Retinal capillary oximetry with visible light optical coherence tomography

Area of Science:

• Ophthalmology
• Physiology
• Biomedical Engineering

Background:

• Assessing retinal oxygen saturation (sO2) is crucial for understanding retinal metabolism but remains challenging.
• Previous methods focused on major retinal vessels, limiting detailed capillary analysis.
• Visible-light optical coherence tomography (OCT) has been used for retinal oximetry in rats.

Purpose of the Study:

• To extend oximetry measurements to retinal capillaries.
• To investigate oxygen saturation across all three retinal vascular plexuses.
• To assess the potential of OCT capillary oximetry for studying retinal circulation and diseases.

Main Methods:

• Amplifying and extracting spectroscopic signals from individual capillary segments.
• Utilizing optical coherence tomography (OCT) angiography for guidance and signal extraction.
• Measuring capillary sO2 in the retinal circulation of rats under varying oxygen conditions.

Main Results:

• Successfully measured capillary sO2 in the rat retinal circulation.
• Demonstrated reproducibility and validated measurements in superficial capillaries.
• Determined sO2 responses to hypoxia and hyperoxia in different retinal capillary beds.

Conclusions:

• OCT capillary oximetry is a viable technique for measuring oxygen saturation in retinal capillaries.
• This method provides new insights into retinal oxygen metabolism and circulation.
• OCT capillary oximetry holds potential for advancing the study of normal and diseased retinal vasculature.