Astigmatism | Kansas City Eye Surgeons
Most people have heard the term astigmatism, but many patients are surprised when it is used to describe their own eyes. At Cavanaugh Eye Center, we often hear that patients have been told they were poor candidates for vision correction surgery due to their astigmatism. Thankfully, with advances in technology and an experienced surgeon, almost all levels of astigmatism can be corrected.
What is Astigmatism?
First, it is important to understand a few basic principles of the eye to understand astigmatism. The cornea is the clear front window to the eye and focuses light that enters the eye on the retina.
Imagine the eye as a camera:
The cornea is like the focusing lenses of a camera.
The retina is similar to the film (of older cameras) or the image process chip (of modern cameras).
Astigmatism is a condition where the cornea is not perfectly round in shape or is “out of round.” When the cornea’s contour is not a perfect sphere, light rays do not pass cleanly through the tissue and light ends up focusing at different locations on the retina. This causes images to be out of focus. Just like the blurry image that results when there is a smudge on your camera lens.
Envision you are gently holding a perfectly round pliable ball between your thumb and pointer finger. If you squeeze the ball with your fingers, its shape would change and become oval or out of round. That is basically what a cornea with astigmatism looks like.
What Causes Astigmatism?
Astigmatism is a common condition, as no one’s eyes are as round as a perfect sphere. Genetics plays a big factor in astigmatism and it’s often present at birth; in fact, most infants have a moderate amount of astigmatism that improves over time as they develop. Additionally, astigmatism may develop later in life or occur as a result of an eye injury or disease. A common misconception is that it is caused by poor vision habits, such as reading in the dark or sitting close to the TV; however, there is no evidence for this. Astigmatism is simply an imperfection in the curvature of the cornea—it can worsen or improve over time just like other vision conditions, but not because of someone’s vision habits.
Instead of focusing at a single point, light rays passing through an astigmatic cornea will focus at two or more locations. This results in blurred vision and ghost images around objects. Unlike farsighted or nearsightedness, astigmatism can affect your vision at any distance, near or far.
Treatment for Astigmatism
Traditionally, astigmatism had been treated with glasses, gas permeable contacts, or toric soft contact lenses. If you desire the most freedom from glasses or contacts at any distance, it is imperative that your astigmatism be surgically corrected. In order for light to focus precisely, the cornea needs to be as round as possible. Even high levels of astigmatism can be corrected surgically.
Here are the different surgical options for astigmatism correction:
Years ago the correction of astigmatism was one of the greatest hurdles to an excellent LASIK result. Now, with advances in LASIK such as precise eye-tracking technology and topography-guided treatment plans, LASIK has become routine and an excellent option when combating astigmatism. Additionally, our advanced Alcon EX500 laser can treat higher levels of astigmatism than the older generation excimer lasers while simultaneously correcting other flaws in the cornea, yielding excellent visual clarity and comfort.
Learn more about LASIK here.
STAAR Visian Toric ICL
The STAAR Visian Toric ICL (Implantable Collamer Lens) is a great option for patients who are not candidates for laser refractive surgery due to high levels of nearsightedness, thin corneas, or extreme dry eyes. Until recently, STAAR ICL patients who also had moderate to high levels of astigmatism were not good candidates for ICL implantation. The STAAR Visian Toric ICL is now available and provides excellent visual outcomes for these patients.
Learn more about Visian ICL technology here.
Advanced surface ablation (ASA), also called photorefractive keratectomy (PRK), is a proven LASIK alternative that corrects astigmatism, nearsightedness, and farsightedness. Like LASIK, ASA/PRK reshapes the cornea to dramatically improve vision. The two procedures are similar with comparable long-term vision outcomes. The main difference is that ASA/PRK does not utilize the creation of a flap in the top layer of the cornea that is routine with LASIK.
Learn more about ASA/PRK here.
Intraocular Lens Implants (IOLs)
Toric IOLs have your astigmatism power incorporated into the lens implant optic and provide a precise way to reduce or eliminate astigmatism. These IOLs are for cataract and refractive lens exchange patients with pre-existing astigmatism who want spectacle reduction for distance vision or a reduction in the thickness of glasses. Exciting advancements in IOL technology have produced multifocus toric IOLs that combine astigmatism and presbyopia (loss of reading vision over age 40) correction into the same lens implant. This provides an expanded range of vision from distance to near for those who need correction from a toric lens implant but desire greater freedom from reading glasses. One example is the PanOptix Toric Multifocal IOL which uses new technology to achieve trifocal vision for all three points of focus: distance, intermediate, and near while simultaneously correcting astigmatism.
Limbal Relaxing Incisions (LRIs)
LRIs correct astigmatism by using small incisions to relax the tension in the cornea that causes it to be out of round. Incisions are placed near the junction of the white and colored part of the eye (the limbus), they expand the cornea and effectively convert the oval cornea to a sphere, thereby correcting the astigmatism. LRIs can be done as a stand-alone procedure or can be performed in conjunction with cataract and/or refractive lens implant surgery.
Learn more about IOLs and LRIs here.
Contact Cavanaugh Eye Center for Astigmatism Treatment
Are you tired of your astigmatism holding you back? We understand how problematic uncorrected astigmatism can be for patients and want to help give you the visual freedom you deserve. Dr. Cavanaugh, Dr. Jaynes, and the Cavanaugh Eye Center staff have the experience you want in your eye care team—from your surgery to your post-operative care, Cavanaugh Eye Center has got you covered.