Retinal Oxygen Saturation in Patients with Primary Open-angle Glaucoma Using a Non-flash Hypespectral Camera

Area of Science:

• Ophthalmology
• Medical Imaging
• Physiology

Background:

• Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness.
• Retinal hypoxia and altered blood flow are implicated in glaucoma pathogenesis.
• Non-invasive assessment of retinal oxygen saturation (SO2) can provide insights into disease mechanisms.

Purpose of the Study:

• To investigate differences in retinal vessel blood oxygen saturation (SO2) between patients with POAG and healthy controls.
• To explore the relationship between POAG severity and retinal SO2.
• To evaluate the utility of hyperspectral retinal imaging in glaucoma research.

Main Methods:

• A novel non-flash hyperspectral retinal camera was used to image 22 POAG patients and 17 healthy controls.
• Retinal SO2 was measured at specific wavelengths (548-610 nm) in arterioles and venules.
• POAG patients were categorized into mild-moderate and moderate-severe groups based on visual field mean deviation (MD).

Main Results:

• No significant differences in arteriolar SO2 or arteriovenous (AV) SO2 difference were found between POAG patients and controls.
• Venular SO2 was significantly higher in POAG patients with MD ≥ -6 dB compared to controls and mild glaucoma patients (p = 0.005).
• AV SO2 differences were significantly lower in patients with more severe visual field defects (p = 0.006).

Conclusions:

• Elevated venular SO2 in advanced POAG may indicate reduced oxygen consumption, potentially linked to ganglion cell degeneration.
• Retinal vessel SO2 measurements, particularly venular, show promise as a biomarker for glaucoma severity.
• Hyperspectral imaging offers a valuable tool for assessing retinal hemodynamics in ocular diseases.