title: The relationship between dissociated vertical divergence (DVD) and head tilts.
abstract: BACKGROUND
  Dissociated vertical divergence (DVD) has been associated with manifest head tilts. Also, DVD has been described as demonstrating a characteristic response to forced head tilt by increasing the size of the DVD on contralateral tilt.
  
  
  METHODS
  A series of 116 consecutive patients with DVD associated with infantile esotropia were examined according to a predetermined protocol between 1989 and 1994. Each patient was examined for a manifest head tilt. Also, the response of the DVD to forced ipsilateral and contralateral head tilt was analyzed. In addition, 100 consecutive patients with manifest head tilts were examined and the etiology of the tilt determined.
  
  
  RESULTS
  A manifest head tilt was present in 35% (26/74) of patients with an ocular fixation preference and no prior vertical muscle surgery. None of the patients with alternating fixation and a history of no vertical muscle surgery manifested a head tilt. Most patients responded in the classically described manner by increasing the size of the DVD on forced contralateral tilt and decreasing the size of the DVD on ipsilateral tilt. Atypical responses were not related to the presence of oblique overaction. DVD was the etiology in 9 of 100 consecutive patients with a manifest head tilt.
  
  
  CONCLUSIONS
  Patients with DVD often manifest a head tilt. Most respond by increasing the size of the DVD on forced contralateral head tilt and decreasing on ipsilateral tilt. Atypical responses did not appear to be influenced by oblique overaction. DVD is a relatively frequent cause of manifest head tilts.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison 53705-3631, USA.
authors.forename: R T
authors.initials: RT
authors.lastname: Bechtel
authors.forename: B J
authors.initials: BJ
authors.lastname: Kushner
authors.forename: G V
authors.initials: GV
authors.lastname: Morton
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005099:Exotropia / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D007223:Infant; D008297:Male; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies