title: Preliminary investigation of multispectral retinal tissue oximetry mapping using a hyperspectral retinal camera.
abstract: Oximetry measurement of principal retinal vessels represents a first step towards understanding retinal metabolism, but the technique could be significantly enhanced by spectral imaging of the fundus outside of main vessels. In this study, a recently developed Hyperspectral Retinal Camera was used to measure relative oximetric (SatO2) and total hemoglobin (HbT) maps of the retina, outside of large vessels, in healthy volunteers at baseline (N = 7) and during systemic hypoxia (N = 11), as well as in patients with glaucoma (N = 2). Images of the retina, on a field of view of ∼30°, were acquired between 500 and 600 nm with 2 and 5 nm steps, in under 3 s. The reflectance spectrum from each pixel was fitted to a model having oxy- and deoxyhemoglobin as the main absorbers and scattering modeled by a power law, yielding estimates of relative SatO2 and HbT over the fundus. Average optic nerve head (ONH) saturation over 8 eyes was 68 ± 5%. During systemic hypoxia, mean ONH saturation decreased by 12.5% on average. Upon further development and validation, the relative SatO2 and HbT maps of microvasculature obtained with this imaging system could ultimately contribute to the diagnostic and management of diseases affecting the ONH and retina.
authors.affiliation: École Polytechnique de Montréal, Institut de génie biomédical, Département de Génie électrique, 2900, boul. Édouard-Montpetit, Montréal, Qc, H3T 1J4, Canada. Electronic address: midesjardins@ucsd.edu.
authors.forename: Michèle
authors.initials: M
authors.lastname: Desjardins
authors.affiliation: Optina Diagnostics, 3900 boul. Cote-Vertu, Suite #220, St-Laurent, Qc, H4R 1V4, Canada.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Sylvestre
authors.affiliation: Optina Diagnostics, 3900 boul. Cote-Vertu, Suite #220, St-Laurent, Qc, H4R 1V4, Canada.
authors.forename: Reza
authors.initials: R
authors.lastname: Jafari
authors.affiliation: University of Toronto, Department of Ophthalmology and Vision Sciences, Toronto Western Hospital, 399 Bathurst Street, Toronto, On, M5T 2S8, Canada.
authors.forename: Susith
authors.initials: S
authors.lastname: Kulasekara
authors.affiliation: University of Toronto, Department of Ophthalmology and Vision Sciences, Toronto Western Hospital, 399 Bathurst Street, Toronto, On, M5T 2S8, Canada.
authors.forename: Kalpana
authors.initials: K
authors.lastname: Rose
authors.affiliation: Université de Montréal, Département d'ophtalmologie, 2900 Boulevard Édouard-Montpetit, Montréal, Qc, H3T 1J4, Canada.
authors.forename: Rachel
authors.initials: R
authors.lastname: Trussart
authors.affiliation: Université de Montréal, Département d'ophtalmologie, 2900 Boulevard Édouard-Montpetit, Montréal, Qc, H3T 1J4, Canada.
authors.forename: Jean Daniel
authors.initials: JD
authors.lastname: Arbour
authors.affiliation: University of Toronto, Department of Ophthalmology and Vision Sciences, Toronto Western Hospital, 399 Bathurst Street, Toronto, On, M5T 2S8, Canada; University of Waterloo, School of Optometry and Vision Science, 200 University Ave W, Waterloo, On, N2L 3G1, Canada.
authors.forename: Chris
authors.initials: C
authors.lastname: Hudson
authors.affiliation: École Polytechnique de Montréal, Institut de génie biomédical, Département de Génie électrique, 2900, boul. Édouard-Montpetit, Montréal, Qc, H3T 1J4, Canada. Electronic address: frederic.lesage@polymtl.ca.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lesage
mesh_terms: D000328:Adult; D005901:Glaucoma / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D016014:Linear Models; D009898:Optic Disk / Q000502:physiology*; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000378:metabolism*; D012039:Regional Blood Flow / Q000502:physiology; D012171:Retinal Vessels / Q000502:physiology*; D055815:Young Adult
chemical_list: D006454:Hemoglobins; D010100:Oxygen
keywords: Hypoxia; Optic disc; Optic nerve head; Retinal oximetry; Spectral imaging; Total hemoglobin content