Astigmatism is a common vision disorder, but is not an eye disease. It’s a refractive error that occurs when your cornea (the surface of your eye) has an asymmetrical shape. Astigmatism is like nearsightedness and farsightedness; it can be corrected with prescription eyeglasses, astigmatism correction contact lenses or laser eye surgery.
A good analogy to describe the irregular shape of your eye in astigmatism is to think of sports: your cornea is shaped like a football instead of round like a baseball. Astigmatisms can also be slightly oblong like an egg. With astigmatism, your medians are misaligned. Think of meridians like a clock’s face. A line linking the 12 and 6 is one meridian, and a line from the 3 to the 9 is another meridian. The flattest and steepest meridians are principal meridians.
There are four main types of astigmatism:
- Myopic astigmatism occurs when one or both of the principal meridians of your eye are nearsighted.
- Hyperopic astigmatism occurs when one or both meridians are farsighted.
- Mixed astigmatism occurs when one principal meridian is farsighted and the other is nearsighted.
- Lenticular astigmatism occurs when your vision problems are caused by the shape of your lens, instead of your cornea.
Astigmatism Symptoms and Causes
Astigmatism typically causes blurred or distorted vision. Common symptoms of uncorrected astigmatism are headaches and eye strain, usually after reading or other prolonged tasks of intense focus. Another common symptom is squinting.
Astigmatism is classified as regular or irregular. A regular astigmatism has principal meridians that are 90 degrees apart and are perpendicular to one another. An irregular astigmatism occurs when the principal meridians are not perpendicular. Irregular astigmatism may result from an eye injury, keratoconus or from eye surgery. Most astigmatisms are regular.
Procedure for Correction
Different options are available to surgically correct astigmatism, depending on the eye condition you have:
- LASIK surgery uses a laser to reshape your cornea to correct the refractive error creating the astigmatism.
- Astigmatic Keratotomy involves making small incisions, called limbal relaxing incisions, into your cornea to make steep curves shallower to correct refractive disorders. Although astigmatic keratotomy is effective, laser surgery may be a better option for severe astigmatism.
- Astigmatism-Correcting Cataract Surgery is a procedure to remove your lens and replace it with an astigmatism-correcting intraocular lens (IOL). IOLs can potentially correct cataracts and astigmatism at the same time.
Procedures to Correct Astigmatism
Laser surgery procedures like LASIK, PRK and LASEK have very high success rates. The LASIK acronym stands for Laser Assisted In-Situ Keratomileusis, while LASEK means Laser Assisted Epithelial Keratomileusis. They’re designed to treat astigmatism, hyperopia (farsightedness) and myopia (nearsightedness). Each of these procedures enables you to live without glasses or contacts.
LASIK and LASEK surgeries differ in how your eye surgeon reaches the mid-layer of your cornea (or stroma) to reshape it. In LASIK eye surgery, the doctor uses a femtosecond laser to create a corneal flap to access the cornea underneath. In LASEK, the surgeon removes the outer layer of the cornea before reshaping the stroma. The outer layer is replaced and allowed to heal and re-grow on its own.
Risks of Surgical Options
Loss of vision and other sight-threatening complications from LASIK are extremely rare. Side effects from laser eye surgery can be typically resolved with medical treatment or additional surgery.
Laser surgery has potential risks, like any other surgery, and there are side effects you should be aware of before undergoing the treatment. One way to avoid these complications and risks is to choose an experienced, skilled laser eye surgeon.
Your Options Explored
The first step in LASIK surgery is to determine if you are a good candidate for corrective vision surgery. Your eye doctor takes you through a series of diagnostic eye exams to determine your suitability for laser eye surgery. These tests determine the thickness and shape of your cornea, your pupil size and your refractive errors. A medical history reveals your general health and any medications you’re taking.
Even if you aren’t a suitable candidate for LASIK, you may qualify for another type of corrective vision surgery such as PRK, LASEK or permanent lenses that are placed in your eyes. Certain anatomical factors and conditions increase the risk of being unsuitable for a LASIK surgery, such as:
- Large pupils
- Corneas that are too thin or irregular
- Unstable prescriptions
- Extreme refractive error
- Dry eyes
- Advanced age
- Active autoimmune or certain degenerative disorders
LASIK Side Effects and Complications
Millions of Americans have had the LASIK procedure over the last 20 years. Of that number, LASIK surgeons report that serious risks from surgery are below one percent, according to the Boxer Wachler Vision Institute.
One of the most common side effects is temporary discomfort and vision disturbance. Mild irritation and light sensitivity is normal and expected in the first few days following LASIK surgery. Within the first few weeks to months, you may also see halos, starbursts or glare in dimly lit conditions, especially at night. You also might experience dry eye symptoms, reduced sharpness of vision and hazy vision (all symptoms of dry eye). In almost every case, these issues are temporary and clear up for good within three to six months.
Recovery from Various Astigmatism Corrections
Recovery time is different between LASIK and LASEK surgeries. If you have a LASIK procedure, you can expect to recover significantly faster than if you have a LASEK procedure. In LASIK, you can return to functional vision within 48 hours of surgery. You’ll feel discomfort only a few hours, and steroid eye drops are required only for about a week after surgery. The LASEK recovery time, on the other hand, is one to two weeks after surgery for functional vision. You’ll need steroid eye drops for several weeks.
Astigmatism causes the focal point of light to focus in front of the retina or behind it, causing nearsightedness or farsightedness. The recovery time for most astigmatism corrective surgeries ranges from just a few days to several weeks. Talk to your ophthalmologist about setting up an appointment to discuss your options and suitability for the various astigmatism corrections available to improve your vision.
Important Reminder: This information is only intended to provide guidance, not a definitive medical advice. Please consult eye doctor about your specific condition. Only a trained, experienced board certified eye doctor can determine an accurate diagnosis and proper treatment.
Do you have any questions about Astigmatism? Would like to schedule an appointment with an internationally recognized, top NYC Ophthalmologist or Optometrist, Dr. Saba khodadadian of Manhattan Eye Specialists, please contact our office for consultation with NYC Eye doctor.
Dr. Saba Khodadadian, Optometrist (NYC Eye Doctor)
New York, NY 10010
(Between Madison Ave & Park Ave)
☎ (212) 533-4821