Horizontal Strabismus: Causes, Symptoms, and Treatment

What is Horizontal Strabismus?

Horizontal strabismus, also known as "crossed eyes" or "lazy eye," refers to a condition where one or both eyes are misaligned horizontally. In this condition, one eye may turn inward (esotropia) or outward (exotropia), while the other remains in a straight position. This misalignment can occur intermittently or constantly and can affect vision if left untreated.

Causes of Horizontal Strabismus

• Genetics. Strabismus often runs in families, suggesting a genetic predisposition. Children born with strabismus may inherit a tendency for eye misalignment.
• Eye Muscle Imbalance. The condition occurs when the muscles that control eye movement are not working together properly. This imbalance can cause one eye to turn inward or outward.
• Neurological Issues. Damage or disruption to the nerves controlling the eye muscles (such as in cases of stroke, brain injury, or neurological disorders) can result in horizontal strabismus.
• Refractive Errors. Severe farsightedness (hyperopia) or astigmatism can cause the eyes to misalign, leading to strabismus. The eyes may have difficulty focusing properly, which can result in turning to compensate for the refractive errors.
• Premature Birth. Babies born prematurely have a higher risk of developing strabismus due to underdeveloped eye muscles or neurological issues.
• Trauma. Injury to the eyes or brain can affect the muscles responsible for controlling eye movement, leading to strabismus.
• Health Conditions. Conditions like cerebral palsy, Down syndrome, and other developmental disorders can increase the risk of strabismus, as they affect muscle coordination and nerve function.

Symptoms of Horizontal Strabismus

• Misaligned Eyes. The most obvious symptom is the visible misalignment of the eyes, either with one eye turning inward (esotropia) or outward (exotropia).
• Double Vision. In some cases, the brain may receive conflicting visual signals from the misaligned eyes, resulting in double vision (diplopia).
• Poor Depth Perception. Individuals with horizontal strabismus may experience difficulty judging distances or perceiving depth accurately, as both eyes are not working together to form a clear, unified image.
• Amblyopia (Lazy Eye). If strabismus is not treated in children, the brain may begin to ignore the input from the misaligned eye, leading to amblyopia (a condition where one eye becomes functionally weaker than the other).
• Eye Strain or Fatigue. Individuals with strabismus may experience eye strain, headaches, or fatigue due to the effort of trying to focus or compensate for the misalignment.

Treatment for Horizontal Strabismus

• Glasses or Lenses. Prescription glasses or lenses may be used to correct refractive errors, such as farsightedness or astigmatism, which contribute to the strabismus.
• Vision Therapy. Vision therapy exercises can help strengthen the eye muscles, improve coordination, and retrain the brain to use both eyes together effectively.
• Patching. For children, patching the stronger eye may be recommended to encourage the weaker eye to work harder and develop better vision. This is often used in conjunction with vision therapy.
• Surgical Correction. In cases where non-surgical treatments are ineffective, surgery may be necessary to realign the eye muscles. The procedure involves adjusting the strength of the muscles that control eye movement.
• Botox Injections. In some cases, botulinum toxin (Botox) injections may be used to temporarily weaken specific eye muscles, helping to realign the eyes and improve function.