Astigmatism | Overview
What is astigmatism?
Astigmatism is a common condition that causes blurry vision. Typically, the cornea, the clear outer layer of the eye, is dome-shaped, like the top of a basketball. But with astigmatism, the cornea is shaped more like a football. This changes the way light enters the eye and makes objects both near and far appear blurry. A child can have astigmatism in one or both eyes.
Astigmatism is common in infants and often clears up on its own by the time a child is one year old. Children with myopia (nearsightedness) or hyperopia (farsightedness) are more likely to have astigmatism. Astigmatism affects Hispanic children at higher rates than other children.
Astigmatism is a refractive error. Nearsightedness (myopia) and farsightedness (hyperopia) are also refractive errors.
- Hyperopia is a condition in which an image of a distant object becomes focused behind the retina, making objects up close appear out of focus.
- Myopia is a condition in which, opposite of hyperopia, an image of a distant object becomes focused in front of the retina, making distant objects appear out of focus.
Up to 28 percent of children have at least one of these common vision problems, which tend to run in families.
Children with undiagnosed astigmatism may struggle in school, which teachers or parents could wrongly interpret as a sign of a learning disability. It is important for all children to have regular eye exams, starting when they are infants and throughout their school years. Prescription eyeglasses can correct a child’s vision.
What are the symptoms of astigmatism?
If a child has astigmatism, objects close to them and far away may appear blurry or distorted.
Other symptoms include:
What causes astigmatism?
Astigmatism is caused by an abnormal curvature of the cornea that changes the way light enters the eye and travels to the retina. The retina is a light-sensitive area at the back of the eye that converts light into signals for the brain. In a healthy eye, light reaches the retina as a single focal point . With astigmatism, the retina receives light in multiple focal points, causing objects up close and at a distance to appear blurry.
Researchers do not know why some children have astigmatism. The condition tends to run in families and children with myopia or hyperopia are at higher risk of astigmatism. Smoking during pregnancy may increase the chance that a child will have astigmatism.
How we care for astigmatism
The Department of Ophthalmology at Boston Children's Hospital offers the latest and best in diagnostics and care for children with vision problems, no matter how simple or complex. Children and families come from around the world to our Eye Center for the most advanced vision testing, diagnostics and treatment available for of all types of visual impairments.
Astigmatism | Diagnosis & Treatment
How is astigmatism diagnosed?
Starting at about six months, children should have regular eye exams to catch conditions like astigmatism, myopia and hyperopia. An eye doctor (ophthalmologist) will examine the child’s eyes and measure the shape of the corneas. When the child is old enough, the eye doctor will test their ability to focus on objects up close, middle distance and far away.
How is astigmatism treated?
Most mild cases of astigmatism can be corrected with prescription eyeglasses or contact lenses. In children with astigmatism, eyeglasses tend to work better than contact lenses.
In some cases, the child’s eye doctor may suggest a procedure called corneal cross linking to prevent the condition from progressing further. This procedure increases the rigidity of the cornea so that it does not become more misshapen over time.