title: Sensitivity and specificity of short-duration transient visual evoked potentials (SD-tVEP) in discriminating normal from glaucomatous eyes.
abstract: OBJECTIVE
  To evaluate the ability of the short-duration transient visual evoked potential (SD-tVEP) to discriminate between healthy eyes and eyes with early to advanced glaucomatous visual field loss.
  
  
  METHODS
  We tested 30 eyes of 30 healthy controls and 45 eyes of 35 glaucoma patients. Normal eyes had 20/30 or better visual acuity and normal 24-2 Swedish interactive thresholding algorithm (SITA) Standard visual fields. Glaucoma was staged as mild (mean deviation, MD > -6.0 dB), moderate (MD between -6.0 and -12.0 dB), and severe (MD < -12.0 dB). There were 15 eyes in each group. SD-tVEPs were recorded using the Diopsys NOVA-LX System. Each eye was stimulated with a low (Lc) and a high (Hc) Michelson contrast checkerboard pattern. Each test resulted in an Lc and an Hc SD-tVEP response. Each response was evaluated for overall waveform quality, P100 latency, and P100 amplitude referenced to the N75. The sensitivity, specificity, negative predictor value (NPV), and positive predictor value (PPV) were calculated.
  
  
  RESULTS
  Lc latency showed the highest accuracy for discrimination using receiver operating characteristic curves for high and low contrast parameters. The analysis for all subjects resulted in a 91.1% sensitivity, 93.3% specificity, 95.3% PPV, and an 87.5% NPV. Evaluating the mean Lc latency of the mild, moderate, and severe glaucoma patients against controls showed discrimination consistent with the glaucoma severity.
  
  
  CONCLUSIONS
  Short-duration transient VEP objectively identified decreased visual function and discriminated between healthy and glaucomatous eyes, and also showed good differentiation between healthy eyes and those with early visual field loss. VEP may be useful for early diagnosis of glaucoma.
authors.affiliation: Einhorn Clinical Research Center, New York Eye and Ear Infirmary, New York, NY 10003, USA.
authors.forename: Cinthi
authors.initials: C
authors.lastname: Pillai
authors.forename: Robert
authors.initials: R
authors.lastname: Ritch
authors.forename: Peter
authors.initials: P
authors.lastname: Derr
authors.forename: Alberto
authors.initials: A
authors.lastname: Gonzalez
authors.forename: Laurie
authors.initials: L
authors.lastname: Kopko Cox
authors.forename: John
authors.initials: J
authors.lastname: Siegfried
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Liebmann
authors.forename: Celso
authors.initials: C
authors.lastname: Tello
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D004568:Electrodiagnosis / Q000379:methods* / Q000592:standards; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D011930:Reaction Time / Q000502:physiology; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*