What is Astigmatism?
Astigmatism is a common optical condition caused by the shape of the front surface of the eye.
An eye with no astigmatism is perfectly spherical in shape, like a marble. An astigmatic eye has a distorted shape, slightly like a football or grape. This can cause the image formed at the back of the eye to be distorted. Most people have a low degree of this condition originating in either the cornea or the lens inside the eye. Low degrees can slightly distort your vision, for example a ‘C’ may look like an ‘O’ or a ‘G’. You may also experience strain or discomfort with visual concentration. In higher degrees, astigmatism can cause images at all distances to be distorted or blurred.
Thankfully, it is easily corrected with spectacles or contact lenses.
Usually, astigmatism stays relatively stable throughout life, however there are some conditions that continue to progress. The most common one is keratoconus. Keratoconus is caused by a thinning of the fornt surface of the eye, the cornea. This thinning causes the cornea to rapidly change shape creating high degrees of astigmatism and distortion. People with keratoconus may need hard contact lenses to obtain clear vision, or may need a surgical procedure to stabilise their cornea. Research has shown that eye rubbing (usually due to allergies like hayfever) can progress this condition.
Squinting to see, complaining of glare or getting frontal tension headaches may indicate you have this condition in your optical system.