title: Pattern electroretinograms during the cold pressor test in normals and glaucoma patients.
abstract: OBJECTIVE
  To examine the influence of the cold pressor test (CPT) on steady-state pattern electroretinograms (PERG) in healthy subjects and glaucoma patients.
  
  
  METHODS
  Steady-state PERGs to 7.8 Hz pattern reversal stimuli were recorded in 63 subjects. Fifteen healthy control subjects, 14 patients with ocular hypertension (OHT), and 34 patients with open-angle glaucoma (20 normotensive [NTG] and 14 high tension glaucoma [HTG]) were examined. Steady-state PERG amplitudes and latencies were analyzed at baseline, during cold stimulus using a modified CPT, and during the subsequent recovery phase. Blood pressure and heart rate were simultaneously recorded in 10 normals and 11 glaucoma patients.
  
  
  RESULTS
  During the three test conditions (baseline, ice water, and warm water) glaucoma patients (NTG and HTG) showed significantly reduced PERG amplitudes in comparison with control subjects (P < 0.001) and with OHT patients (P < 0.004). Patients with OHT displayed lower PERG amplitudes than control subjects (nonsignificant, with consideration of Bonferroni). Only NTG patients showed a significant effect of the CPT on PERG amplitude (significant decrease during warm water P = 0.02). Latencies shortened significantly during warm-water period after cold stimulus in control subjects (P = 0.05) and in NTG patients (P = 0.02) with a nonsignificant trend of shortened latencies in the OHT (P = 0.06) and HTG groups (P = 0.3). Systolic and diastolic blood pressure increased during cold water (P < 0.001) and decreased during warming-up conditions (P < 0.001).
  
  
  CONCLUSIONS
  This study shows that a CPT influences the PERG responses particularly in NTG. (ClinicalTrials.gov number, NCT00494923.).
authors.affiliation: Department of Ophthalmology, Friedrich-Alexander-University of Erlangen-Nuremberg, Bavaria, Germany.
authors.forename: Antonia
authors.initials: A
authors.lastname: La Mancusa
authors.forename: Folkert K
authors.initials: FK
authors.lastname: Horn
authors.forename: Jan
authors.initials: J
authors.lastname: Kremers
authors.forename: Cord
authors.initials: C
authors.lastname: Huchzermeyer
authors.forename: Michael
authors.initials: M
authors.lastname: Rudolph
authors.forename: Anselm
authors.initials: A
authors.lastname: Jünemann
mesh_terms: D003080:Cold Temperature; D004596:Electroretinography / Q000379:methods*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012160:Retina / Q000503:physiopathology; D012165:Retinal Ganglion Cells / Q000502:physiology*; D013312:Stress, Physiological
keywords: cold pressor test; glaucoma; pattern electroretinogram