Abstract

Modification of the focusing power of the lens, oculomotor vergence, and pupil movements are all evoked in response to distance-related stimulation. These three oculomotor responses are termed the "near triad" and are driven primarily by a synergistic combination of two different, but geometrically related, stimuli: retina image disparity and retinal image blur. Failure of near triad components to interact appropriately is a common cause of clinical disorders. Accommodative esotropia is an esodeviation that occurs in patients when they use their accommodative system (1) and is thought to be the result of excessive levels of accommodative convergence (1,2,3). These high levels of accommodative vergence could be the result of increased accommodative effort due to an uncorrected hyperopia, and/or a high effective accommodative vergence to accommodative stimulus ratio (AC/AS ratio). If the excessive accommodative drive cannot be compensated by the fusional vergence system, then accommodative esotropia occurs (2,4).

© 1997 Optical Society of America