Astigmatism is a common refractive error that results from an imperfection in the eye's curvature. In normal eyes, the cornea (the front part of the eye's surface) and the lens are smooth and evenly shaped in all directions. With astigmatism, the cornea or lens is irregularly shaped in some areas, causing blurred vision. Astigmatism is not an eye disease; it is simply a variation in the way the eye is shaped. A person can experience moderate to severe astigmatism depending on how many corneal or lens disturbances are present. Read on to learn more about the causes of astigmatism, its symptoms, and diagnosis.
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The most common symptom of astigmatism is blurred vision at any distance. People with astigmatism often experience distortions of vertical, horizontal, or diagonal lines, as well as frequent headaches and fatigue, squinting, eye discomfort, and irritation. These symptoms are not exclusive to astigmatism and will vary depending on whether the patient has mild, moderate, or severe astigmatism. If you experience any of these symptoms, you should contact a qualified ophthalmologist for a comprehensive eye examination.
Causes of Astigmatism
In the human eye, the cornea focuses images by refracting incoming light onto the retina (back of the eye). In the ideally-shaped eye, the cornea has a smooth, even curvature and is shaped like a round ball. With astigmatism, the cornea is shaped more like an oval, or football, causing light to scatter as it passes through. The result is a blurred image on the retina, making it difficult for people with astigmatism to see clearly at any distance.
Contrary to common belief, reading in poor light, squinting, or sitting too close to the television are not causes of astigmatism. Astigmatism is usually present from birth and can either stay the same or worsen over time. Eye injury, disease, or surgery can also be causes of astigmatism.
Astigmatism is usually diagnosed during routine eye exams. wherein your ophthalmologist will check your eye's refraction (ability to properly focus light rays on the retina) and visual acuity using a standard eye chart. The eye's refraction can be measured in a number of ways; some doctors will simply ask a series of questions about your current vision and conduct a visual acuity test, while others will use a keratometer or keratoscope to assess the curvature of your cornea and determine the presence of moderate or severe astigmatism.
Moderate to Severe Astigmatism
Many experts believe that all people are born with a degree of astigmatism that may worsen or stay the same throughout their lifetime. For most people, the degree of astigmatism experienced is so mild that it does not require corrective lenses. However, for those with moderate to severe astigmatism, eyeglasses or contact lenses must be worn unless their vision is corrected with refractive surgery.
Degree of Refractive Error
The term refractive error refers to the degree to which images received through the eye's cornea and lens are not focused on the retina. In other words, it is the degree of "blurriness" that a person experiences when trying to focus on images at varying distances. The numbers on a person's eyeglass or contact prescription reflect this measurement. With astigmatism, the degree of refractive error is noted under "C," or "cylinder," which measures the eye's irregular curvature. A person's prescription can vary greatly depending on whether he or she has moderate or severe astigmatism, and it must remain stable before LASIK or other refractive surgery can be performed.
Contact an Ophthalmologist for an Eye Exam
If you experience any of the symptoms of moderate or severe astigmatism, it is important that you schedule a comprehensive eye exam as soon as possible. A qualified ophthalmologist can explain in detail the varying degrees, symptoms, and causes of astigmatism and provide you with an appropriate prescription.
There are a number of options for patients seeking effective astigmatism treatment, from time-tested eyeglasses to the latest in laser technology. Choosing the right treatment for you will depend on a number of factors, including your lifestyle, medical history, and degree of refractive error.
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Glasses and Contact Lenses
Before the advent of refractive surgery, eyeglasses and contact lenses, were the only way to correct astigmatism, and many people still prefer them. Eyeglasses are a reliable astigmatism treatment that comfortably correct for the cornea's irregular curve. Contact lenses are another option and can vary greatly in type. Hard, soft, extended wear, disposable, rigid gas permeable, and bifocal contact lenses are all appropriate choices for astigmatism treatment.
LASIK which stands for "Laser-Assisted In Situ Keratomileusis," is an astigmatism treatment that uses a cold-beam excimer laser to reshape the cornea so it can properly focus images on the retina. The LASIK procedure involves cutting a small flap in the cornea and moving it out of the way before reshaping the underlying tissue. The cornea heals quickly, and many patients notice a significant improvement in vision within the first day of recovery. Because of its short recovery time and convenience (it is an outpatient procedure, and usually takes only 10-15 minutes), LASIK is the most frequently performed of all refractive surgeries.
Another innovation in astigmatism treatment is custom LASIK surgery, or Wavefront™ LASIK, which takes three-dimensional measurements of how your eyes process images and uses them to guide the laser during surgery. This method is much more precise than traditional LASIK and makes for a more accurate astigmatism treatment than glasses or contacts.
The team of doctors at Clinica Refractiva Navex have more than 15 years of experience with LASIK surgery (More than 10,000 surgeries successfully done). They are pioneers in Costa Rica with this procedure and use state of the art technology. They have continuing education program and give top of the line maintenance to their excimer laser. For more information keep browsing our pages or talk to an skilled and experienced eye surgeon for more information today.
PRK which stands for "Photorefractive Keratectomy," was the first form of refractive surgery available in the United States and is still a preferred astigmatism treatment for patients with large pupils or very thin corneas. The PRK process involves removing the epithelium (outer layer of the cornea) and using a cool ultraviolet light to reshape the surface of the cornea. This method is less invasive than LASIK because it does not actually reshape the cornea's interior. It does require a longer recovery time, however, but for those willing to make the commitment, PRK is an excellent and time-tested astigmatism treatment.
Although the term LASEK sounds a lot like "LASIK," the procedure is actually more similar to PRK. This form of astigmatism treatment is appropriate for patients whose corneas are too thin or too flat for traditional refractive surgery. In LASEK, the epithelium, or outer layer of the cornea, is cut using a tiny blade called a trephine. An alcohol solution is then applied to loosen the epithelial cells. The epithelial flap remains pulled back during surgery until the cornea has been reshaped. Unlike in PRK, the corneal flap is never fully removed. Your doctor may recommend LASEK as an alternative astigmatism treatment to LASIK if your corneas are very thin or if you have dry eyes.
Epi-LASIK is a form of astigmatism treatment that combines the advantages of LASIK and LASEK. Epi-LASIK differs from these two treatments, though, in a number of ways. First, the surgeon uses a blunt, plastic blade, called an epithelial separator, to pull back the corneal flap. This eliminates the need for alcohol, which is used in LASEK to loosen the epithelium. After the corneal tissue has been reshaped, the flap is placed back onto the surface of the eye. Along with LASEK and PRK, Epi-LASIK is an appropriate astigmatism treatment for patients whose corneas are very thin.
Unlike LASIK or other refractive surgeries that reshape the cornea, a lensectomy is an astigmatism treatment that actually replaces the eye's natural lens. Often, a person's lens is either too strong or too weak for proper vision and can be replaced with an artificial one. With traditional lens implants, patients normally achieve good distance vision but need glasses for reading and seeing up close. New implantable pseudophakic intraocular lenses, however, allow patients to see clearly at all distances.
Talk to a Specialist to Discuss Your Treatment Options
To discuss which type of astigmatism treatment may be right for you, speak with your family doctor. It is also a good idea to speak with a qualified ophthalmologist or LASIK surgeon, as he or she can give you detailed information on the many treatment options available.
The team of doctors at Clinica Refractiva Navex have more than 15 years of experience with LASIK surgery (More than 10,000 surgeries successfully done). They are pioneers in Costa Rica with this procedure and use state of the art technology. They have continuing education program and give top of the line maintenance to their excimer laser. For more information browse in our LASIK page or talk to an skilled and experienced eye surgeon today.