Twelve subjects with functional strabismic amblyopia were tested for aniseikonia under conditions of normal binocular viewing. Controls consisted of ten subjects with normal binocular single vision and ten with alternating strabismus and no amblyopia. A polarizing filter haploscope "direct visual comparison" eikonometer was used. In comparison with the controls, the amblyopic group showed a small degree of aniseikonia, averaging 0.3%. In the majority of these subjects, the amblyopic eye "perceived" the target pattern as being smaller than the identical target pattern "perceived" by the normal eye.