title: Normative values and predictors of retinal oxygen saturation.
abstract: OBJECTIVE
  To determine normal retinal oxygen saturation (SO2) values measured with retinal oximetry in a multiethnic group of healthy subjects and to evaluate the association of retinal SO2 with demographic and clinical parameters.
  
  
  METHODS
  Retinal oximetry was performed in both eyes of 61 normal healthy subjects. Global and quadrant venous (SvO2) and arterial oxygen saturation (SaO2), arteriovenous difference in SO2, and venular and arteriolar width were measured. The association of SO2 parameters with age, gender, ethnicity, refraction, iris color, history of controlled systemic hypertension, and smoking was analyzed.
  
  
  RESULTS
  Average SvO2 and SaO2 were 55.3 ± 7.1% and 90.4 ± 4.3%, respectively. All average measurements were comparable in both eyes, both genders, and among ethnic groups. Inferonasal quadrant SaO2 was higher in Asians. Age was associated with decreased SvO2 (β = -0.19; P = 0.001) and SaO2 (β = -0.11; P = 0.003). History of controlled systemic hypertension was associated with an increase in arteriovenous difference in SO2 (β = 3.99; P = 0.013).
  
  
  CONCLUSIONS
  This is the first description of retinal SO2 in healthy, multiethnic subjects. Aging decreases SvO2 and SaO2 and should be accounted for when interpreting retinal oximetry measurements. Other demographic and clinical parameters studied did not seem to significantly influence retinal SO2 measurements.
authors.affiliation: Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: Pooja D
authors.initials: PD
authors.lastname: Jani
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Mwanza
authors.forename: Kyle B
authors.initials: KB
authors.lastname: Billow
authors.forename: Alexa M
authors.initials: AM
authors.lastname: Waters
authors.forename: Sarah
authors.initials: S
authors.lastname: Moyer
authors.forename: Seema
authors.initials: S
authors.lastname: Garg
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D012016:Reference Values; D012161:Retinal Artery / Q000502:physiology*; D012169:Retinal Vein / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen