Astigmatism is a common eye condition characterized by an irregular curvature of the cornea. This will blur vision much like myopia (nearsightedness), hyperopia (farsightedness), and presbyopia (the inability to focus on near objects and read up close after age forty).
A person's eye is naturally spherical in shape. Under normal circumstances, when light enters the eye, it refracts evenly, creating a clear image of the object. However, the eye of a person with astigmatism is shaped more like a football or the back of a spoon. For this person, when light enters the eye it is refracted more in one direction than the other, allowing only part of the object to be in focus at one time. Objects at any distance can appear blurry and wavy.
Astigmatism occurs in nearly everybody to some degree, but for significantly abnormal curvature, treatment is required. Astigmatism can be surgically corrected separately or at the time of cataract surgery with femtosecond laser cateract surgery, astigmatic keratotomy (AK) or with the implantation of a toric intraocular lens. It is also routinely corrected during laser vision correction surgery using the excimer laser when performing LASIK or PRK. As cataract surgery evolves now and in the future, more cataract patients are having their astigmatism corrected with Femtosecond Laser-assisted Cataract Surgery.
Laser Astigmatic Keratotomy (AK): This procedure is usually done at the beginning of a cataract operation and involves the laser making one or two additional incisions in the cornea at its steep axis to create a more spherical surface shape out of a previously football-shaped cornea. About 60% of Dr. Duffey's cataract patients have a large enough amount of astigmatism to benefit from Laser AK astigmatism correction. For these patients, it is either: 1) fix the astigmatism to minimize the need for glasses after surgery, or 2) wear glasses for distance and near after cataract surgery.