Strabismus (Crossed Eyes)

In strabismus – colloquially called strabismus or silver gaze – (thesaurus synonyms: Alternating strabismus; Heterophoria (latent strabismus); Heterotropia (manifest strabismus); Hypertropia (elevation strabismus); Hypotropia (downward strabismus); Congenital strabismus; Coordination disorder of eye muscles; Nonparalytic strabismus; Ocular muscle insufficiency; Strabismus convergens (inward strabismus); Strabismus divergens (outward strabismus); Cyclotropia (rolling strabismus); ICD-10 H50. 9 – Strabismus, unspecified) is the strabismus of the eye. It is an expression of a disturbance of the eye muscle balance, which leads to a misalignment of both eyes.

A distinction is made between latent strabismus (heterophoria) and manifest strabismus (heterotropia). Heterophoria is a muscle balance disorder of both eyes, which only becomes apparent under certain circumstances, such as stress, fatigue or alcohol consumption. This disorder is compensated or balanced by a mechanism of binocular vision (fusion). There are different forms of heterophoria (latent strabismus) defined by the direction of the deviation:

  • Esophoria (deviation to the nose).
  • Exophoria (deviation to the temple)
  • Hyperphoria (deviation upwards)
  • Hypophoria (deviation downward)
  • Cyclophoria (rolling strabismus; depending on the direction Inzyklophorie or exzyklophorie).

Heterotropia is a permanent and permanent deviation of one eye from a common direction of gaze.

There are several forms of heterotropia (manifest strabismus), defined by the direction of deviation:

  • Strabismus convergens or esotropia (deviation toward the nose; inward or internal strabismus).
  • Strabismus divergens or exotropia (deviation to the temple; outward or external strabismus).
  • Strabismus verticalis or hypertropia (deviation upward; height strabismus) or hypotropia (deviation downward; downward strabismus).
  • Strabismus rotatorius or cyclotropia (rolling strabismus; depending on the direction incyclotropia or excyclotropia).

One can distinguish the accompanying strabismus from the paralytic strabismus. Concomitant strabismus (strabismus concomitans; nonparetic strabismus) refers to the inability of the eye muscles to direct both lines of vision to the same point. The coordination of the eyes (one or alternately both eyes) is disturbed. In this case, the squint angle is always approximately the same in all directions of gaze. This is not the case in paralytic strabismus (paretic strabismus).

There are different forms of strabismus concomitans:

  • Strabismus concomitans convergens (ICD-10 H50.0).
  • Strabismus concomitans divergens (ICD-10 H50.1)
  • Intermittent strabismus concomitans (ICD-10 H50.3)

Frequency peak: Strabismus concomitans (concomitant strabismus) occurs before the age of two years. The prevalence (disease frequency) of heterophoria is about 70% (in Central Europe). The prevalence of heterotropia is 6% (in Central Europe). The prevalence of strabismus concomitans is up to 7 % (in Central Europe).

Course and prognosis: Without treatment of strabismus concomitans (concomitant strabismus), amblyopia (defective vision) manifests in the squinting eye, which may lead to unilateral blindness. If strabismus is suspected or in families with strabismus, a baby should be presented to an ophthalmologist as early as 6 to 12 months of age! Amblyopia is treated by covering the correctly seeing eye with a patch (occlusion treatment; masking bandage, eye patch). This causes the eye with poorer vision to be encouraged.