What is astigmatism and how can it be corrected?
A person with astigmatism has an unevenly curved cornea - the clear covering of the front of the eye - or unevenly curved lens inside their eye, shaped more like a rugby ball than a football.Imagine a rugby ball sliced in half along its longest part. The cut surface is an oval shape, and you place the cut surface flat on a table. Imagine you are looking at it from its pointed end - the sides curve up steeply. Imagine you are looking at it from halfway between the two pointed ends - the sides curve much less steeply. This is an exaggerated version of the shape of the astigmatic cornea. It is corrected by spectacles with a cylinder shape built into the lenses at a certain angle. Contact lenses can also correct astigmatism - mild astigmatism can be corrected by an ordinary gas-permeable lens. Those who prefer a soft lens or have higher amounts of astigmatism can use specially designed 'toric' soft lenses.