When the natural crystalline lens of the eye is removed during cataract surgery, it can be replaced with a toric intraocular lens (IOL) to correct astigmatism. Toric intraocular lenses are not multifocal lenses, but they can provide significantly improved vision for people suffering from moderate to high astigmatism.
Astigmatism is the result of a slight dysfunction in how the eye works: the cornea and/or lens are oblong instead of spherical. Because of the oblong shape of the cornea and/or lens, light passing through the cornea and lens at different positions have different focal points, which can lead to blurry vision at all distances. Astigmatism can be corrected with glasses or contact lenses, and some degree of corneal astigmatism can be corrected with LASIK.
If you have minor astigmatism, or are happy using contact lenses to correct your astigmatism, you may not want or need to use toric intraocular lenses. You should consult with your ophthalmologist to determine the level of your astigmatism and how your prescription may be affected by cataract surgery before deciding whether or not toric intraocular lenses should be used to correct your astigmatism.
Another option traditionally used for correcting astigmatism during cataract surgery is the limbal relaxing incisions, which are incisions in the cornea to reshape it. Some research indicates that toric intraocular lenses give better corrected vision. According to other research, both treatments give similar quality of results, but the use of toric intraocular lenses seems to give more stable long-term results. For patients with severe astigmatism, toric intraocular lenses can be combined with limbal relaxing incisions to give the best possible results.
Most of the risks involved in using a toric intraocular lens are common to all cataract surgeries. These include infection, swelling or clouding in the eye, retinal detachment, and macular edema. Another risk is that the lens may become detached following surgery and require repositioning.
Finally, if the correction power of the toric intraocular lens is miscalculated or the lens is misaligned during surgery, additional surgery may be required to achieve the best results.
If you would like to learn whether toric intraocular lenses might be right for you after cataract surgery, find a local ophthalmologist who can discuss your options and find the solution that best matches your lifestyle and vision needs.