Astigmatism 101
Astigmatism refers to blurred vision caused by an irregularly shaped cornea. The cornea is the clear front area of the eye which covers the iris. The iris is in front of the clouded natural lens being replaced by cataract surgery. The cornea should be perfectly round which then allows the eye to correctly focus on objects. In patients with astigmatism the cornea is a flattened oval and this causes focus issues which then translate into blurred vision.
Correcting astigmatism is done optically using glasses or contact lenses or through LASIK surgery. In cataract patients the correction can be made simultaneously using specially shaped Toric IOL lenses. These lenses are designed to correct focus imperfections caused by a flattened cornea, allowing patients to see clearly either at a distance or reading.
Toric lenses, however, are not multifocal. If Toric IOLs are implanted in both eyes for distance vision, then reading glasses would need to be used for near vision. Alternatively, one eye can be made better for distance while the other eye is better for near vision (“monovision”), thereby reducing the need for glasses.