title: Electrophysiological ON and OFF Responses in Autosomal Dominant Optic Atrophy.
abstract: OBJECTIVE
  To assess the effect of autosomal dominant optic atrophy (ADOA) on ON and OFF retinal ganglion cell (RGC) function by evaluating the ON and OFF components of the photopic negative response (PhNR).
  
  
  METHODS
  Twelve participants from six families with OPA1 ADOA and 16 age-matched controls were recruited. Electrophysiological assessment involved pattern ERGs (PERGs), focal (20°) and full-field long-duration (250 ms) flash ERGs using a red light-emitting diode flash on a rod-saturating blue background, and full-field brief (300 μs) xenon flash ERGs using a red filter over a continuous rod saturating blue background. Amplitudes and implicit times of the ERG components were analyzed and the diagnostic potential of each electrophysiological technique was determined by generating receiver operating characteristic (ROC) curves.
  
  
  RESULTS
  Mean amplitudes of the N95 and all PhNRs, except the full-field PhNRON, were significantly reduced in participants with ADOA (P < 0.01). Subtraction of the group-averaged focal ERG of ADOA participants from that of controls showed an equal loss in the focal PhNRON and PhNROFF components, whereas in the full-field ERG the loss in the PhNROFF was greater than that in the PhNRON component. The areas under the ROC curve (AUC) for the focal PhNRON (0.92), focal PhNROFF (0.95), and full-field PhNROFF (0.83), were not significantly different from that of the PERG N95 (0.99).
  
  
  CONCLUSIONS
  In patients with ADOA, the PhNRON and PhNROFF components are nearly symmetrically reduced in the long-duration ERG, suggesting that ON- and OFF-RGC pathways may be equally affected.
authors.affiliation: School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.
authors.forename: Enyam Komla A
authors.initials: EK
authors.lastname: Morny
authors.affiliation: School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.
authors.forename: Tom H
authors.initials: TH
authors.lastname: Margrain
authors.affiliation: Division of Optometry and Visual Sciences, City University, London, United Kingdom.
authors.forename: Alison M
authors.initials: AM
authors.lastname: Binns
authors.affiliation: School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom 3Eye Unit, University Hospital of Wales, Cardiff, United Kingdom.
authors.forename: Marcela
authors.initials: M
authors.lastname: Votruba
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004596:Electroretinography; D005260:Female; D020558:GTP Phosphohydrolases / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D029241:Optic Atrophy, Autosomal Dominant / Q000235:genetics / Q000503:physiopathology*; D010775:Photic Stimulation; D012160:Retina / Q000473:pathology / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*
chemical_list: D020558:GTP Phosphohydrolases; C415198:OPA1 protein, human