KidsMD Health Topics

Strabismus and Amblyopia

  • Overview

    Here are some of the basics about strabismus:

    • Strabismus is one of the most common eye conditions in children, affecting between 2 and 4 percent of the population.
    • Strabismus occurs when the eyes are not aligned properly. One or both of your child’s eyes may turn inward (esotropia), outward (exotropia), upward (hypertropia) or downward (hypotropia).
    • Your child can be born with strabismus or it be acquired later in life. Strabismus can also develop as the result of an accident or other health problem. 
    • In some children, strabismus is intermittent, while in others it is always present.
    • Early diagnosis is essential in preventing vision loss that occurs as a result of amblyopia, also called “lazy eye". Amblyopia from strabismus occurs when vision does not develop normally during childhood because the eyes are not aligned.
    • Treatment of strabismus may include eyeglasses, patching or eye muscle surgery.

    How Boston Children's approaches strabismus

    The Pediatric and Adult Strabismus Services at Boston Children's offer comprehensive evaluation and correction of strabismus in babies, children and adults of all ages. Our highly experienced pediatric ophthalmologists are known locally and nationally for handling the most difficult cases of strabismus.

    Many children and adults with complex strabismus that involves multiple eye muscles and others who have had failed attempts at correcting strabismus elsewhere are routinely referred to Boston Children's. Here, we use baby- and child-friendly eye exams to detect strabismus and our physicians adopt innovative approaches to straighten your child’s eyes. Adults with strabismus are referred to our pediatric practice because ophthalmologists specially trained in childhood eye conditions have expertise in the delicate eye muscle surgery typically required to straighten the eyes.

    “Aligning the Eyes” webcast

    David Hunter, MD, PhD, ophthalmologist-in-chief, led a panel discussion about Duane syndrome, a congenital form of strabismus in which the eye has a limited range of motion. Boston Children’s is one of the few pediatric institutions that performs a sedated adjustable suture procedure. Learn more about this procedure and the webcast in the newsroom.


    Reviewed by: Carolyn Wu, MD. © Boston Children’s Hospital; 2012.

    Boston Children's Hospital
    Pediatric Strabismus Service
    300 Longwood Ave.
    Boston MA 02115


  • In-Depth


    What causes strabismus?

    Experts don’t completely understand the cause of strabismus, but it results from the failure of the eye muscles to work together.

    Idiopathic (resulting from an unknown cause) strabismus is the most common type. Other conditions can also cause strabismus:

    Risk factors for strabismus include the following:

    • Family history of strabismus
    • Prematurity or low birth weight
    • Retinopathy of prematurity
    • Conditions that affect vision, such as cataracts, severe ptosis and corneal scars
    • Muscular abnormalities
    • Neurological abnormalities
    • Amblyopia (or lazy eye) 

    How common is strabismus?

    As many as 4 percent of children have strabismus.


    What are the symptoms of strabismus?
    Babies and children with strabismus should be checked right away to prevent amblyopia, which results in loss of vision and depth perception due to the misaligned eye. Amblyopia can occur even if the eye is only slightly misaligned, because a developing child's brain will stop communicating with that eye, shutting it off. This is why amblyopia is sometimes referred to as "lazy eye". 

    Unfortunately, it isn't always easy for parents to tell if a child's eyes are misaligned, particularly in those children with a mild case of strabismus. If your child is showing any of the following signs and symptoms of strabismus, you should call today and schedule an appointment for an eye exam with one of our pediatric ophthalmologists.

    • Strabismus in newborns. Many parents are told that a baby’s eyes may not be completely aligned in the first three months of life. It is not unusual for a baby's eyes to occasionally wander outward, but if this happens all the time or if the eyes cross inward, especially constantly, your baby should have an eye exam.
    • Strabismus after 3 months of age. If you notice one or both of your baby's eyes wandering out or crossing in after 3 months of age, your baby should have an eye exam.
    • Head tilting or squinting. Children with strabismus may tilt their head in order to effectively line up the eyes to use them together or they may squint one eye, especially in bright sunlight, to block out a double image resulting from the misaligned eyes pointing in different directions. Children who show these signs should have an eye exam.
    • Red eye reflection in one eye. An annoyance in family pictures, the "red eye" reflection can sometimes provide valuable information about vision. If "red eye" is showing in only one eye rather than both eyes, it may be a tip-off that your child is having a vision problem and should have an eye exam.
    • When a sibling has strabismus. If a brother or sister has been diagnosed with strabismus, it is a good idea to have your baby or child examined, even if there are no obvious signs of the problem.


    What are the complications of strabismus?

    • Amblyopia (lazy eye) occurs in up to one-half of younger children.
    • Diplopia (double vision) can occur in acquired strabismus in older children and adults.
    • Problems in socializing or working resulting from the appearance and function of the eyes

    What is the long-term outlook for my child?

    It depends upon the underlying cause of your child’s strabismus, but what is true in all cases is that the sooner the condition is diagnosed, the more effective the treatment will be.

  • Tests

    How is strabismus diagnosed?

    Strabismus is diagnosed during an eye examination. Evaluation of the eyes and vision should be performed in the pediatrician's office at every well-child visit. But if your child is having symptoms of strabismus or other eye disorders at any age, a complete eye examination by an ophthalmologist should be performed.

    Screening procedures

    There are a variety of tests that can help detect strabismus and associated amblyopia. Light reflex testing evaluates the alignment of the eyes by having your child look directly at a point of light. Another test uses prisms to analyze whether your child’s eyes are properly aligned. If your child is not yet able to talk, vision can be assessed by evaluating your child’s ability to fixate on a moving object or your child’s response when one of the eyes is covered. If your child is older, a standard eye chart with either letters or pictures will be used to test vision.

    Your child’s doctor will also ask you about your family history and how and when your child’s strabismus appeared. To provide the most effective care, it is important to determine whether your child was born with strabismus or acquired it as the result of another health problem.

    After we complete all necessary tests, our experts meet to review and discuss what they learned about your child's condition. Then we will meet with you and your family to discuss the results and outline the best treatment options for your child.

    Did you know?

    The American Academy of Pediatrics and American Academy of Ophthalmology recommend that a child's doctor perform a vision screening at every well-child visit.

  • The doctors and care team at Boston Children's Hospital specialize in family-centered care, which means that from your first visit, you'll work with a team of professionals who are committed to supporting all of your family's needs and that you'll be an essential part of your child's care team.

    When should my child be treated?

    If strabismus is treated early, your child will have a better chance to use his or her eyes together to develop binocular vision and depth perception. It's also important to treat strabismus soon after diagnosis to avoid the onset of amblyopia, which can result in permanent vision loss. 

    How does Boston Children's treat strabismus?

    Each year, our pediatric ophthalmologists see numerous children with strabismus. We recognize that every child's condition is different with its own unique challenges — and as a result, strategies to correct one case may be different than the approach in another case.

    Mild strabismus

    • Glasses: Your child's eye doctor may prescribe glassesto correct the alignment problem.
    • Patching: Sometimes your doctor may recommend placing a patch over the normally functioning eye for a number of hours every day. "Patching" can help remind the brain that it needs to pay attention to both eyes, which sometimes can improve the alignment.

    Severe strabismus

    • Eye muscle surgeryis typically needed to straighten the eyes and prevent vision loss when other interventions don't work. 
    • The surgery involves detaching the muscle or muscles that is causing misalignment and reattaching it or them to a new spot.

    What makes Boston Children's different?

    If you come to Boston Children's, you have access to pediatric ophthalmologists who routinely treat difficult cases. Our eye doctors are actively involved in research that is shaping the way strabismus is detected and treated around the country and the world.

    Some of our more innovative approaches for strabismus include:

    Botox injections

    Very few places in the New England region and in the country offer Botox (Botulinum Toxin A) injections as an option for treatment in children with strabismus. At Boston Children's, eye doctors can occasionally use Botox instead of eye muscle surgery to correct strabismus.

    Sometimes, this method proves effective in children for whom surgery has not corrected the misalignment. For adults and older children, this treatment can be given in the office. For young children, the procedure is performed in the operating room with a brief anesthesia but without need for incisional muscle surgery. Curious about Botox injections? Here's what you need to know.

    Adjustable sutures in eye muscle surgery

    Adjustable sutures allow our ophthalmologists to readjust the position of your child's eye in the recovery room to avoid the need to schedule additional surgery. It may be hard to believe that a child would sit still for the adjustment of adjustable sutures, but our surgical and anesthesia teams perform these adjustments routinely and know how to help a child stay calm and cooperative throughout the process.

    If a child is too young or too fearful to cooperate for adjustment, the procedure can be completed with a brief secondary anesthetic in the recovery room without needing to return for surgery. Want to read more about eye muscle surgery at Boston Children's? Here's what to expect.

    Coping and support

    There are many resources available for your family.

    Boston Children's resources for families:

    Patient to patient: Are you interested in talking with someone else whose child has been treated for strabismus or amblyopia? We can put you in touch with other families who have been through similar experiences and can share their stories.

    On our For Patients and Families site, you can read all you need to know about:

  • Your Story

    Strabismus and amblyopia

    Steven: A new look on life

    Steven McCarthy never imagined he would someday drive without prism glasses, participate in sports or be able to sit through a movie or play without developing headaches. Read Steven’s story.

    Strabismus and amblyopia

    Janice: Starting again;

    Janice Pauk thought that she was having an anxiety attack when she was driving and began to see red flashes before her. All of a sudden, she couldn't tell how far she was from the car in front of her. Read Janice's story.

    Strabismus and amblyopia

    Janet: Discovering a cure exists

    For nearly two years after taking a terrible fall that left her with strabismus (misaligned eyes), Janet Gurski, 72, searched for treatment that would restore her depth perception and alleviate the double vision that became unbearable. Yet, she was repeatedly told that there was no cure and that she would have to live with it. Read Janet's story.

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