Cataracts and astigmatism are common eye conditions that affect vision. While cataracts involve the clouding of the eye’s natural lens, astigmatism relates to an imperfection in the eye’s curvature. For individuals with both conditions, a common question is how cataract surgery impacts existing astigmatism. Understanding both conditions and their management during and after surgery is important.
Understanding Astigmatism and Cataracts
Astigmatism is a refractive error that occurs when the eye’s cornea, the clear front surface, or the lens inside the eye has mismatched curves. Unlike a uniformly round shape, the cornea or lens is shaped more like a football. This irregular shape causes light rays entering the eye to bend unevenly, leading to blurred or distorted vision at all distances. Astigmatism can be present from birth or develop over time.
Cataracts involve a clouding of the eye’s natural lens. This clouding happens as proteins within the lens break down, making vision blurry, hazy, or less colorful. Cataracts commonly develop with age, though vision problems may not be noticeable for years. Both astigmatism and cataracts can cause blurry vision, but they affect different parts of the eye and require distinct treatments.
Astigmatism Changes After Cataract Surgery
Cataract surgery removes the cloudy natural lens and replaces it with a clear artificial IOL. Astigmatism generally does not worsen after cataract surgery; it can often be improved or corrected. However, some patients might notice their astigmatism more acutely after surgery because removing the cataract unmasks pre-existing astigmatism previously obscured by the cloudy lens.
Surgically induced astigmatism (SIA) can occur from small corneal incisions made during the procedure. This can temporarily alter the corneal curvature. SIA amount depends on incision size, location, and healing. While SIA is typically minor and often resolves as the eye heals, significant induced astigmatism can rarely occur due to unusual healing or complications. Precise pre-operative measurements minimize these changes.
Addressing Astigmatism During Cataract Surgery
Cataract surgery advances allow for astigmatism correction or minimization during the procedure. One common approach uses Toric Intraocular Lenses (IOLs). These artificial lenses replace the cloudy natural lens and have different powers in different meridians to correct existing astigmatism. Surgeons precisely align the toric IOL to counteract the patient’s corneal astigmatism.
Another technique for astigmatism during cataract surgery involves Limbal Relaxing Incisions (LRIs). These small, precise incisions are made at the corneal edge, near the limbus. LRIs work by relaxing the steeper curvature of the cornea, making it more spherical, reducing astigmatism. This procedure can be performed with cataract surgery to enhance visual outcomes, particularly for mild to moderate astigmatism. Options are chosen in consultation with the surgeon based on individual eye measurements and visual needs.
Managing Astigmatism After Cataract Surgery
Even with advanced techniques, some patients experience residual astigmatism after cataract surgery. For mild cases, prescription glasses or contact lenses are the most common solution for clear vision. These options effectively compensate for remaining astigmatism, allowing optimal visual acuity.
For those seeking to reduce dependence on glasses or contacts, enhancement procedures are available. Laser vision correction (LASIK or PRK) can be performed after the eye heals from cataract surgery, typically after three to six months. These procedures reshape the cornea to correct remaining refractive errors, including astigmatism, for a more precise visual outcome. Management strategy depends on residual astigmatism, patient visual goals, and eye care professional evaluation.