ISSUE HIGHLIGHT

Optometric vision therapy for nonstrabismic accom-modative and vergence disorders involves highly spe-cific, sequential, sensory-motor-perceptual stimulation paradigms and regimens. It incorporates purposeful, con-trolled, and scientifically based manipulations of target blur, disparity, and proximity, with the aim of normalizing the accommodative system, the vergence system, and their mutual interactions.1-3 In addition, other sources of sensory information, such as kinesthesia4 (e.g., touching the near test object) and audition5,6 (e.g., oculomotor auditory biofeedback) correlated to the accommodative and vergence states (e.g., position, innervation, effort, etc.) can provide cue rein-forcement. Inclusion of related behavioral modification par-adigms,7-9 such as general relaxation,5 visual imagery,10,11 (e.g., “think far or near”), and attentional shaping12 may help one learn to initiate (i.e., provide a “trigger ” mechanism) and/or enhance the appropriate motor responses. However, the ultimate goal of optometric vision therapy is not simply to impact positively on various aspects of the oculomotor sys-tem per se, in isolation, but to attain clear and comfortable binocular vision at all times. It involves oculomotor inte-gration with the head (i.e., eye-head coordination),13 neck (i.e., proprioceptive information),14 limbs,15 and overall body,16,17 with information from the other sensory modal-ities, producing temporally efficient, coordinated behavior18,19 within a context of harmonious spatial sense16,17,20 under a variety of external and internal conditions and states. Prevalence of nonstrabismic accommodative and vergence disorders Nonstrabismic accommodative and vergence disorders of a non-organic, nonpathological nature (i.e., “functional ” in origin) are the most-common ophthalmic vision conditions (other than refractive error) that present in the general opto-The scientific basis for and efficacy of optometric vision therapy in nonstrabismic accommodative and vergence disorder