What Is Astigmatism?
Astigmatism is a type of refractive error. It can be seen with other refractive errors like myopia (nearsighted), hyperopia (farsighted), or presbyopia (decrease in the lens ability to focus on near with age). A refractive error means that the shape of the eye does not allow light to bend properly. Light has to be bent by the lens or cornea correctly before it reaches the retina. If this light is not bent or refracted correctly the image will not focus exactly on the retina and cause a blur. A nearsighted eye focuses the light rays in front of the retina. A farsighted eye focuses light rays behind the eye. A presbyopic eye has a lens which does not bend with near work. Astigmatism is when there is a curve in the eye which distorts the light rays before it reaches the retina. All refractive errors can cause symptoms of blurry vision.
Astigmatism can be caused by either the clear cornea in front of the eye or from the lens behind the iris. If either have an irregular shape, the light rays will not be refracted as they should. People without astigmatism have a round, spherical cornea. People with astigmatism usually have an oval shaped cornea similar to a football. Astigmatism can develop from the lens within the eye and is often seen when people get older and develop cataracts.
Symptoms of Astigmatism
There are many symptoms of astigmatism. Blurred vision, squinting, light sensitivity, headaches, eyestrain, halos, and difficulty focusing or concentrating for long periods can all be related to astigmatism.
Astigmatism can be diagnosed by an ophthalmologist during a routine eye exam. First, a careful history can often help make the diagnosis. Next, testing a patient’s visual acuity and a careful refraction can pick up astigmatism. Astigmatism can develop in children or adults.
Contact Lens for Astigmatism
Astigmatism is very common. Many of us have some degree of astigmatism. Some people are more symptomatic from their astigmatism. Astigmatism can be corrected with glasses, contact lenses, refractive surgery and now with cataract surgery. There are many new soft, toric contact lenses on the market that can address the symptoms of astigmatism. Daily, toric soft contact lenses are a great option for patients with dry eyes and contact lens intolerance. Toric intraocular lens implants have greatly improved the success and vision of patients undergoing cataract surgery.
All of the ophthalmologists at Eye Associates of Washington, DC are trained and highly skilled in diagnosing and treating astigmatism to help patients achieve their best visual potential.
Melanie Buttross, MD
Board Certified Ophthalmologist
Washington DC, Tyson’s Corner
