Eye Deceases

(H49-H50) Strabismus

What is Strabismus

Vision defect that affects the ability of the eye to focus and coordinate on movements on objects is known as strabismus. Eyes that are not aligned normally or eye that have asymmetrical views are considered to be faulty. These types of disorders are often associated with squint, crossed eye, heterotropia and walleye. If strabismus is not treated on time, then it can worsen the condition and the person may suffer from permanent blindness.

ICD-10 H49. – H50.
ICD-9 378
OMIM 185100
DiseasesDB 29577
MedlinePlus 001004
MeSH D013285

Causes of Strabismus

In a few cases, when the eye is not able to focus properly, it can be a result of a problem in the eye muscles which controls the movement of the eye and this is caused by strabismus. When there’s a problem in the brain, it also results in strabismus and in this case the brain is unable to fuse two images that it receives from the eye. In rare cases, it may lead to a tumor that affects the visual ability.  Children also experience strabismus and it can be treated by wearing glasses. It is also suspected that strabismus can also be hereditary.

Symptoms of Strabismus

There are many symptoms related to strabismus. The symptoms depend on the misalignment of the eye and people suffering from strabismus face problems in judging distances or focusing on objects or experience blurred or double vision.  Detecting symptoms if the first thing to known if strabismus needs treatment like surgery. The most common symptom is crossed eye, single eye that tilts to the right, left, up or down. In this condition, the eye is not able to focus properly on an object and coordinate movements. Squinting is one of the symptoms of strabismus.

Strabismus Types

Depending on the disrupted vision, strabismus can be of different types. After the doctors has diagnosed, an appropiate treatment can be suggested for strabismus. If any of the eye or eyes are not able to coordinate properly, this condition is known as constant strabismus. If this problem occurs in specific periods, it is known as intermittent. When both the eyes turn inward which results in crossed eyes is known as esotropia.

In a similar way if the eye turns outward rather than inward, it is known as exotropia. Another type of strabismus is hypertropia in which the vision is symmetrical with excess orientation upwards in one or both eyes. Another type of strabismus is known as Duane’s Syndrome in which the eye cannot make normal movements away from the nose.

Strabismus Treatment

There are different ways of treating strabismus which can start from the simplest by eyeglasses to complex therapy and surgery. People suffering from intermittent strabismus can wear special glasses, eye patches and go for vision therapy. After a while, this helped the brain to take control on the eye movements and surgery can be avoided.  Children with constant strabismus, surgery can be the best option but there is no guarantee that it would get improved and it very often last for a long time.

Strabismus Classification

Paralytic Strabismus

  • Third (oculomotor) nerve palsy
  • Fourth (trochlear) nerve palsy
    • Congenital fourth nerve palsy
  • Sixth (abducent) nerve palsy
  • Total (external) ophthalmoplegia
  • Progressive external ophthalmoplegia
  • Other
    • Kearns-Sayre syndrome

Other Strabismus

Other forms of strabismus include:

  • Convergent concomitant/Divergent concomitant
    • Esotropia
    • Exotropia
  • Vertical strabismus
    • Hypertropia
    • Hypotropia
  • Other and unspecified heterotropia
    • Microtropia
    • Monofixation syndrome
  • Heterophoria
    • Esophoria
    • Exophoria
  • Mechanical strabismus
    • Brown's sheath syndrome
  • Other
    • Duane syndrome