Astigmatism and Cataracts – James S. Lewis, MD
Serving Philadelphia, Northeast Philadelphia, Phoenixville, Conshohocken, Main Line and King of Prussia
Almost half of the eyeglass and contact lens wearing patients have been told they have astigmatism. It is rarely explained well. Astigmatism is the lack of radial symmetry of the eye’s visual system. That means an optical solution (glasses, contacts, LASIK, cataract surgery) must bend light differently in each meridian to allow parallel light from a distant object to focus perfectly on the fovea, the visual acuity center of the retina. In other words, a perfectly “spherical” system only requires a simple, spherical pair of glasses, contact lenses, LASIK surgery or Cataract Implants. The “astigmats”, however, need a more sophisticated solution.
During cataract surgery the cloudy natural lens is removed and replaced with an implant. Most astigmatism is produced by asymmetric curvature of the cornea and the natural lens. Once the lens is removed only the corneal astigmatism remains. Special implants can be used to eliminate the residual corneal astigmatism. There are two astigmatism-correcting implants on the market, one by Staar Surgical and the other by Alcon. Both are excellent and extremely effective for reducing or eliminating astigmatism following cataract surgery.
Sometimes all of a Philadelphia cataract patient’s astigmatism is produced by the natural lens. When this happens cataract removal alone removes all astigmatism so a Toric implant is not needed. Sometimes a patient with no pre-operative astigmatism will manifest corneal astigmatism after cataract surgery. Those patients can undergo special procedures to resolve their astigmatism.
In all of our cases, we aim to reduce the patient’s astigmatism following cataract surgery. Sometimes that is done with special relaxing corneal incisions for smaller amounts of astigmatism. Others require an Toric Implant. Still others require both modalities. There is an additional cost for some Toric IOLs and we will tell you if they are recommended in your case.
Intraocular Lens (IOL) introduction
Rarely, large degrees of astigmatism remain after cataract surgery. When this happens we have the luxury of an excimer laser in-house. A LASIK-like correction can be performed following cataract surgery if the patient does not have adequate uncorrected distance visual acuity. Sometimes, this too incurs an additional cost.
Irregular astigmatism, a more rare type of astigmatism often associated with corneal disease, trauma, or hard/RGP lens wear, does not respond to relaxing incisions, LASIK and Toric implants. These patients still benefit from cataract surgery but require a customized approach to their astigmatism.
Astigmatism correction with cataract surgery, either by relaxing limbal incisions, toric implants, or LASIK is an important advance in the eye surgery. As Corneal Specialists, we pride ourselves in our success with these cases.
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