title: Regional differences in oxygen saturation in retinal arterioles and venules.
abstract: BACKGROUND
  Retinal vessel oxygenation saturation measurements have been the focus of much attention in recent years as a potential diagnostic parameter in a number of ocular and systemic pathologies. This interest has been heightened by the ability to measure oxygen saturation in vivo using a photographic technique.
  
  
  METHODS
  Retinal vessel oxygenation in venules and arterioles of 279 retinal vessels of 12 healthy Caucasian participants (mean age: 30 SD (+/- 6) years) were measured consecutively three times to evaluate short-term variation in oxygen saturation and regional variability of retinal vessel oxygen saturation using dual-wavelength technology (Oxymetry Modul, Imedos, Germany). All subjects underwent standard optometric assessment including non-contact intra-ocular pressure assessment as well as having their systemic blood pressure measured.
  
  
  RESULTS
  Vessels were grouped as either near-macula or peripheral, depending on their location. Peripheral arterioles and venules exhibited significantly lower oxygen saturation compared to their near-macula counterparts (arterioles: 94.7% (SD 3.9) vs. 99.7% (SD 3.2); venules: 65.1% (SD 7.2) vs. 90.3% (SD 6.7)). Both arterioles and venules, main branches, and those feeding and draining the retina near the macula and periphery showed low short-term variability of oxygen saturation (arterioles: COV 1.2-1.8%; venules: COV 2.9-4.9%).
  
  
  CONCLUSIONS
  Retinal arterioles and venules exhibit low short-term variation of oxygen saturation in healthy subjects. Regional differences in oxygen saturation could be a potential useful marker for risk stratification and diagnostic purposes of area-specific retinal pathology such as age-related macula degeneration and diabetic maculopathy.
authors.affiliation: School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK. r.heitmar1@aston.ac.uk
authors.forename: Rebekka
authors.initials: R
authors.lastname: Heitmar
authors.forename: Saima
authors.initials: S
authors.lastname: Safeen
mesh_terms: D000328:Adult; D001160:Arterioles; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D016011:Normal Distribution; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D012039:Regional Blood Flow / Q000502:physiology; D012161:Retinal Artery / Q000502:physiology*; D012169:Retinal Vein / Q000502:physiology*; D014699:Venules
chemical_list: D010100:Oxygen