Is Strabismus Genetic? Understanding Causes, Risks, and Inheritance

Explore the genetic and environmental factors that contribute to strabismus, its inheritance patterns, and how risks can be managed.

By Medha deb

Created on Sep 25, 2025

Explore the genetic and environmental factors that contribute to strabismus, its inheritance patterns, and how risks can be managed.

Is Strabismus Genetic?

Strabismus, commonly known as eye misalignment, is a condition where one or both eyes do not align properly. It frequently appears in childhood but can develop at any age. One important question is whether strabismus is inherited, and what other factors may contribute to its development. This article examines the latest research on the genetic and environmental causes of strabismus, the patterns of inheritance, associated risks, and prevention.

What Is Strabismus?

Strabismus is the term for a condition in which the eyes do not line up with each other. One eye may turn inward (esotropia), outward (exotropia), upward (hypertropia), or downward (hypotropia). It often results in double vision and can impair depth perception, especially when it develops in childhood. In severe cases, strabismus can cause amblyopia (“lazy eye”) and social or psychological challenges.

Prevalence: Affects about 2–4% of children worldwide.
Can occur at any age, but commonly detected in early childhood.
May affect one or both eyes intermittently or constantly.

Signs and Symptoms of Strabismus

People with strabismus may notice one or more of the following:

Eyes that appear to point in different directions
Frequent squinting or closing one eye, especially in bright light
Tilted or turned head to maintain single vision
Double vision (diplopia) or blurred vision
Difficulties with depth perception

Is Strabismus Genetic?

Many cases of strabismus show a genetic link. Family history is a significant factor, indicating that genes play a role in the condition’s development. However, genetics alone does not entirely account for strabismus, as some individuals develop it without any known family history, suggesting involvement of multiple factors.

Higher risk in children: Children with a parent or sibling affected by strabismus are at increased risk of developing the condition themselves.
Associated genetic conditions: Strabismus may accompany genetic or developmental disorders such as Down syndrome and cerebral palsy.
Family patterns: Several studies show variations in inheritance patterns, with dominant, recessive, and sex-linked mechanisms proposed.

The Genetic Connection

Genetic predisposition is frequently identified in cases of strabismus:

Monozygotic (identical) twins have higher concordance rates for strabismus compared to dizygotic twins, supporting strong genetic influence.
Family clustering is common: up to 65% familial incidence has been reported in some studies, particularly with esotropia.
Genetic risk is higher than the general population but environmental factors still play an important role.

However, the genetic pathways are complex and heterogeneous. No single gene or mutation is responsible for all forms of strabismus, and multiple genetic mechanisms may contribute to the condition’s expression within the same family.

How Is Strabismus Inherited?

Research indicates that strabismus often runs in families, but the exact patterns of inheritance vary:

Dominant inheritance: In some families, one copy of a mutated gene may be enough to cause strabismus.
Recessive inheritance: Other cases require mutations from both parents.
Sex-linked inheritance: Strabismus may rarely follow patterns linked to sex chromosomes, but most studies find no significant difference in prevalence between males and females.

Studies utilizing genome-wide association have identified two genetic risk loci in white populations and three rare copy number variants (CNVs) that increase strabismus risk. These genetic findings carry small effect sizes, meaning that they increase risk but are not solely responsible for the condition.

Family Studies and Twin Studies

Type of Study	Key Findings
Family Studies	18–65% familial incidence; hereditary factors significant, but environmental influence remains
Twin Studies	Higher rates in identical twins than non-identical, supporting strong genetic contribution
Mendelian Inheritance Theories	Simple Mendelian (single gene) models do not fully explain strabismus inheritance

Environmental and Other Risk Factors for Strabismus

Genetics is only part of the story. Several environmental factors and acquired conditions can increase a child’s risk of developing strabismus:

Low birth weight and prematurity
Maternal smoking during pregnancy
Intrauterine drug exposure
Advanced maternal age
Neurologic diseases or anomalies
Brain injuries or infections during infancy
High uncorrected farsightedness (hyperopia) or astigmatism
Significant eye or head trauma

Some of these environmental factors are linked to epigenetic changes—chemical modifications that affect how genes are expressed, rather than the genes themselves. For example, methylation changes in infants associated with maternal smoking, birthweight, prematurity, and advanced maternal age may influence strabismus risk by altering gene function.

Types of Strabismus and Genetic Associations

Esotropia: Eye turns inward; more commonly familial
Exotropia: Eye turns outward; familial clustering sometimes observed
Hypertropia/Hypotropia: Eye turns upward/downward; less common, genetic links under investigation
Congenital cranial dysinnervation disorders: Genetic causes disrupt development or guidance of motor neurons controlling eye movement
Comitant strabismus: Most common form, genetic and environmental mechanisms examined in recent studies

How Do Genetics and Environment Interact?

Recent research proposes a mechanistic link between genetic predisposition and environmental influences:

Genetic mutations and CNVs may alter how genes regulate eye development and muscle coordination
Environmental exposures influence methylation and epigenetic regulation, affecting gene expression
Neurological and developmental factors may mediate or exacerbate underlying genetic tendencies

This interplay suggests that strabismus often results from a combination of subtle genetic risks and outside factors, rather than a single causal event.

Diagnosing Genetic Strabismus

A comprehensive approach is necessary for diagnosing genetically-linked strabismus:

Detailed family and medical history
Ophthalmological assessment, including alignment and vision tests
Genetic counseling when multiple family members are affected, or syndromic features are present
Referral for neurological evaluation if other developmental disorders present

Genetic Testing

While genetic testing for strabismus is not routine, it may be recommended if the condition appears with other syndromic signs or known congenital disorders.

Can Strabismus Be Prevented?

Preventing strabismus is challenging because genetic risk cannot be changed. However, early detection and management of contributing factors may reduce severity or impact:

Monitor children with a family history of strabismus for signs of eye misalignment
Treat farsightedness and astigmatism early to avoid eye strain complications
Avoid environmental risk factors like maternal smoking and manage prenatal health
Promptly address neurological, developmental, and trauma-related conditions

Routine vision screening and pediatric examinations are pivotal for early diagnosis and treatment.

Treatment Options for Strabismus

Treatment depends on severity, age of onset, and underlying cause. Options include:

Corrective eyeglasses or contact lenses (especially for refractive errors)
Vision therapy (exercises to strengthen eye coordination)
Prism lenses to adjust alignment
Surgical intervention on eye muscles when conservative measures fail
Treatment for amblyopia (patching, drops, or vision exercises)

Frequently Asked Questions (FAQs)

Q: If I have strabismus, will my child also have it?

A: Having strabismus raises your child’s risk compared to the general population but does not guarantee they will develop it. Family history is a notable risk factor, but environmental and developmental factors are also important.

Q: Is strabismus always genetic?

A: Not all cases are genetic. Many occur without any family history, caused by factors such as premature birth, neurological disorders, or injury.

Q: Can strabismus skip generations?

A: Yes, because its genetic inheritance is complex and may involve multiple genes and environmental triggers, strabismus can skip generations or affect some family members but not others.

Q: What increases a child’s risk besides genetics?

A: Prematurity, low birth weight, advanced maternal age, uncorrected vision problems, brain injuries, and certain prenatal exposures (like smoking) all increase risk.

Q: Can early treatment make a difference?

A: Yes. Early diagnosis and intervention help prevent complications like vision loss and support better outcomes, especially in children.

Takeaways

Strabismus is a condition with both genetic and environmental causes.
Family history increases risk, but not all cases are inherited.
Early screening and proper management are crucial for best outcomes.
Ongoing research into genetic mechanisms may offer new insights for prevention and treatment.

References

Frontiers in Ophthalmology: Genetics of Strabismus research
Visionary Eye Care: Is Strabismus Genetic?
Journal articles on Strabismus Genetics and Twin Studies
Healthline: Crossed Eyes (Strabismus) Symptoms and Causes

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

Read full bio of medha deb