Dissociated vertical divergence: a righting reflex gone wrong.
Dissociated vertical divergence (DVD) is an ocular motor disorder characterized by a slow, upward drift of 1 eye when the other eye is fixating a target. I propose that DVD is a dorsal light reflex in which asymmetrical visual input to the 2 eyes evokes a vertical divergence movement of the eyes. This primitive visuo-vestibular reflex functions as a righting response to restore vertical orientation in lower lateral-eyed animals by equalizing binocular visual input. The dorsal light reflex is suppressed in humans but can manifest as DVD when early-onset strabismus precludes normal binocular development.
Brodsky
M C
MC
Department of Ophthalmology, University of Arkansas for Medical Sciences, Little Rock, USA.
D000818:Animals; D005133:Eye Movements; D006801:Humans; D008027:Light; D015835:Ocular Motility Disorders / Q000209:etiology* / Q000503:physiopathology; D009801:Oculomotor Muscles / Q000503:physiopathology; D012021:Reflex, Abnormal; D012025:Reflex, Pupillary; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology; D015357:Vision Disparity / Q000502:physiology; D015348:Vision, Binocular / Q000502:physiology