title: Quadrant pattern ERG with SLO stimulation in normals and glaucoma patients.
abstract: BACKGROUND
  The pattern ERG (PERG) is one of the promising methods for investigation of glaucoma and may detect it at an early stage. The purpose of this study was to test the usefulness of the scanning laser ophthalmoscope (SLO) as a stimulator for evoking quadrant PERGs under visual control in normal and glaucoma eyes.
  
  
  METHODS
  The helium-neon laser of a Rodenstock SLO was used for quadrant stimulation (18 degrees x 29 degrees pattern size), while an infrared laser visualized the eye's fundus. Steady-state pattern-reversal ERGs were recorded in response to stripe patterns (8.33 Hz, 0.5 cycles/deg) in four retinal quadrants. Corresponding visual field defects were determined with the Octopus perimeter (G1, peridata). The subjects were 28 controls and 34 glaucoma patients with visual field losses and papillometric defects.
  
  
  RESULTS
  Amplitudes of nasal retinal areas (which include the blind spot) are smaller than those of temporal ones, and temporal lower responses are the largest. PERG amplitudes of all quadrants are significantly reduced in glaucoma (sensitivity 82%, specificity 80%). The differences between upper and lower quadrant PERGs are correlated with the differences between localized visual field defects of the same areas, (r = 0.46, P = 0.02).
  
  
  CONCLUSIONS
  The study demonstrates the feasibility of the SLO system for evoking localized PERG in normals and patients and shows the reduction of quadrant ERG amplitudes in glaucoma using the laser system.
authors.affiliation: Department of Ophthalmology, University of Erlangen-Nürnberg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Horn
authors.forename: C
authors.initials: C
authors.lastname: Mardin
authors.forename: M
authors.initials: M
authors.lastname: Korth
authors.forename: P
authors.initials: P
authors.lastname: Martus
mesh_terms: D000328:Adult; D004596:Electroretinography / Q000379:methods; D005074:Evoked Potentials, Visual; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D007834:Lasers; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation / Q000295:instrumentation*; D015203:Reproducibility of Results; D012160:Retina / Q000502:physiology*; D014794:Visual Fields