Astigmatism is a type of refractive error of the eye. Refractive errors cause blurred vision and are the most common reason why a person goes to see an eye professional.
Other types of refractive errors are:
Causes, incidence, and risk factorsPeople are able to see because the front part of the eye is able to bend (refract) light and point it to the back surface of the eye, called the retina.
Changes in the length of the eye, or the shape of either the lens or the cornea make it more difficult for the eyes to focus light. If the light rays are not clearly focused on the retina, the images you see may be blurry.
With astigmatism, the cornea (the clear tissue covering the front of the eye) is abnormally curved, causing vision to be out of focus.
The cause of astigmatism is unknown. It is usually present from birth, and often occurs together with nearsightedness or farsightedness.
Astigmatism is very common. It sometimes occurs after certain types of eye surgery, such as cataract surgery.
SymptomsAstigmatism makes it difficult to see fine details, either close up or from a distance.
Signs and testsAstigmatism is easily diagnosed by a standard eye exam with refraction test. Special tests are not usually required.
Children or others who cannot respond to a normal refraction test can have their refraction measured by a test that uses reflected light (retinoscopy).
TreatmentMild astigmatism may not need to be corrected.
Glasses or contact lenses will correct astigmatism.
Laser surgery can help change the shape of the cornea surface to correct astigmatism, along with nearsightedness or farsightedness.
Expectations (prognosis)The right glasses or contact lenses, or laser vision correction can usually correct vision to normal.
ComplicationsUncorrected astigmatism in only one eye may cause amblyopia.
Calling your health care providerCall for an appointment with your health care provider or ophthalmologist if vision problems worsen, or do not improve with glasses or contact lenses.
ReferencesOlitsky SE, Hug D, Smith LP. Abnormalities of refraction and accommodation. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 619.
White PF, Scott CA. Contact lenses. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2008:chap 2.9.
Kramarevsky N, Hardten DR. Excimer laser photorefractive keratectomy. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2008:chap 3.4.
Reviewed ByReview Date: 07/28/2010
Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; and Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
Astigmatism is a medical condition. One in a million patients have it.
the defective curvature on the cornea or lens is called Astigmatism
Eye Doctors
the corner of the eye
Having astigmatism does not directly cause your eyes to shake back and forth. Eye shaking, or nystagmus, is typically caused by other underlying issues such as neurological conditions, inner ear problems, or medications. Astigmatism is a refractive error that affects how light enters the eye, leading to blurry vision, but it does not cause eye shaking.
No. Anisocoria is a difference in pupil size and has nothing to do with astigmatism, which is a variation of the cornea or lens of the eye.
Astigmatism old ages
No, a scratch typically will not cause astigmatism to worsen. Astigmatism is usually caused by imperfections in the curvature of the eye's cornea or lens, and it is not typically affected by external factors like scratches. If you have concerns about changes in your astigmatism, it's best to consult with an eye care professional for an evaluation.
The eye. Astigmatism is when the cornea (the clear dome that covers the pupil) or the lens of your eye is not its usual perfectly round shape. Instead it's an oval shape, a bit like a rugby ball.
Astigmatism can cause blurry or distorted vision, eye strain, headaches, and difficulty seeing in low-light conditions. It occurs when the cornea or lens of the eye is irregularly shaped, leading to difficulty focusing light onto the retina. Regular eye exams can help diagnose and correct astigmatism with glasses, contacts, or refractive surgery.
No, you can only be either short or long sighted. An astigmatism means you need a cylinder in your glasses to see properly. You can be either far sighted or near sighted and also have an astigmatism.
No, not really. Astigmatism simply means your eye is shaped more like a football than a baseball, and can be corrected with glasses. Eye pressure is the inflation pressure of the eyeball, like measuring the pressure of your tires. The eye pressure may be slighty off if measured on a patient VERY high astigmatism, but only by about one point, which is basically not significant. We usually don't pay attention to the astigmatism when measuring eye pressure.