Strabismus is a visual disorder in which the eyes are misaligned and point in different directions. It is a common condition among children that affects about 4% of all children in the United States. It can also occur later in life. When the eyes are misaligned, typically one eye fixates on an object while the other eye turns in (esotropia), out (exotropia), up (hypertropia), or down (hypotropia). When this occurs, two different images are sent to the brain, confusing it, and further resulting in the brain rejecting the image from the weaker eye. Therefore, abnormal eye alignment blocks normal vision development in children, inhibiting their ability to perform in school and necessary day-to-day activities.

Strabismus Child Patient


Experts don’t completely understand the cause of this condition, 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 it, including thyroid eye disease, nerve damage, and brain injuries. Risk factors include family history of strabismus, prematurity or low birth weight, retinopathy of prematurity, as well as conditions that affect vision, such as cataracts, severe ptosis and corneal scars.


Strabismus cannot be prevented. However, early diagnosis and proper treatment is essential to preventing vision loss resulting from amblyopia, also called “lazy eye”, and other complications stemming from strabismus. Children should be monitored closely during infancy and the preschool years to detect potential eye problems, especially if there is family history with strabismus. Regular screening for young children includes testing for strabismus using light reflex for infants and cover testing for preschool-aged children.


Treatment can preserve vision, straighten the eyes, and restore binocular (two-eyed) vision.

After a complete eye examination, an ophthalmologist can recommend appropriate treatment. In some cases, eyeglasses are prescribed. Other treatments may involve surgery to correct the unbalanced eye muscles or to remove a cataract. Covering or patching the strong eye is often necessary.

Beyond vision impairment, this condition has lifetime consequences. Many individuals become societal outcasts and have difficulty getting married or finding a job. So even when vision may not be improved, surgery can improve an individual’s chance at a normal life.

SEE International & Strabismus Around the World

Ophthalmologists are rare in the developing world, and many countries are in desperate need of trained eye surgeons.
SEE is working diligently to reduce the number affected by this condition around the world by:

  • Performing corrective surgeries
  • Connecting patients with local doctors
  • Teaching appropriate surgical techniques.
  • Training local eye care personnel in ophthalmology in rural and urban areas.
  • Strengthening local health care infrastructure

More Resources


  • SEE volunteers, Dr. Jesus Fuentes Mujica, ophthalmic technician Luis Velasco and Dr. Maxwell Cheng cared for hundreds of Peruvians, providing free eye exams and sight-restoring surgeries. Dr. Mujica is a Peruvian ophthalmologist who goes on close to 20 medical missions in his own country each year. Seeing how worn his one set of surgical instruments were from many years of use, Dr. Cheng generously gave him his own instrument set so that Dr. Mujica could continue his work to help the needy in the rural areas of Peru.

    March 27


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