title: Intraocular pressure lowering is associated with an increase in the photopic negative response (PhNR) amplitude in glaucoma and ocular hypertensive eyes.
abstract: OBJECTIVE
  The aim of our study was to determine whether IOP lowering in glaucomatous and ocular hypertensive (OHT) eyes leads to an improvement in the full-field photopic negative response (PhNR) of the electroretinogram.
  
  
  METHODS
  A prospective nonrandomized interventional cohort study was conducted. Patients with OHT or glaucomatous optic neuropathy were recruited, and photopic full-field electroretinograms (ERG) were performed at baseline and then repeated 1 to 2 months later. The change in PhNR amplitude was compared between those eyes that had a significant lowering in IOP (defined as >25% decrease from baseline or to a predetermined target IOP) during follow-up and those that did not.
  
  
  RESULTS
  From a cohort of 30 eyes, 18 eyes had a significant reduction in IOP during follow-up (n = 18) and 12 eyes had no significant change in IOP (<25% reduction in IOP, n = 12). A significant increase in PhNR amplitude and the PhNR/b-wave amplitude ratios was observed in the reduced IOP group, but not in the IOP stable group for the two flash intensities used (2.25 and 3.00 cd.s/m(2)).
  
  
  CONCLUSIONS
  The full-field PhNR amplitude provides a potentially reversible measure of inner retinal function that improves after IOP lowering. Further study now is required to assess its use as a measure of optic nerve health in glaucoma patients.
authors: Centre for Eye Research Australia, University of Melbourne, Melbourne, Victoria, Australia. nuwan.niya@doctors.org.uk
authors: Nuwan
authors: N
authors: Niyadurupola
authors: Chi D
authors: CD
authors: Luu
authors: Dan Q
authors: DQ
authors: Nguyen
authors: Kristen
authors: K
authors: Geddes
authors: Gary X V
authors: GX
authors: Tan
authors: Celestine C W
authors: CC
authors: Wong
authors: Tu
authors: T
authors: Tran
authors: Michael A
authors: MA
authors: Coote
authors: Jonathan G
authors: JG
authors: Crowston
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D055253:Color Vision; D004596:Electroretinography; D005260:Female; D005500:Follow-Up Studies; D005901:Glaucoma / Q000188:drug therapy / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D009901:Optic Nerve Diseases / Q000209:etiology / Q000503:physiopathology*; D010775:Photic Stimulation; D011446:Prospective Studies; D012165:Retinal Ganglion Cells / Q000502:physiology*; D014794:Visual Fields
chemical_list: D000959:Antihypertensive Agents