Submitted by Thiruvelan on Fri, 06/25/2010

Crossed eye or strabismus is mistakenly considering by many as Lazy eye or Amblyopia, but amblyopia and strabismus are different.

The confusion between these two conditions may be because a cross eye can cause lazy eye. In other words, a constant unilateral crossed eye (strabismus) can cause lazy eye (amblyopia). However, infrequent crossed eye (strabismus occurs rarely) may rarely cause lazy eye.

Strabismus crossed eye

Strabismus crossed eyes is a condition of both eyes do not look at the same place at the same time. It occurs when an eye turns in, out, up or down and is usually causing by poor eye muscle control or a high amount of farsightedness.

There are six muscles attached to every eye that control how it moves. The muscles receive signals from the brain that instructs their movements. Normally, the eyes work together so they both point at the same place. When there is any problem develops with eye movement control, then an eye may turn in, out, up, or down. The eye turning may occur more frequently or may appear only at certain conditions such as when the person is tired, ill, or has done a lot of reading or close work. In some cases, the same eye may turn each time, while in other cases, the eyes may alternate turning.

A proper eye alignment is important to avoid seeing double vision, for good depth perception, and to prevent the development of poor vision in the turned eye. When the eyes are misaligned, the brain receives two different images. At first, this may create double vision and confusion, but over time, the brain will learn to ignore the image from the turned eye. If the eye turning becomes constant (frequent) and is not treated properly, it can lead to permanent vision reduction in one eye, a condition called amblyopia or lazy eye.

Some baby’s eyes may appear to misaligns, but are actually both aim at the same object. This is a condition called pseudo-strabismus or false strabismus. The appearance of crossed eyes may be due to extra skin that covers the inner corner of the eyes, or a wide bridge of the nose. Usually, this will change as the child's face begins to grow.

Strabismus usually develops in infants and young children, mostly at the age of three, but older children and adults can also develop the condition. There is a common misconception that a child with strabismus will outgrow the condition, but this is not true. Actually, strabismus may become worse without proper treatment. Any child older than four months whose eyes do not appear to be straight all the time should examine for strabismus.

Strabismus types or classification

  • Inward turning known as esotropia
  • Outward turning known as exotropia
  • Upward turning known as hypertropia
  • Downward turning known as hypotropia

Other classifications of strabismus include:

  • The frequency with which it occurs - either constant or intermittent
  • It always involves the same eye (only one eye) - unilateral
  • It involves both eyes (right eye or sometimes left eye) - alternating.