Developing Strategies for Three-Dimensional Imaging of Oxygen Tension in the Rodent Retina

Abstract

Insufficient oxygen delivery and retinal hypoxia have been implicated as causal in the development of many devastating diseases of the eye. While the two-dimensional imaging of retinal oxygen tension (PO₂) has now been applied in a variety of different animal models, it is fundamentally a luminescence-based system lacking depth discrimination. However, mammalian retinal tissue is nourished by two distinct vascular beds, the retinal and the choroidal vasculatures, and they are exceedingly difficult to separate using traditional two-dimensional imaging strategies. Numerous studies have demonstrated that retinal and choroidal PO₂ differ substantially. Therefore, the single PO₂ value currently returned through data analysis cannot accurately represent the separate contributions of the choroidal and retinal vasculatures to the state of retinal oxygenation. Such a separation would significantly advance our understanding of oxygen delivery dynamics in these two very distinct vasculatures. In this study, we investigate new strategies for generating separate retinal and choroidal PO₂ maps in the rodent retina using our existing phosphorescence-based lifetime imaging system.