Non-concomitant or Paralytic Squint
This subdivision of manifest squint occurs when there is a deviation of the eye in different directions. The causes for non-concomitant squint are lesions of the cranial nerve that supply the eye muscle or a lesion of the muscle itself. The symptoms are diplopia in the direction of action of the paralyzed muscle, vertigo, and nausea. The signs include deviation of eye in paralyzed muscle, greater secondary than primary angle of deviation, restriction of eye movement, normal visual acuity, compensatory head tilt, and false orientation. Non-concomitant squintis diagnosed through patient history, head posture, ocular position, cover test, ocular movement, and a diplopia test. It can be treated by occlusion of affected eye, vitamin B addition, and operation.