Astigmatism is a sight alteration produced by a focussing disorder, which only affects a certain plane. Its most immediate consequence is going to be the perception of distorted images.
In an eye that suffers from astigmatism, depending from which plane the light cuts through the cornea, this will be focussed either in front of or behind the retina, in function of the size of the irregularity. This gives rise to that distorted sight that is so characteristic. Similar to mirrors at a fairground.
This irregularity is usually genetically pre-determined. Apart from the previously mentioned distorted images, its symptoms include frontal headaches, and carrying the head slightly inclined seeking more favourable angles. Astigmatism can be treated using glasses, contact lenses or with intraocular surgery, however the method that gives greatest visual freedom with minimal risks during the operation, is laser correction.