Strabismus and Amblyopia

What is 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 can 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.

What are the complications of strabismus?

  • amblyopia 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 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.

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, schedule an appointment for an eye exam with an ophthalmologist:

  • during the first three months of life, the eyes are wandering outward all the time or the eyes are crossed inward
  • after 3 months of age, one or both of eyes is wandering out or crossing in
  • tilting of the head in order to effectively line up the eyes to use them together or squinting one eye, especially in bright sunlight, to block out a double image resulting from the misaligned eyes pointing in different directions
  • red eye reflection in one eye
  • when a sibling has strabismus

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:

  • Duane syndrome
  • Moebius syndrome
  • thyroid eye disease
  • nerve damage
  • cerebral injuries
  • fracture of the orbital wall

Risk factors for strabismus may 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

How we care for strabismus

The Pediatric Strabismus Service at Boston Children's Hospital 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 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.