What is Astigmatism?
Astigmatism is a condition where the surface of the eye is not perfectly shaped and is more steeply curved in one direction than another. This is a refractive problem where the image that the eye sees is out of focus and generally glasses are required to correct this and allow good vision. Standard monofocal lens implants correct for near-sightedness or far-sightedness but not for astigmatism. If a patient with astigmatism has cataract surgery with a standard monofocal lens implant instead of a toric lens, full-time glasses wear will be needed to achieve their best vision at all distances.
Astigmatism can often be corrected during cataract surgery by using a toric lens implant that has astigmatism correction built into it. This works very well and allows the patient significant freedom from glasses. Good distance vision is usually targeted and glasses are still needed for intermediate and near work afterwards. Many patients choosing toric lenses are able to drive and see distance without glasses. However, glasses may still be required to achieve their BEST vision even at distance. Toric lenses are a very good option for most patients with astigmatism but cannot be used in some patients if their astigmatism is severe or irregular. There is no real downside to these lenses other than the added cost.
Important Note:
Lens implant calculations are very good but not perfect. In some patients, the implant power will not turn out exactly as targeted. These patients may need glasses to achieve their best vision and will not be as independent of glasses as desired. Please remember that the primary reason for cataract surgery is to remove the cloudy lens and restore good vision again. Becoming less dependent on glasses is a secondary goal. At the North Idaho Eye Institute, our surgical and lens implant outcomes are carefully tracked and match the best published outcomes in the country but we cannot guarantee your final vision level or that you will be glasses free.
