Astigmatism is an refractive problem of the eye, which can be treated with laser eye surgery. Astigmatism can be corrected with LASEK (laser epithelial keratomileusis), LASIK (laser in situ keratectomy) and photorefractive keratectomy, which are discussed in this article.
Astigmatism is an refractive problem of the eye, that results from uneven or irregular curvature of the cornea or the lens. This condition is characterized by blurred vision. It is caused by the structural abnormalities of the cornea or the lens. As a result, light entering the eye does not refract correctly on the cornea and thereby causes blurred vision. This condition can be often treated with contact lenses and refractive eye surgery. Refractive eye surgery used for astigmatism can be of three types, LASIK, LASEK and photorefractive keratectomy. These are the laser eye surgeries, that are used for not only astigmatism, but for other refractive problems of the eyes as well. In this article, we are going to discuss what is astigmatism and the effectiveness of laser eye surgery for astigmatism treatment.
What is Astigmatism?
Generally, our eye is sphere shaped with a smooth and even curve. But, the cornea of the individuals with astigmatism is usually oval shaped or their lens do not have an even and perfect curvature. If there is a defect in the curvature of the cornea, light do not get refracted properly to create a clear image of the object. Similarly, when there is a problem with the curvature of the lens, clear images of the objects do not form in the retina. In both cases, the individual will experience distorted or blurred vision.
In astigmatism, the cornea or the lens can have irregular curvature, i.e. some areas can be flatter or steeper than other areas, instead of being even and smooth in all directions. The defect in the cornea can be caused by factors like, scarring, eye injury, infection and even certain types of eye surgery. Astigmatism can also be congenital, as some people can be found to born with a cornea with irregular curvature. Other possible causes include, premature birth and having a low body weight at birth. The problems with the lens of the eye on the other hand, can be associated with conditions like, high blood pressure.
Laser Eye Surgery for Astigmatism
Astigmatism can be corrected with the help of contact lenses. Rigid contact lenses, gas or oxygen permeable contact lenses and soft toric contact lenses are the commonly used contact lenses for astigmatism. If contact lenses fail to correct this refractive problem, then surgery can be required. There are basically three types of laser eye surgeries for this condition. Below here are some more information on these three types of laser eye surgery for astigmatism.
LASIK Surgery
LASIK is a very popular laser eye surgery for astigmatism and many other vision problems. LASIK surgery involves the use of a precision blade, known as microkeratome to make a thin and small incision in the outer layer or epithelium of the cornea. This epithelial flap is then lifted to gain access to the middle layer of the cornea. After this, an excimer laser is used to smoothen the cornea, so that it can refract light properly. Once reshaping is done, the epithelial flap is replaced and then covered with a contact lens. The healing time for LASIK eye surgery is much shorter than LASEK surgery. However, some antibiotic eye drops may need to be applied to prevent infection until the epithelium of the cornea heals completely. Find out some more information on LASIK eye surgery.
LASEK surgery
Laser-assisted subepithelial keratomileusis or LASEK is the surgery ideal for those with too thin or steep cornea, for which LASIK surgery is usually not carried out. In LASEK surgery, the thin epithelial layer of the cornea is preserved. The surgeon cuts the epithelium of the cornea with a fine blade, after which diluted alcohol solution is applied to the eye. This solution helps to loosen the edges of the epithelium or the outer layer of the cornea. Once the edges of the epithelium have loosened, the alcohol solution is removed from the eye. A tiny hoe is then used to lift and fold back this epithelial layer from the eye's surface, after which the surgeon applies laser beams with an excimer laser to reshape the surface of the cornea. Once reshaping is done, the epithelial flap is placed back on the surface of the eye. In this way, LASEK eye surgery can preserve the epithelial layer of the cornea and thus, reduces the chances of eye injury. However, this surgery may involve a longer healing time than LASIK surgery.
Photorefractive Keratectomy (PRK)
Photorefractive keratectomy is another laser corrective eye surgery, which involves the removal of the outer or surface layer of the cornea in order to change its curvature. After the outer layer or epithelium of cornea is removed, the curvature of the cornea is reshaped with the help of an excimer laser. This procedure is also known as surface ablation. This surgery often involves a longer healing time, which is its main disadvantage. The individuals with thin cornea are generally considered as eligible candidates for this laser eye surgery for astigmatism.
So, LASIK, LASEK, along with photorefractive keratectomy are the laser eye surgeries for astigmatism. For high astigmatism, many surgeons recommend wavefront laser surgery. This surgery is comparatively more expensive than the usual laser eye surgery. Astigmatism, especially high astigmatism can require greater accuracy, which wavefront laser surgery can ensure. However, your ophthalmologist or surgeon will be the best person to recommend which one would be the best for you.
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