title: Quantitative Intraoperative Torsional Forced Duction Test.
abstract: OBJECTIVE
  We developed a method for quantifying intraoperative torsional forced ductions and validated the new test by comparing patients with oblique dysfunction and controls.
  
  
  METHODS
  Comparative case series.
  
  
  METHODS
  We studied 33 eyes with oblique dysfunction (9 with presumed congenital superior oblique palsy [SOP], 13 with acquired SOP, 7 with Brown syndrome, and 4 with inverted Brown syndrome) and 31 controls. We also studied 6 eyes after superior oblique (SO) disinsertion and 2 eyes after inferior oblique (IO) disinsertion.
  
  
  METHODS
  Under deep general anesthesia, the 12 and 6 o'clock positions at the limbus were marked and the globe was maximally excyclorotated and incyclorotated without retroplacement until the first resistance was felt, and the angle of rotation (in degrees) was read on a Mendez ring by the surgeon. A photograph was taken in each position to be read by a masked observer.
  
  
  METHODS
  Maximal excyclorotation and maximal incyclorotation in each oblique dysfunction and in controls by both surgeon's report and photographic assessment. We duplicated the photographs to evaluate test-retest reliability and to evaluate agreement between the surgeon's assessments and the photographic assessment.
  
  
  RESULTS
  Surgeon's assessment revealed greater maximal excyclorotation in eyes with presumed congenital SOP than in controls (median, 40 vs. 30 degrees). Maximal excyclorotation in eyes with acquired SOP was similar to that in controls (30 degrees in both). Eyes with Brown syndrome and inverted Brown syndrome had lower maximal excyclorotation than in controls (10 and 20 vs. 30 degrees, respectively). Maximal incyclorotation in eyes with inverted Brown syndrome was lower than in controls (12.5 vs. 30 degrees), whereas it was similar to that of controls in eyes with presumed congenital SOP, acquired SOP, and Brown syndrome (30 degrees in each condition). Median maximal excyclorotation after SO disinsertion was 62.5 degrees, and maximal incyclorotation after IO disinsertion was 60 degrees. Photographic assessment yielded findings essentially identical to the surgeon's report. Test-retest reliability of the photographic reading was excellent, and agreement between the surgeon's report and the photographic reading was also excellent (95% limits of agreement, 4.4 and 11.6; intraclass correlation coefficient, 0.97 and 0.82, respectively).
  
  
  CONCLUSIONS
  The new torsional forced duction test enables quantitative assessment of SO and IO tightness and laxity.
authors.affiliation: Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota; Department of Ophthalmology, Pusan National University, Yangsan Hospital, Yangsan, Korea.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Jung
authors.affiliation: Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota. Electronic address: holmes.jonathan@mayo.edu.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Holmes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000732:Androstanols / Q000008:administration & dosage; D002648:Child; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009467:Neuromuscular Depolarizing Agents / Q000008:administration & dosage; D015835:Ocular Motility Disorders / Q000175:diagnosis*; D009801:Oculomotor Muscles / Q000187:drug effects; D010781:Photography / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D000077123:Rocuronium; D013390:Succinylcholine / Q000008:administration & dosage; D020432:Trochlear Nerve Diseases / Q000151:congenital / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D000732:Androstanols; D009467:Neuromuscular Depolarizing Agents; D013390:Succinylcholine; D000077123:Rocuronium