Lazy Eye (amblyopia)
Lazy eye (amblyopia) is a reduction in visual acuity that results from abnormal visual development during infancy and early childhood. Lazy eye usually affects just one eye, but it may affect both eyes. With lazy eye, there is no apparent damage or abnormality to the eye. Lazy eye is the leading cause of decreased vision among children. Left untreated, the loss of vision may range from mild to severe.
Lazy eye develops when nerve pathways between the brain and the eye aren't properly stimulated. This can lead to a condition in which the brain favors one eye, usually due to poor vision in the other eye. The weaker eye tends to wander. Eventually, the brain may ignore the signals received from the weaker — or lazy — eye.
Conservative treatments such as corrective eye wear or eye patches can often correct lazy eye. Sometimes, lazy eye requires surgical treatment.
Signs and symptoms of lazy eye include:
An eye that wanders inward or outward
Eyes that may not appear to work together
Poor depth perception
Although lazy eye usually affects just one eye, it's possible for both eyes to be affected.
Anything that blurs a child's vision or causes the eyes to cross or turn out may cause lazy eye. Some of the more common causes include:
Strabismus. The most common cause of lazy eye is strabismus — an imbalance in the muscles responsible for positioning of the eyes. This imbalance can cause the eyes to cross in or turn out. The muscle imbalance prevents the eyes from tracking in a coordinated way with each other.
Anatomic or structural abnormality of the eye. Sometimes lazy eye is the result of an abnormality, such as an abnormal central retina or a cloudy area in the lens of the eye (cataract). In other cases, an abnormal eye shape or a size difference between the eyes contributes to lazy eye.
Tumor. Occasionally, a wandering eye is the first sign of an eye tumor.
Lazy eye tends to run in families. Lazy eye may be more likely among children who were born prematurely or those who have developmental delays as they get older.
Left untreated, lazy eye can cause permanent vision loss. In fact, lazy eye is the most common cause of single-eye vision impairment in young and middle-aged adults, according to the National Eye Institute.
Vision checks are often a routine part of well-child checkups — especially if there's a family history of crossed eyes, childhood cataracts or other eye conditions. For all children, a complete eye exam is usually recommended between ages 3 and 5. If you notice your child's eye wandering at any time beyond the first few weeks of life, it's important to have a medical evaluation first to check for other causes of your diseases.