Does Strabismus Affect Vision?

Without treatment, strabismus can worsen over time.
Without treatment, strabismus can worsen over time.

Strabismus or squint is a condition in which the eyes are not aligned properly with each other. Since both eyes must point in the same direction to see properly, it ends up affecting the vision resulting in signs and symptoms, such as:

  • Double vision (seeing double images of any object)
  • Blurry vision
  • Difficulty in reading
  • Loss of depth perception (unable to judge how far or near something is)
  • Weakness in or around the eye

What causes strabismus?

There are six muscles in the eye that work in coordination with each other to bring eye movements. The problem in the functioning of these muscles or in the nerves that control these muscles is thought to be the cause of strabismus.

Strabismus is found to be caused by the following conditions:

  • Heredity (family history of strabismus)
  • Uncorrected shortsightedness
  • Uncorrected farsightedness
  • Poor vision in one eye
  • Cerebral palsy (a group of disorders occurring by birth that affects muscle tone or posture)
  • Down syndrome
  • Hydrocephalus (a condition present by birth that results in a buildup of fluid in the brain)
  • Stroke (the most common cause of strabismus in adults)
  • Head injuries (damage to the area that is concerned with the control of eye movements)
  • Graves disease (a thyroid disorder in which there is increased production of thyroid hormone
  • Disorders of the nervous system, such as myasthenia gravis
  • Brain tumors
  • Any eye surgery that can damage the eye muscles

How is strabismus treated?

After taking the medical history of the patient, the doctor discusses various treatment options with you that include:

  • Eyeglasses: These are used in patients with uncorrected refractive errors, shortsightedness, and farsightedness. These are special glasses to help focus and straighten the eyes.
  • Prism lens: This is a type of specialized lens that bends the light rays and allows the affected person to focus. They can be attached to eyeglasses or made as part of the lens.
  • Eye exercises: These are recommended for patients who have their eyes directed outwards (exotropia). Eye exercises help focus both eyes inward.
  • Medications: Medications include Atropine that can be given in the form of eye drops or ointments. The problem of the eye muscles is treated with injections of Botulinum toxin type A, such as Botox.
  • Patching: Patching aims at strengthening a misaligned eye that is weaker than the other. An eye patch is applied over the stronger eye, which forces the person to use the weaker eye resulting in the restoration of the weaker eye’s strength.
  • Eye muscle surgery: A surgery that changes the length or position of eye muscles helps in achieving the proper alignment of eyes.

What happens if strabismus is not treated?

Without treatment, strabismus can worsen over time. This is especially true for children.

Untreated strabismus may result in:

  • Lazy eye (amblyopia): Because each eye points in different directions, two images of the same object are produced. Over time, the stronger (healthy) eye amongst the two works more to produce a single image, which results in poor vision in the other (strabismus-affected) eye. Around one-third of children with strabismus end up with amblyopia.
  • Blurring of vision
  • Permanent double vision
  • Eyestrain
  • Frequent headaches
  • Low self-esteem


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