title: Photopic negative response versus pattern electroretinogram in early glaucoma.
abstract: OBJECTIVE
  Photopic negative response (PhNR) and pattern electroretinogram (PERG) are electrophysiological markers of retinal ganglion cell function; both are reduced in glaucoma. We compared PhNR and PERG in different stages of the disease.
  
  
  METHODS
  Eleven eyes with preperimetric glaucoma (glaucomatous optic disc with normal field); 18 with manifest glaucoma; and 26 normals were included. We obtained PhNR (flash strength from 0.1-4 cd·s/m(2)) and steady-state PERG and analyzed PhNR amplitude (baseline to 72 ms trough); PhNR/b-wave ratio; PERG amplitude; and PERG ratio (0.8°/16°).
  
  
  RESULTS
  Identification of PhNR structure was only reliable ≥1 cd·s/m(2) flash strength; amplitude and receiver operating characteristics (ROC) area under curve (AUC) changed little from 1 to 4 cd·s/m(2). Both PhNR and PERG (amplitude and ratio) were reduced in preperimetric and more so in manifest glaucoma. AUCs based on PhNR/PERG amplitudes were not significantly different from chance in preperimetric glaucoma (AUCs 0.61/0.59), but were significant in manifest glaucoma (0.78/0.76); ratios were significant in both glaucoma groups (0.80/0.73 and 0.80/0.79). In spite of that, PhNR ratio and PERG ratio were not significantly correlated (r = 0.22 across all groups); an ROC based on a combination of both reached AUCs of 0.85/0.90 for preperimetric/manifest glaucoma.
  
  
  CONCLUSIONS
  Both PhNR and PERG performed similarly to detect glaucoma; for both, ratios performed better than amplitudes. The PhNR has the advantage of not requiring clear optics and refractive correction; the PERG has the advantage of being recorded with natural pupils.
authors: Section Visual Function, Department of Ophthalmology, University of Freiburg, Germany.
authors: Dunja
authors: D
authors: Preiser
authors: Wolf A
authors: WA
authors: Lagrèze
authors: Michael
authors: M
authors: Bach
authors: Charlotte M
authors: CM
authors: Poloschek
mesh_terms: D000368:Aged; D003941:Diagnostic Techniques, Ophthalmological / Q000592:standards*; D018450:Disease Progression; D042241:Early Diagnosis; D004596:Electroretinography / Q000379:methods / Q000592:standards; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000175:diagnosis / Q000503:physiopathology; D010775:Photic Stimulation / Q000379:methods; D011680:Pupil / Q000502:physiology; D012372:ROC Curve; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000502:physiology*; D012680:Sensitivity and Specificity; D014794:Visual Fields / Q000502:physiology*