Hyperspectral Imaging for Measurement of Oxygen Saturation in the Optic Nerve Head

Abstract

Hyperspectral imaging can be adapted to measure and map relative oxygen saturation in retinal structures and the ONH in nonhuman primate eyes.

Enhanced Oxygen Saturation in Optic Nerve Head of Non-Human Primate Eyes Following the Intravitreal Injection of NCX 434, an Innovative Nitric Oxide-Donating Glucocorticoid

“…Oxygen saturation was determined at 7, 14, 21, 31, and 41 days postdosing in various ONH areas according to previously published protocols. 13 …”

“…Further, glucocorticoids, by increasing intraocular pressure (IOP), might further reduce oxygen availability to critical structures in the eye. 12,13 Nitric oxide (NO) is produced by 3 distinct isoforms of nitric oxide synthase (NOS). Two of these are constitutive enzymes (neuronal NOS or NOS-I and endothelial NOS or NOS-III) requiring intracellular Ca ++ accumulation and are expressed in many cell types within the ocular compartment, 14 whereas the third isoform (NOS-II or iNOS) is mainly expressed in immune cells, is induced in response to pro-inflammatory stimuli, and produces large amounts of NO in a Ca ++ -independent manner.…”

“…More specifically, a noninvasive hyperspectral imaging technique, in conjunction with specialized algorithms to compute blood saturation values, has been shown to reliably map relative values of oxygen saturation in the retina and optic disc under physiological conditions 25,26 and in response to elevated IOP or oxygen breathing in a nonhuman primate model. 13 Here, using a hyperspectral imaging system, we have compared the effect of NCX 434 an NO-donating TA to that of the reference TA on oxygen saturation of the ONH and overlying arteries and veins in the cynomolgus monkey model. Concomitantly, we also monitored the effects of these treatments on IOP.…”

Novel, Noninvasive Multispectral Snapshot Imaging System to Measure and Map the Distribution of Human Retinal Vessel and Tissue Hemoglobin Oxygen Saturation

“…Khoobehi [8] and Beach [9] have previously adapted non-invasive hyperspectral imaging, which is an advanced type of spectral imaging, for recording oxygen saturation data from the primate retina. This technique, in conjunction with specialized algorithms to compute blood oxygen saturation values, was able to map relative values of saturation over the retina and optic disc.…”

“…An imaging spectrograph and a digital camera were used to obtain hyperspectral images. Khoobehi [8] used images with 512 spatial points and 256 spectral bands for sufficient light sensitivity and spectral resolution to monitor oxygen-dependent spectral changes in vessels. Each frame of the resulting data cube contains the spatial (x) and spectral (λ) axes for each line of the image.…”