Journal of Eye and Vision

Nystagmus is a condition that causes involuntary, rapid movement of one or both eyes. Nystagmus often occurs with vision problems, including blurriness. This condition is sometimes called “dancing eyes”.

There are three basic kinds of strabismus: Esotropia, Exotropia and Hypertropia, depending on which direction the eyes are deviated.

Esotropia
The most common type of strabismus is esotropia, which occurs when either one or both eyes turn in toward the nose. Some children are born with this condition. More frequently, it starts at about age 2 1/2. When esotropia occurs in these older children, eyeglasses can often help to treat the condition by correcting the childs vision for farsightedness or hyperopia.

Hypertropia
Hypertropia is the least common type of strabismus. In this condition, one eye is higher than the other. As a result, the child often tilts or cocks his or her head to one side to get rid of the double vision that this problem frequently causes.

Exotropia
Exotropia is the second most common kind of strabismus. In this condition, one or both eyes turn out. It usually starts at age two or three. In the beginning, the eye may drift out only for a few seconds when the child is tired or ill. It typically occurs when the child looks far away. Closing one eye in bright sunlight when playing outside is also a common early sign.