What is astigmatism?
Astigmatism is very common, and there are different types of astigmatism, but for cataract surgery we usually refer to astigmatism of the cornea. The cornea acts like a lens, focusing light as it enters the eye. When the cornea is round, there is no astigmatism; however, many people have an oval-shaped cornea, which distorts the focus of light entering the eye. This abnormal focusing is called astigmatism, and it is usually correctable with glasses or contact lenses. Without correction, astigmatism results in blurred vision, often with ghosting or doubling of images.
Toric Intraocular Lenses (IOLs)
In the past, cataract surgery was not designed to correct astigmatism. However, more modern techniques allow us to reduce astigmatism during cataract surgery. Toric IOLs are similar to monofocal IOLs, except that toric IOLs also have a certain amount of astigmatism correction built-in. By reducing astigmatism, toric IOLs reduce dependence on glasses. By opting for a toric IOL, many patients with astigmatism will be able to see more clearly at distance without glasses, and use glasses just for reading. Patients who opt not to correct astigmatism will usually have to wear bifocals at all times after cataract surgery.
Cornea or Limbal Relaxing Incisions
Another method to correct astigmatism are corneal or limbal relaxing incisions (CRIs or LRIs). CRIs or LRIs are partial incisions made in the peripheral cornea. They are designed to reshape the cornea, from an oval to a round shape, thereby reducing astigmatism. CRIs or LRIs are quick to perform, and can be done at the same time as cataract surgery.
If you have astigmatism, ask our doctors whether you would be a candidate for CRIs or LRIs or a toric IOL.