Strabismus

That condition inwhich the eyes are not parallel for distantvision. The visual axis of one eye only is di- rected towards the object looked at; this is known as the fixing eye, while the other is known as the deviating eye. It is caused byanything which develops preponderance ofpower in a muscle, either directly or indirectly.It may be due to an uncorrected error of re-fraction; or from anything which preventsbinocular vision, such as cataract, corneal opacities, displaced macula lutea, a short, long, orparalyzed muscle.

Source: Ophthalmic Dictionary including pronunciation, derivation and definition of the words used in Optometry and Ophthalmology by James J. Lewis, Oph. D. Professor of Optometry in the Northern Illinois College of Ophthalmology and Otology, Chicago.