title: A new pattern electroretinogram paradigm evaluated in terms of user friendliness and agreement with perimetry.
abstract: OBJECTIVE
  To assess ease of use of the pattern electroretinogram optimized for glaucoma screening (PERGLA) paradigm by a novice operator; to study test-retest variability of the PERGLA parameters; and to compare results from the PERGLA to those from perimetry.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Twelve healthy control subjects and 16 patients with moderate to advanced glaucoma in at least 1 eye.
  
  
  METHODS
  Pattern electroretinograms were recorded simultaneously from both eyes using a commercially available testing station. Each participant underwent PERGLA procedures in 2 sessions. One eye of each subject was tested on contrast sensitivity perimetry (CSP) in which a 0.4 cycles/degree Gabor patch served as a stimulus. Central visual fields results from conventional automated perimetry (CAP) were obtained from patients' records. Bland-Altman analysis was performed on PERGLA results to assess normal test-retest variability. Differences from mean normal (in decibels [dB]) were compared for PERGLA versus CSP and CAP.
  
  
  METHODS
  Pattern electroretinogram amplitude, noise, phase, and test-retest variability (coefficient of variation); contrast sensitivity from CSP; perimetric sensitivity from CAP; and differences from mean normal for PERGLA, CSP, and CAP.
  
  
  RESULTS
  The mean log amplitude (0.08+/-0.12 log muV) and the mean phase (1.92+/-0.07 pi rad) for the control group were consistent with published PERGLA norms, as was test-retest variability for both amplitude (coefficient of variation [CV] = 8.2+/-7.0%) and phase (CV = 1.1+/-0.9%). The mean signal-to-noise ratio (8.7+/-4.5) was lower than published norms. The test-retest variability increased as PERGLA log amplitude decreased (R2>0.12, P<0.05). On average, differences from mean normal were similar for PERGLA versus CSP and for PERGLA versus CAP (mean differences<0.5 dB) with 95% confidence intervals near +/-4 dB in both comparisons.
  
  
  CONCLUSIONS
  A novice operator successfully replicated published PERGLA norms in a young control group for amplitude, phase, and repeatability. Higher test-retest variability was found in eyes with smaller signals. On average, PERGLA results were in reasonable agreement with those from perimetry, although there existed large individual differences which may limit the usage of PERGLA in screening or in following progression of glaucoma.
authors.affiliation: State University of New York, State College of Optometry, New York, New York 10036, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Yang
authors.forename: William H
authors.initials: WH
authors.lastname: Swanson
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D015350:Contrast Sensitivity; D004596:Electroretinography / Q000379:methods*; D005188:False Negative Reactions; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology; D012680:Sensitivity and Specificity; D014786:Vision Disorders / Q000175:diagnosis*; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields