INDUCED SIZE EFFECT WITH THE EYES IN ASYMMETRIC CONVERGENCE

When the eyes are turned in order to observe an object to the right or to the left of the median plane at near vision, the images of that object in the two eyes may be different in size because the distance from one eye is greater than that from the other eye. The smaller image would be expected in the eye that turns nasally, since the object is farther from that eye. The results of a number of different experiments, 1 however, provide evidence that some type of change in the relative sizes of the ocular images may occur when the eyes are turned in asymmetric convergence ; this change offsets, or tends to offset, the difference in the sizes of the retinal images which would exist because of the difference in the distance of the object from the two eyes. This apparent change was investigated for visual distances of