Near infrared adaptive optics flood illumination retinal angiography

Elena Gofas-Salas (1, 2) , Pedro Mecê (1) , Laurent Mugnier (1) , Aurélie Montmerle Bonnefois (1) , Cyril Petit (1) , Kate Grieve (2, 3) , José Sahel (3, 2, 4) , Michel Paques (2, 3) , Serge Meimon (1)

1 DOTA, ONERA, Université Paris Saclay (COmUE) [Palaiseau]
2 Institut de la Vision
3 CHNO - Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts
4 University of Pittsburgh School of Medicine

Image-based angiography is a well-adapted technique to characterize vasculature, and has been used in retinal neurovascular studies. Because the microvasculature is of particular interest, being the site of exchange between blood and tissue, a high spatio-temporal resolution is required, implying the use of adaptive optics ophthalmoscopes with a high frame rate. Creating the opportunity for decoupled stimulation and imaging of the retina makes the use of near infrared (NIR) imaging light desirable, while the need for a large field of view and a lack of distortion implies the use of a flood illumination-based setup. However, flood-illumination NIR video sequences of erythrocytes, or red blood cells (RBC), have a limited contrast compared to scanning systems and visible light. As a result, they cannot be processed via existing image-based angiography methods. We have therefore developed a new computational method relying on a spatio-temporal filtering of the sequence to isolate blood flow from noise in low-contrast sequences. Applying this computational approach enabled us to perform angiography with an adaptive optics flood illumination ophthalmoscope (AO-FIO) using NIR light, both in bright-field and dark-field modalities. Finally, we demonstrate the capabilities of our system to differentiate blood flow velocity on a retinal capillary network in vivo.

Domaines: Imagerie

Elena Gofas-Salas, Pedro Mecê, Laurent Mugnier, Aurélie Montmerle Bonnefois, Cyril Petit, et al.. Near infrared adaptive optics flood illumination retinal angiography. Biomedical optics express, 2019, 10 (6), pp.2730. ⟨10.1364/BOE.10.002730⟩. ⟨hal-02173202⟩