Amblyopic contrast sensitivity: insensitivity to unsteady fixation.

Functional amblyopia (a typically unilateral loss of visual acuity of unknown origin) is frequently accompanied by unsteady fixation. Measurements taken under conditions of retinal-image stabilization indicate that this fixation problem does not contribute to the currently measured losses in spatial contrast sensitivity of the amblyopic eye. Indeed, retinal image motions recorded from unsteadily fixating eyes do not produce spatial contrast sensitivity losses when superimposed on the central field of a normal subject, indicating that such losses are not an immediate consequence of unsteady fixation.