used to prevent and treat amblyopia (lazy eye) or to correct eye muscle problems.
If you notice your child is squinting or is having difficulty seeing clearly, it is important to seek advice. In some cases, catching eye problems early can limit the effect of the problem. Common symptoms which may indicate vision problems include headaches, rubbing or shutting one eye when reading and poor concentration.
If your child has poor vision, glasses may be needed to correct:
- Myopia (short-sightedness) when light rays entering the eye focus in front of the retina, rather than directly on it. People with myopia may see things clearly close up, but things are blurred at a distance.
- Hyperopia (long-sightedness) when light rays entering the eye focus behind the retina. The eye has to exert extra focusing power to see things clearly at a distance and even more so close up. If the hyperopia is large, then the eye may not be able to focus the image clearly at all. Most young children have a small amount of hyperopia.
- Astigmatism when light rays entering the eye focus at different places. This 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.
- Anisometropia when each eye has a different focus and the eye that's worse may become lazy. In this situation the glasses treat the difference between the 2 eyes.
- 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 have to exert so much focusing power in their eyes that their eyes turn inwards. This is called refractive esotropia. It may be fully correctable with glasses.
How are young children tested for glasses?
To test eyesight, a retinoscope is used to shine a beam of light into the eye. The particular way the light is reflected in the pupil will show if there is any hyperopia, myopia or astigmatism. Lenses of varying power are placed in front of the eye until it is able to focus correctly.
In young children, eye drops are needed to dilate the pupil and relax the focusing muscle 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 40 minutes to work fully.
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's a second number then this means there's some astigmatism and the higher the number the greater the astigmatism. A plus sign in front of the first number indicates a hyperopic (farsighted) prescription while a minus sign indicates a myopic (nearsighted) 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 for children because they're 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. Your optometrist or optician can advise you on different ways a lens can be made more visually appealing. For example, high density/thinner materials can be used or the edges of the lenses can be thinned.
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. Ask for a recommendation on the most suitable frame style for your child's facial features, age, prescription power and activities.
- If your child is old enough, let them help select the frame. However, make sure you follow your optometrist's advice about size and fit. A child is more likely to be willing to wear glasses they like, but won't wear uncomfortable glasses.
- Adjustments should be made so the glasses sit securely. For infants, straps may need to be substituted for ear-pieces to help keep the glasses in place.
- Flexible hinges are advisable as they are less likely to break if handled roughly. Ask about a frame guarantee, which may be available on certain frames.
- Some frames can be fitted with clip-on sunglasses. These aren't essential, but sunglasses are advisable for all children on bright days.
How can I keep glasses on my child?
As a parent, it is important that you are positive about your child’s glasses. Without making a big fuss, gently encourage them to wear their glasses. Make sure you let them know how much they suit them.
If your child is an infant or toddler, distract them after you have put the glasses on. If they remove them, replace them immediately. If they remove them again, put the glasses aside for a short time and try again a bit later. Don’t give up! It can take a lot of patience and persistence to encourage a child to wear glasses.
Should my child wear glasses all the time?
Usually, when a child is prescribed glasses it's because they need to wear them all the time. Some children have ‘lazy eye’ (amblyopia). This is caused by poor development of the visual pathways to the brain because the image into the eye has been blurred. In this situation, it is essential your child wears their glasses all the time so the brain can learn to recognise clear images. To build vision in the ‘lazy’ eye, the ‘good’ eye may need to be patched (covered up) for part of each day.
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How do I care for my child's glasses?
Children should be taught to:
- remove their glasses using both hands without twisting the frame
- keep their glasses in a protective case and not put them face-down on any surface
- use water or liquid soap and a soft cloth to clean their lenses (avoid rough paper towels or tissues).
If the glasses become 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 (this is more frequently than for adults).
For further information and support talk to an optometrist or eye specialist.