title: Optical Coherence Tomography Angiography of Peripapillary Retinal Blood Flow Response to Hyperoxia.
abstract: OBJECTIVE
  To measure the change in peripapillary retinal blood flow in response to hyperoxia by using optical coherence tomography (OCT) angiography.
  
  
  METHODS
  One eye of each healthy human participants (six) was scanned with a commercial high-speed (70 kHz) spectral OCT. Scans were captured twice after 10-minute exposures to normal breathing (baseline) and hyperoxia. Blood flow was detected by the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. Peripapillary retinal blood flow index and vessel density were calculated from en face maximum projections of the retinal layers. The experiment was performed on 2 separate days for each participant. Coefficient of variation (CV) was used to measure within-day repeatability and between-day reproducibility. Paired t-tests were used to compare means of baseline and hyperoxic peripapillary retinal blood flow.
  
  
  RESULTS
  A decrease of 8.87% ± 3.09% (mean ± standard deviation) in flow index and 2.61% ± 1.50% in vessel density was observed under hyperoxia. The within-day repeatability CV of baseline measurements was 5.75% for flow index and 1.67% for vessel density. The between-day reproducibility CV for baseline flow index and vessel density was 11.1% and 1.14%, respectively. The between-day reproducibility of the hyperoxic response was 3.71% and 1.67% for flow index and vessel density, respectively.
  
  
  CONCLUSIONS
  Optical coherence tomography angiography with SSADA was able to detect a decrease in peripapillary retinal blood flow in response to hyperoxia. The response was larger than the variability of baseline measurements. The magnitude of an individual's hyperoxic response was highly variable between days. Thus, reliable assessment may require averaging multiple measurements.
authors.affiliation: Casey Eye Institute Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: Alex D
authors.initials: AD
authors.lastname: Pechauer
authors.affiliation: Casey Eye Institute Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: Yali
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Casey Eye Institute Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: Liang
authors.initials: L
authors.lastname: Liu
authors.affiliation: Casey Eye Institute Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: Simon S
authors.initials: SS
authors.lastname: Gao
authors.affiliation: Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, People's Republic of China.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Casey Eye Institute Oregon Health & Science University, Portland, Oregon, United States.
authors.forename: David
authors.initials: D
authors.lastname: Huang
mesh_terms: D000328:Adult; D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology; D005260:Female; D005451:Fluorescein Angiography; D005583:Fourier Analysis; D006801:Humans; D018496:Hyperoxia / Q000503:physiopathology*; D008297:Male; D012039:Regional Blood Flow / Q000502:physiology; D015203:Reproducibility of Results; D012160:Retina / Q000503:physiopathology*; D012171:Retinal Vessels / Q000502:physiology*; D041623:Tomography, Optical Coherence / Q000379:methods*