What are the other Names for this Condition? (Also known as/Synonyms)

• Crossed Eye
• Squint
• Wandering Eye

What is Strabismus? (Definition/Background Information)

• Strabismus, also known as Squint or Crossed Eye, is an eye condition in which both eyes cannot simultaneously focus on the same place. The eyes do not align or work together correctly in this visual condition. One eye may turn in, out, up, or down, while the other eye focuses on a particular object
• A majority of the cases are observed in infants and young children. Strabismus can be constant or intermittent and may affect one or both eyes. The risk factors include a family history of Strabismus, certain medical conditions (such as cerebral palsy), premature birth, and refractive errors
• The exact cause of Strabismus can vary. It may result from problems with the eye muscles, nerve pathways, or the control center in the brain that manages eye movements. The condition may develop later in life, too
• Misalignment of the eyes can result in poor depth perception, double vision, and the development of amblyopia (a neurological condition causing partial or complete loss of vision in one eye). Strabismus is primarily observed in individuals with severe hyperopia (farsightedness) or poor eye muscle control
• Strabismus diagnosis involves a comprehensive eye examination, including visual acuity tests, eye alignment assessment, and eye movement evaluation. The treatment options include corrective lenses, eye patches, vision therapy, and, in some cases, surgery to correct the alignment of the eyes
• The prognosis for Strabismus varies based on its underlying cause, severity, and how promptly it is addressed. Early detection and treatment can help prevent complications and promote normal vision development. Regular eye check-ups in childhood are essential

Who gets Strabismus? (Age and Sex Distribution)

• Strabismus is a widespread condition. It is reported in nearly 4-5% of the general population
• Most cases of Strabismus are diagnosed in infants and young children under the age of 3 years. Occasionally, older children and adults may also develop this condition
• Males and females are affected in equal numbers
• The condition is seen globally in individuals of all races and ethnicity 

What are the Risk Factors for Strabismus? (Predisposing Factors)

Some of the risk factors for Strabismus include:

• Family history of Strabismus
• Preterm birth or low weight at birth
• Significant farsightedness that was left uncorrected for a long time
• Incorrect prescription to correct refractive errors
• Head injury
• Down syndrome
• Cerebral palsy or brain stroke
• Brain tumors
• Amblyopia
• Retinopathy of prematurity (ROP)
• Cataract
• Corneal scar

It is important to note that having a risk factor does not mean one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Strabismus? (Etiology)

The misalignment of eyes in Strabismus may take place due to:

• Issues with eye muscle control; poor eye coordination
• Damage in the area of the brain responsible for eye movement
• Damage to the nerves that convey information from the brain to the eye muscles

Strabismus may be classified based on how the eye turns (inward, outward, upward, or downward), the frequency of occurrence of the condition, and the eye involved (left or right or both eyes alternating). The common types include accommodative esotropia (most common pediatric Strabismus) and intermittent exotropia.

Other Strabismus types include:

• Alternating Strabismus
• Congenital Esotropia
• Constant Strabismus
• Esotropia
• Exotropia
• Infantile Esotropia

What are the Signs and Symptoms of Strabismus?

The signs and symptoms depend on the type and severity of Strabismus. The common signs and symptoms include:

• Crossed eyes - the eyes appear misaligned and move in different directions
• Moving the head to look at objects
• Headaches due to eye strain
• Poor depth perception
• Double vision
• Frequent blinking under bright light
• Squinting or closing one eye in bright sunlight
• Lack of binocular vision
• Fatigue
• A single eye or both eyes may be involved/affected

Associated signs and symptoms of the underlying condition/disorder, if any are present, may also be observed.

How is Strabismus Diagnosed?

A diagnosis of Strabismus may involve the following tests and exams:

• Physical examination and medical history evaluation
• Assessment of signs and symptoms
• General eye exam: A simple eye exam may be sufficient to recognize the condition. However, more extensive studies and tests may be undertaken to understand the extent of Strabismus
• Visual acuity test using a unique and standardized test chart (Snellen chart)
• Refraction studies using various instruments
• Retinal birefringence scanning (RBS)
• Alignment and focusing testing
• Fundoscopic (ophthalmoscopic) examination by an eye specialist who examines the back part of the eye (or the fundus)
• Slit-lamp examination
• Imaging studies, including CT and MRI scans of the head and neck region, if necessary

Tests and exams to determine an underlying cause, if present, may be necessary.

Many other clinical conditions may cause vision loss in children. Your optometrist or pediatric ophthalmologist may perform additional tests to rule out other conditions.

What are the possible Complications of Strabismus?

Strabismus may impact vision development, especially in children. The complications of untreated Strabismus may include:

• Vision problems causing an inability to read, drive, play sports, or perform simple tasks
• Development of amblyopia (lazy eye), where the brain favors one eye over the misaligned one, potentially leading to permanent vision impairment
• Reduced employment opportunities
• Impaired social life due to embarrassment, poor eye contact, and a feeling of awkwardness
• Low self-esteem and negative self-image
• Decreased quality of life

Complications arising from the underlying/associated condition, if any, may be noted.

How is Strabismus Treated?

Strabismus may be treated successfully with early intervention and adequate therapy. The treatment depends on the type and severity of Strabismus and may include:

• Prescription eyeglasses or contact lenses (usually the first line of treatment)
• Temporary eye patches, especially for young children
• Use of prism lenses (therapeutic lenses)
• Vision therapy - it is a form of training to help the eye muscles and brain work together
• Eye surgery to correct Strabismus; in some cases, more than one surgery may be needed to rectify the condition
• Botulinum toxin therapy for individuals older than 12 years

The treatment measures include treating the symptoms and managing the underlying condition/disorder.

How can Strabismus be Prevented?

Currently, there are no known prevention methods for Strabismus. Early recognition and treatment are important to prevent symptoms from getting worse.

• It is vital to screen children for eye health very early (before age six months) and regularly (at least once between ages 3 and 5 years)
• Periodic eye examinations for older children and adults, especially if there is a high risk for the development of the condition
• Individuals with hyperopia (farsightedness) are mainly required to have regular eye testing and adjust their eyeglasses accordingly
• Undertaking early and adequate treatment of any health issues, such as Down syndrome or cerebral palsy, is important

What is the Prognosis of Strabismus? (Outcomes/Resolutions)

• Young children who are diagnosed early and receive proper treatment for Strabismus usually recover completely and have a good prognosis
• However, if diagnosis and treatment are delayed, the vision may be irreversibly affected

With appropriate intervention, many individuals with strabismus can achieve improved eye alignment and functional vision. However, treatment success may depend on individual factors and the specific characteristics of the condition.

Additional and Relevant Useful Information for Strabismus:

The following DoveMed website link is a helpful resource for additional information:

https://www.dovemed.com/diseases-conditions/amblyopia