Eyes that do not move in the same direction at the same time are
called misaligned eyes. Misaligned eyes may be either present at birth or
caused by disease or injury.
Babies' eyes are sometimes slightly misaligned until about age 3 to 4
months, when they usually begin to track normally. Misaligned eyes that persist
after age 6 months should be evaluated by a doctor. Misaligned
eyes that occur after an injury or nervous system problem (stroke or seizure)
may mean a serious problem.
Most of the focusing power in the eye occurs along the front surface, at the cornea (the clear 'window' in the front of the eyeball), or within the lens, which sits behind the cornea inside the eye. The ideal cornea has a symmetrically curved surface, like a basketball. Astigmatism is caused by a cornea or a lens that is not symmetrical, like a football.
The cornea is the transparent window in front of the colored part of the eye. It bends (refracts) light rays to focus the light onto the retina...