title: Operator learning effect and interoperator reproducibility of the scanning laser polarimeter with variable corneal compensation.
abstract: OBJECTIVE
  To ascertain operator learning effect, and to quantify the interoperator reproducibility, using the newly introduced GDx VCC (variable corneal compensator) scanning laser polarimeter.
  
  
  METHODS
  Prospective instrument validation study.
  
  
  METHODS
  Three operators with no prior experience in operating the GDx VCC examined one randomly chosen eye of each of 30 randomly ordered subjects (15 glaucoma patients and 15 normal subjects).
  
  
  METHODS
  Each study eye was scanned by the 3 operators in a random sequence during a single session. Five GDx parameters were analyzed: TSNIT (temporal, superior, nasal, inferior, temporal) Average, TSNIT Standard Deviation (SD), Superior Average, Inferior Average, and Nerve Fiber Indicator (NFI).
  
  
  METHODS
  Retinal nerve fiber layer (RNFL) thickness GDx parameters across operators.
  
  
  RESULTS
  A learning effect was not found for any of the operators for any of the 5 GDx parameters studied. Reproducibility for each GDx parameter was measured as the mean SD value of the measurements taken by the 3 operators. Interoperator reproducibilities for normal and glaucomatous eyes, respectively, were 0.8 and 1.6 microm (TSNIT Average), 1.7 and 2.2 microm (Superior Average), 1.6 and 2.7 microm (Inferior Average), 1.3 and 1.7 microm (TSNIT SD), and 1.4 and 4.6 microm (NFI). The data obtained by each operator were highly correlated with those of the other 2 operators.
  
  
  CONCLUSIONS
  With the commercially available GDx VCC, a learning effect was not found for 3 novice operators. In addition, RNFL measurements seem highly reproducible across operators.
authors.affiliation: Department of Ophthalmology, Hebrew University-Hadassah Medical Center, Jerusalem, Israel.
authors.forename: Shahar
authors.initials: S
authors.lastname: Frenkel
authors.forename: Efrat
authors.initials: E
authors.lastname: Slonim
authors.forename: Amjad
authors.initials: A
authors.lastname: Horani
authors.forename: Michal
authors.initials: M
authors.lastname: Molcho
authors.forename: Israel
authors.initials: I
authors.lastname: Barzel
authors.forename: Eytan Z
authors.initials: EZ
authors.lastname: Blumenthal
mesh_terms: D000328:Adult; D000368:Aged; D001718:Birefringence; D003315:Cornea / Q000502:physiology; D003952:Diagnostic Imaging / Q000295:instrumentation*; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006282:Health Personnel / Q000193:education*; D006801:Humans; D007834:Lasers; D007858:Learning; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D015588:Observer Variation; D009885:Ophthalmology / Q000193:education; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*