title: Diagnostic occlusion test in cases of unilateral strabismus sursoadductorius.
abstract: OBJECTIVE
  To investigate the diagnostic occlusion test (OT) according to Marlow in strabismus sursoadductorius (StS; also known as 'unilateral superior oblique palsy') and its implications for surgical treatment.
  
  
  METHODS
  In 67 cases of StS, angles of strabismus were measured before and after patching the affected eye for three days. Horizontal, vertical and torsional deviations were measured in front of the tangent screen of Harms in nine directions of gaze.
  
  
  RESULTS
  After OT, most cases of StS showed the following distribution of vertical deviation (VD) on horizontal versions: setting the VD in 30 degrees adduction to 100%, VD in primary position (PP) was 50%, VD in abduction 14%, excyclotropia in PP about 40% of the amount of VD. Those StS-cases showing the same distribution of VD on horizontal versions before and after OT were called 'typical' ones (27% of the patients). However, 73% of the patients showed a different distribution before OT: 68% VD in PP, 36% VD in abduction, excyclotropia of 20% in PP. After OT these cases converted to the normal pattern described above: VD in PP was 53 % and VD in 30 degrees abduction was 19%, excyclotropia in PP was 36%.
  
  
  CONCLUSIONS
  In 'typical' StS-cases, OT is not necessary. 'Atypical' cases, however, can be converted into 'typical' ones: they get more incomitant VD on horizontal versions and greater excyclotropia in PP. As VD in adduction remains almost the same in both groups after OT, surgery can be based on the angle in adduction. In individual 'atypical' patients the amount of oblique muscle surgery has to be modified after OT.
authors.affiliation: Department of Strabismology & Neuro-Ophthalmology, University Eye Clinic, Heidelberg, Germany. gerold_kolling@med.uni-heidelberg.de
authors.forename: G H
authors.initials: GH
authors.lastname: Kolling
authors.forename: H
authors.initials: H
authors.lastname: Steffen
authors.forename: A
authors.initials: A
authors.lastname: Baader
authors.forename: K
authors.initials: K
authors.lastname: Unnebrink
mesh_terms: D003941:Diagnostic Techniques, Ophthalmological; D006801:Humans; D009801:Oculomotor Muscles / Q000473:pathology; D012189:Retrospective Studies; D012683:Sensory Deprivation; D013285:Strabismus / Q000175:diagnosis*; D020432:Trochlear Nerve Diseases / Q000175:diagnosis*