Astigmatism is a common vision condition characterized by an imperfection in the curvature of the eye’s cornea or lens. Instead of a perfectly spherical shape, like a basketball, an eye with astigmatism has an irregular, more oval shape, similar to a football or the back of a spoon. This irregular curvature causes light rays entering the eye to bend unevenly, preventing them from focusing sharply on a single point on the retina. As a result, individuals experience blurred or distorted vision at all distances, along with potential symptoms like eyestrain and headaches. This article explores various methods available to manage and correct astigmatism, addressing the question of whether it can be permanently eliminated.
Correcting Astigmatism with Lenses
Non-surgical methods for managing astigmatism primarily involve prescription eyewear, such as glasses and contact lenses. Eyeglasses designed for astigmatism incorporate cylindrical lenses with different curvatures to counteract the eye’s uneven shape, bending light to focus it accurately on the retina.
Contact lenses specifically made for astigmatism are known as toric lenses. Unlike standard spherical contact lenses, toric lenses have a unique design with varying refractive powers across their surface, resembling a slice from the side of a doughnut. This specialized shape allows them to align with the specific angle of the astigmatism. To maintain proper orientation, toric lenses often feature design elements like thicker zones or weighted bases. While glasses and toric contact lenses effectively correct vision while worn, they do not alter the underlying shape of the eye and therefore offer a temporary solution for clear sight.
Surgical Solutions for Astigmatism
For individuals seeking a more lasting reduction or elimination of astigmatism, surgical options are available that aim to reshape the cornea. Laser-Assisted In Situ Keratomileusis (LASIK) is a refractive surgery that corrects astigmatism by using a laser to alter the corneal curvature. During LASIK, a surgeon creates a thin flap on the cornea, folds it back, and then uses an excimer laser to remove microscopic amounts of tissue from the underlying corneal layer. This reshaping makes the cornea more evenly rounded for improved light focus on the retina. After the laser treatment, the corneal flap is repositioned, and it naturally adheres without stitches.
Photorefractive Keratectomy (PRK) is another laser procedure. Unlike LASIK, PRK does not involve creating a corneal flap; instead, the outermost layer of the cornea, called the epithelium, is gently removed before the excimer laser reshapes the corneal surface. A protective bandage contact lens is then placed on the eye while the epithelium regrows over several days. PRK may be a suitable option for individuals with thinner corneas or those with active lifestyles where a corneal flap could be a concern.
Other surgical advancements include Small Incision Lenticule Extraction (SMILE), which uses a femtosecond laser to create and remove a small tissue piece (lenticule) within the cornea through a tiny incision, reshaping the cornea. This method avoids creating a large flap, potentially leading to less dry eye post-procedure. Implantable Collamer Lenses (ICLs) offer an alternative to laser vision correction, especially for those with higher prescriptions or thin corneas. An ICL is a biocompatible lens surgically implanted inside the eye, behind the iris and in front of the natural lens, to correct refractive errors, including astigmatism. This procedure does not permanently change the shape of the cornea.
Is Astigmatism Permanently Eliminated?
While surgical procedures like LASIK, PRK, and SMILE permanently alter the eye’s shape, the concept of “permanently eliminated” requires a nuanced understanding. The goal of these surgeries is to provide long-term astigmatism correction, allowing clear vision without glasses or contact lenses. However, the eye can undergo natural changes over time due to aging, hormonal factors, or the development of other eye conditions, which are not a recurrence of the original astigmatism.
In some cases, minor residual astigmatism might remain after surgery, or there could be a slight regression of the refractive error over many years. This regression is uncommon, with less than 5% of LASIK patients experiencing a return of astigmatism that may necessitate a secondary procedure or enhancement. Such changes are small and often do not require further treatment. “Getting rid of” astigmatism through surgery generally means achieving functional vision that significantly reduces or eliminates dependence on corrective eyewear, rather than erasing the initial irregularity or preventing future age-related eye changes.