What is astigmatism?
Astigmatism is a condition where light entering the eye is focussed at two different points on the retina. This is commonly caused by uneven curvature of the cornea, but can also occur due to uneven curvature of the lens within the eye. These curvatures are often simply described as being 'football' or 'egg' shaped in appearance. As a result of these uneven curvatures of the eye, both distance and near vision is blurred. The unique blur created is asymmetric in nature, meaning that some directions of an image are more blurred than others.
How can I tell if my child may have astigmatism?
A complete eye examination is the only sure way of determining whether your child's vision is normal. Some clues to astigmatism in a child are screwing up eyes to compensate for blurred vision, and headaches when concentrating on reading or watching TV.
How is astigmatism corrected?
Spectacles and contact lenses (hard and soft) can correct astigmatism. Thinner spectacle lenses, also known as hi-index lenses, are available to improve the cosmetic appearance of higher powered prescriptions. Many disposable contact lenses are available in a wide range of parameters meaning that the majority of prescriptions can be corrected accurately. Also laser corrective surgery can be considered to correct astigmatism once the eye has stopped growing, typically from the age of 21 onwards. Occassionally, correction of astigmatism for the first time can cause change in the apparent size and shape of objects and may affect judgement of distance. A patient may feel taller or shorter, or walls may appear to slope and floors curve. In most cases, adjustment to these side effects takes only a week or so. Astigmatism correction may involve a compromise between optimal clarity and visual discomfort.
Recommendations for astigmatism
It is important for your child to have a full eye examination by the age 3. Upon commencing school, the Optometrists Association Australia recommends that all children be examined regularly during their primary and secondary school years. A balanced lifestyle incorporating outdoor play and regular breaks from concentrated near tasks such as computer use, can help maintain efficient vision in children and young adults. Preventing astigmatism is not generally possible, as it is either an inherited trait, or a normal variation accompanying development.