Abnormal ocular movements in amblyopia.

The visual afferent pathways affect the oculogyric centres in two ways: (1) By maintaining the oculomotor tonus; (2) By inducing optically elicited movements. In organic amblyopia the diminution of central visual acuity is not sufficient to impair the oculomotor reflexes which usually remain unchanged until the vision becomes very poor. Howver, abnormal movements are typically observed in the inhibition of strabismic amblyopia. Sensorimotor difficulties are observed in both version and vergence movements. Abnormal version patterns have two main effects: suppression of optokinetic nystagmus and kinetic anarchy of pursuit and saccadic movements. Vergences are found to be much more brittle and vulnerable to amblyopia than versions, and amblyopia is often accompanied by anomalies of fusional, accommodative, and fast vergence movements.