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Strabismus

Disease Details

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Description: Strabismus is a condition where the eyes do not properly align with each other when looking at an object.
Type: Strabismus can be classified into several types based on the direction of eye misalignment: esotropia (inward turning), exotropia (outward turning), hypertropia (upward turning), and hypotropia (downward turning).

The genetic transmission of strabismus is often considered multifactorial, meaning it can result from a combination of genetic and environmental factors. In some cases, it can follow an autosomal dominant pattern, where inheriting one copy of the mutated gene from an affected parent can lead to the condition. However, the exact genetic mechanisms can vary widely and are not fully understood.
Signs And Symptoms: When observing a person with strabismus, the misalignment of the eyes may be quite apparent. A person with a constant eye turn of significant magnitude is very easy to notice. However, a small magnitude or intermittent strabismus can easily be missed upon casual observation. In any case, an eye care professional can conduct various tests, such as cover testing, to determine the full extent of the strabismus.Symptoms of strabismus include double vision and eye strain. To avoid double vision, the brain may adapt by ignoring one eye. In this case, often no noticeable symptoms are seen other than a minor loss of depth perception. This deficit may not be noticeable in someone who has had strabismus since birth or early childhood, as they have likely learned to judge depth and distances using monocular cues. However, a constant unilateral strabismus causing constant suppression is a risk for amblyopia in children. Small-angle and intermittent strabismus are more likely to cause disruptive visual symptoms. In addition to headaches and eye strain, symptoms may include an inability to read comfortably, fatigue when reading, and unstable or "jittery" vision.
Prognosis: When strabismus is congenital or develops in infancy, it can cause amblyopia, in which the brain ignores input from the deviated eye. Even with therapy for amblyopia, stereoblindness may occur. The appearance of strabismus may also be a cosmetic problem. One study reported 85% of adult with strabismus "reported that they had problems with work, school, and sports because of their strabismus." The same study also reported 70% said strabismus "had a negative effect on their self-image." A second operation is sometimes required to straighten the eyes.
Onset: Strabismus, commonly known as crossed eyes, can have varying onset times. It can be present at birth (congenital strabismus) or develop later in childhood or adulthood (acquired strabismus). The exact timing and cause may vary, and early detection and treatment are crucial for better outcomes.
Prevalence: The prevalence of strabismus in the general population is estimated to be about 2-4%. This condition, which involves the misalignment of the eyes, can affect individuals of any age but is commonly diagnosed in childhood.
Epidemiology: Strabismus, commonly known as "crossed eyes," affects approximately 2-4% of the general population. It is a condition characterized by the misalignment of the eyes, where one eye may turn in, out, up, or down relative to the other eye. The prevalence can vary based on age and underlying health conditions, and it is often diagnosed in children, though it can also occur in adults.
Intractability: Strabismus itself is not necessarily intractable. It can often be managed or corrected through various treatments such as glasses, eye exercises, prisms, or surgery, depending on the underlying cause and severity. However, some cases may be more challenging to treat, requiring ongoing management.
Disease Severity: Strabismus severity can vary widely. It may be classified based on factors like the angle of misalignment, the frequency of the misalignment (constant or intermittent), and the involvement of one or both eyes. The misalignment can range from mild to severe, potentially leading to symptoms like double vision, headaches, or eye strain, and, if untreated in children, can cause amblyopia (lazy eye).
Healthcare Professionals: Disease Ontology ID - DOID:540
Pathophysiology: The extraocular muscles control the position of the eyes. Thus, a problem with the muscles or the nerves controlling them can cause paralytic strabismus. The extraocular muscles are controlled by cranial nerves III, IV, and VI. An impairment of cranial nerve III causes the associated eye to deviate down and out and may or may not affect the size of the pupil. Impairment of cranial nerve IV, which can be congenital, causes the associated eye to drift up and perhaps slightly inward. Sixth nerve palsy causes the associated eye to deviate inward and has many causes due to the relatively long path of the nerve. Increased cranial pressure can compress the nerve as it runs between the clivus and brain stem.Evidence indicates a cause for strabismus may lie with the input provided to the visual cortex.Amblyopia may also cause strabismus. If a great difference in clarity occurs between the images from the right and left eyes, input may be insufficient to correctly reposition the eyes. Other causes of a visual difference between right and left eyes, such as asymmetrical cataracts, refractive error, or other eye disease, can also cause or worsen strabismus.
Carrier Status: For strabismus, carrier status is not typically applicable, as it is a condition characterized by misalignment of the eyes rather than a classic hereditary disease with carrier states. Strabismus can have genetic components, but it is often influenced by other factors. It is not considered a single-gene disorder where carrier status (such as in recessive genetic conditions) would be relevant.
Mechanism: Strabismus, commonly referred to as "crossed eyes," is a condition where the eyes do not properly align with each other when looking at an object.

**Mechanism:**
Strabismus occurs due to an imbalance in the muscles that control eye movement. Six muscles control each eye's movement, and these muscles must work together to ensure the eyes align and focus on the same point. When there is a dysfunction in these muscles or their coordination, one eye may turn inwards, outwards, upwards, or downwards while the other eye focuses correctly. This misalignment can disrupt normal binocular vision, leading to issues such as double vision or poor depth perception.

**Molecular Mechanisms:**
The molecular mechanisms underlying strabismus are complex and not fully understood, but several factors are believed to contribute:

1. **Genetic Factors:** Mutations or variations in specific genes associated with muscle development and neural processing might influence the development of strabismus. Gene mutations affecting pathways involved in neurodevelopment and ocular muscle innervation have been implicated.

2. **Neuromuscular Junctions:** Defects in the neuromuscular junction, where nerves communicate with the muscle, can impair muscle function and control. This can result from issues in neurotransmitter release or receptor function which are essential for muscle contraction and movement.

3. **Brain Signaling Pathways:** Disruptions in the neural pathways that coordinate eye movements can lead to strabismus. This includes the brain's inability to properly process visual information or to send appropriate motor signals to the eye muscles.

4. **Extraocular Muscle Tissue:** Changes at the cellular or molecular level in the extraocular muscles themselves can affect their contractility and responsiveness, contributing to misalignment.

Further research is ongoing to better understand the detailed molecular pathways and genetic influences that contribute to the development and progression of strabismus.
Treatment: Treatment for strabismus includes:

1. **Eyeglasses or contact lenses**: Corrects refractive errors that may be contributing to the misalignment.
2. **Prism lenses**: These can be used to reduce the amount of turning the eye must do to see properly.
3. **Vision therapy**: Exercises for the eyes to improve coordination and focusing.
4. **Medications**: Botulinum toxin (Botox) injections can temporarily realign the eyes.
5. **Surgery**: Realigns the eyes by adjusting the muscles around the eyes.

It's important to consult with an ophthalmologist or optometrist to determine the most appropriate treatment plan.
Compassionate Use Treatment: Compassionate use treatment for strabismus, particularly when conventional therapies have failed, could potentially include novel pharmacological agents or surgical techniques currently undergoing clinical trials but not yet approved for general use. Examples might include botulinum toxin injections in specific cases of strabismus that have shown resistance to other treatments. However, compassionate use typically requires a special application process and approval from regulatory authorities.

Off-label or experimental treatments for strabismus may involve the use of drugs such as botulinum toxin A injections, typically used for muscular and neurological conditions, to temporarily paralyze and correct muscle imbalances. Additionally, certain optical or electronic devices designed to improve visual alignment and perception are being researched. These treatments are experimental and should be undertaken with caution and appropriate medical supervision.
Lifestyle Recommendations: Lifestyle recommendations for managing strabismus include:

1. **Regular Eye Exams**: Ensure consistent follow-ups with an ophthalmologist to monitor eye alignment and vision.
2. **Eye Exercises**: Engage in prescribed eye exercises or vision therapy to strengthen eye muscles and improve coordination.
3. **Proper Lighting**: Maintain good lighting while reading or doing close-up work to reduce eye strain.
4. **Healthy Diet**: Consume a balanced diet rich in vitamins and minerals essential for eye health, such as Vitamin A, C, and E.
5. **Protective Eyewear**: Wear appropriate glasses or contact lenses as prescribed to correct vision and alignment issues.
6. **Limit Screen Time**: Reduce prolonged use of digital screens and take frequent breaks (20-20-20 rule: every 20 minutes, look at something 20 feet away for at least 20 seconds).
7. **Avoid Eye Strain**: Limit activities that cause prolonged focusing on close objects, and take regular breaks to relax the eyes.
8. **Stay Active**: Engage in physical activities that promote overall health and circulation, which can benefit eye health.

These recommendations may vary based on individual cases and professional advice from healthcare providers.
Medication: Medication is used for strabismus in certain circumstances. In 1989, the US FDA approved botulinum toxin therapy for strabismus in people over 12 years old. Most commonly used in adults, the technique is also used for treating children, in particular children affected by infantile esotropia. The toxin is injected in the stronger muscle, causing temporary and partial paralysis. The treatment may need to be repeated three to four months later once the paralysis wears off. Common side effects are double vision, droopy eyelid, overcorrection, and no effect. The side effects typically resolve also within three to four months. Botulinum toxin therapy has been reported to be similarly successful as strabismus surgery for people with binocular vision and less successful than surgery for those who have no binocular vision.
Repurposable Drugs: For strabismus, a condition where the eyes do not properly align with each other, some repurposable drugs include:

1. **Botulinum Toxin (Botox)**: Originally used for cosmetic purposes, it can temporarily paralyze certain muscles, helping to realign the eyes.
2. **Cholinergic Agonists**: Drugs like pilocarpine, used for glaucoma, may be used to stimulate eye muscles.
3. **Baclofen**: Typically used as a muscle relaxant and antispastic agent, it has potential for treating certain types of strabismus by relaxing eye muscles.

These drugs may serve as adjunct therapies but are not replacements for conventional treatments like corrective lenses, vision therapy, or surgery. Always consult with a healthcare provider for appropriate diagnosis and treatment options.
Metabolites: Strabismus, also known as crossed eyes, is a condition where the eyes do not properly align with each other when looking at an object. Metabolites are not directly related to the diagnosis or primary cause of strabismus. The condition is usually associated with the muscles or nerves controlling eye movement, rather than metabolic abnormalities.
Nutraceuticals: Nutraceuticals are products derived from food sources that offer additional health benefits beyond basic nutritional value. For strabismus, there is no strong evidence to support the use of any specific nutraceuticals in correcting or managing the condition. Strabismus generally requires medical interventions such as corrective lenses, vision therapy, or surgery.

Nanotechnology (nan), involving the manipulation of materials at the molecular scale, shows potential in various medical fields, but its application in the treatment of strabismus is not well-established. Research is ongoing, and future developments may reveal more about its potential uses in ophthalmology. However, the current standard treatments for strabismus remain more conventional methods.
Peptides: Strabismus, commonly known as crossed eyes, is a visual disorder where the eyes do not properly align with each other when looking at an object. Peptides have emerging applications in various medical treatments, including potential roles in eye diseases, but their direct application to strabismus treatment is still under research. Nanotechnology (nan) has shown promise in ophthalmology for drug delivery and diagnostics, which could potentially benefit strabismus management through more effective treatments and monitoring tools. However, traditional treatments like corrective glasses, eye patches, and surgery remain the primary methods for managing strabismus.