Do you know why you wear glasses? Is it because you are short-sighted (or was it long-sighted?)? Our next few issues will cover the many eye conditions that are treated with glasses, including myopia, hypermetropia, astigmatism and presbyopia, enabling you to answer with confidence when you are asked "Why do you need glasses?".

Myopia (Short Sightedness)

Myopia or short-sightedness is a vision problem experienced by almost one-third of the population of Australia. It is the inability of a person to see distant objects clearly; hence, one sees clearly at short distances - short-sighted.

For clear vision, the cornea and the lens must properly focus (or refract) light onto the retina. (Figure 1) If the length or the shape of the eye is not ideal, the light may get focused too early (myopia) leaving a blurred image on the retina. (Figure 2)

The exact cause of myopia is still uncertain. However, myopia has been strongly linked to improper reading habits, e.g. working at close distances for long periods of time and/or working at close distances in poor lighting conditions. Myopia has also been linked to genetics - it has been proven that the risk of a child developing myopia increases significantly if one or both parents are myopic.

The most common symptoms of myopia are problems with seeing the board at school, as myopia is often discovered in school children. Children often find themselves having to squint to see more clearly in the distance. This causes eyestrain and can also lead to headaches.

Treatment

An optometrist or ophthalmologist can easily diagnose myopia. Once diagnosed, the most common treatment for myopia is Glasses, which allow the light to be focused properly on the retina. (Figure 3) Proper focusing can also be obtained using Contact Lenses. (Figures 4 and 5) Laser Surgery is another option, which obviates the need for glasses and contact lenses. Another less common treatment options include, Orthokeratology, which involves wearing retainer contact lenses that slowly reshape the cornea to correct the myopia over a period of time.