Myopia (Shortsightedness)
In order to see clearly, light rays from an object must focus onto the inner back layer of the eye. The eye works like a camera. In myopic eye the focusing power of the eye is too strong where the light rays focus in front of the retina. Objects in the distance appear blurry and as they get closer to the eye, are seen more clearly.
What is myopia?
In order to see clearly, light rays from an object must focus onto the inner back layer of the eye (the eye works like a camera). It has an opening at the front (the pupil), a focusing mechanism (the cornea and crystalline lens) and a light-sensing portion at the back (the retina). If light rays are not focused on the retina, a refractive error is present.
In a myopic eye, the focusing power of the eye is too strong where the light rays focus in front of the retina. Objects in the distance appear blurry and as they get closer to the eye, are seen more clearly.
What causes myopia?
This condition may be inherited or associated with premature birth and can occur at any age. Increased near visual activities are known to be associated with the development or progression of myopia.
The prevalence of myopia is about 20% in children but much higher in Asian ethnic groups (around 50-70%.). Myopia is less common among Maori and Pacifica children. Myopia usually progresses yearly and stabilises by the late teens to early twenties.
How is myopia treated?
There is currently no widely accepted treatment to stop the progression of myopia. Weak atropine drops have been effective in slowing down myopia progression in some international studies. Some recent epidemiological data suggests that more time spent outdoors was associated with less myopic progression.
Most children with myopia will need to wear corrective spectacles/contact lenses for better vision. Laser refractive surgery is usually contraindicated in children because of the change of focus with age. This can be considered after 20 years of age when the refractive power stabilises.
Educational Implications
Behaviours or conditions that might indicate myopia
- Blurry or fuzzy vision when viewing distant information.
- Partially closing or squinting eyes when viewing distant information.
- Experiencing headaches caused by eyestrain.
- Wanting to move or sit closer to visual information (television, computer screen, mat area in the classroom).
- Blinking excessively and/or rubbing eyes frequently.
- Creating a ‘pinhole’ or a tiny space with hands or fingers when viewing distant information.
What to do
- The young person should visit an optometrist to determine diagnosis and to be fitted for glasses with corrective lenses or contact lenses.
- When using glasses with corrective lenses or contact lenses, persevere. Try to engage the young person with something interesting and diverting to become more accustomed with the corrective view through the lenses when looking at distant information.
- If the young person finds it challenging to wear glasses or contact lenses, review whether the issue is one of comfort or whether the lenses may no longer be accurate. When a young person chooses not to wear prescription glasses and/or contact lenses and comfort has been ruled out, it might indicate that the prescription is no longer helpful and may need to be reviewed or that the young person is not experiencing any consistent, obvious and functional benefit from the correct prescription lenses and a review may be required.
- If the child’s vision fails to improve with correcting glasses then the child should be reviewed by an ophthalmologist to make sure the diagnosis is correct.
- If the young person wears glasses, remember that the corrective lenses are for distance viewing. The young person may look over the frames or may choose not to wear the glasses when engaged in near tasks such as reading. The young person may have better clarity of vision in near space without looking through the lenses. However, when the young person is expected to view distant information, glasses will be beneficial and necessary for better clarity of vision if the prescription is accurate.