Strabismus | Symptoms and Causes

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, 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:

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 (or lazy eye)