title: Dorsal midbrain syndrome with loss of motor fusion: a rare association.
abstract: BACKGROUND
  Dorsal midbrain syndrome (DMS) is characterized by upgaze paralysis, convergence-retraction nystagmus, and eyelid retraction. Impaired downgaze and pupillary light-near dissociation may co-exist, while less common features including exotropia and convergence paralysis have also been described. However, loss of motor fusion is not a well recognised finding in DMS.
  
  
  OBJECTIVE
  To describe DMS associated with loss of motor fusion.
  
  
  METHODS
  Retrospective case series.
  
  
  RESULTS
  Five patients (age 21-80 years) presented with features of DMS due to severe head injury (n=1), brainstem stroke (n=3) and pinealoma (n=1). All five complained of constant diplopia with horizontal and vertical separation and had an exotropia (range 20Δ to 70Δ), absent convergence and motor fusion. Two underwent strabismus surgery and subsequently had a variable improvement in their motor fusion. The remaining three patients were managed with occlusion.
  
  
  CONCLUSIONS
  This case series illustrates the complexity of ocular motility findings associated with DMS and highlights the potential difficulties in the management of patients with loss of motor fusion.
authors.affiliation: Tennent Institute of Ophthalmology, Gartnavel General Hospital, Glasgow, UK. mgregory1@nhs.net
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Gregory
authors.forename: Mamun Q
authors.initials: MQ
authors.lastname: Rahman
authors.forename: Marie
authors.initials: M
authors.lastname: Cleary
authors.forename: Clifford R
authors.initials: CR
authors.lastname: Weir
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001927:Brain Diseases / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D001930:Brain Injuries / Q000150:complications; D001932:Brain Neoplasms / Q000150:complications; D020526:Brain Stem Infarctions / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D008636:Mesencephalon / Q000473:pathology*; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000175:diagnosis / Q000209:etiology; D015835:Ocular Motility Disorders / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D010870:Pineal Gland / Q000473:pathology; D010871:Pinealoma / Q000150:complications; D012189:Retrospective Studies; D055815:Young Adult