Steady-state accommodation as a function of sinusoidal and square-wave grating contrast was measured in amblyopes. The amblyopic eyes exhibited reduced average response levels and required greater contrast to sustain accommodation than the fellow dominant eye or the eyes of visually-normal control subjects. Following therapy, accommodation in the amblyopic eye markedly improved. These results suggest: reduced accommodative controller gain, reduced stimulus effectiveness of target contrast, and considerable residual visual system plasticity with respect to the neurological control pathways of accommodation, in the amblyopic eye.