Astigmatism occurs when the front of your eye (cornea) is slightly irregular in shape, not perfectly round – the surface of a rugby ball. This affects the the way light is focused on the retina. Vision will be blurred at all distances. (i.e. the eye has different focal points in different places). Sometimes it is the result of an irregularly shaped lens, which is located behind the cornea: this is called lenticular astigmatism.
Astigmatism is not a disease. It is a vision condition that is quite common. The causes of this irregular shape of the cornea are varied. In some cases, it may be hereditary or it may result from such factors as pressure of the eyelids on the cornea, or from inherent weakness of the corneal structure. Those with astigmatism may experience headaches, eye strain, fatigue of blurred vision.