Strabismus
Strabismus (sometimes called crossed, lazy, or wandering eye) is a disorder of the eyes involving a lack of coordination between the muscles of the eyes. Essentially, the eyes do not point in the same direction. This prevents bringing the gaze of each to the same point in space, preventing proper binocular vision, which in turn adversely affects depth perception.When strabismus is congenital or develops in infancy, it can cause amblyopia, or "lazy eye," in which the brain ignores input from the deviated eye although it is capable of normal sight. (Since strabismus can cause lazy eye, it is sometimes itself inaccurately referred to as 'lazy eye'.)
Strabismus may be constant or intermittent. Types of strabismus include:
- esotropia, or one eye turning inward;
- exotropia, or one eye turning outward;
- hypertropia, or one eye turning upward.
Early treatment of strabismus in infancy can prevent the development of amblyopia and depth perception problems. However, this requires that the surgery place the eyes in perfect alignment. Eyes that remain misaligned can still develop visual problems, even though the misalignment is lessened. This makes surgery impractical for minor cases of strabismus. Prism lenses can also be used to provide some comfort for sufferers, and to prevent double vision from occurring. However, it does not cure the condition.
In adults with previously normal alignment, the onset of strabismus usually results in double vision.
In addition to the visual problem, strabismus can be considered a cosmetic problem owing to the appearance of the deviated eye:
In a recent study of adult strabismus patients, 85 percent reported that they had problems with work, school and sports because of their strabismus. In the same study, 70 percent said it had a negative effect on their self-image. Fifty percent rated their eye alignment problem as moderate or severe and they reported being anxious and depressed. [1]
A mild strabismus