In-vivo imaging of the eye’s fundus is widely used to study eye’s health. State of the art Adaptive Optics devices can resolve features up to a lateral resolution of 1.5 um. This resolution is still above what is needed to observe sub-cellular structures such as cone cells (1-1.25 um diameter). This limit in resolution is due to the small numerical aperture of the eye when the pupil is fully dilated (max 0.24).
In our work, we overcome this limit using a non-standard illumination scheme. A laser beam is shined on the lateral choroid layer, whose scattered light is illuminating the eye’s fundus. Thanks to a Spatial Light Modulator the scattered light from the choroid layer can be manipulated to produce a scanning focus spot on the fundus. The intensity of the reflected light from the fundus is collected from the pupil and used for reconstructing the image.
Dino Carpentras, Timothé Laforest, Demetri Psaltis, and Christophe Moser, "Overcoming the resolution limit in retinal imaging using the scattering properties of the sclera
(Conference Presentation)," Proc. SPIE 9717, Adaptive Optics and Wavefront Control for Biological Systems II, 971705 (Presented at SPIE BiOS: February 13, 2016; Published: 27 April 2016); https://doi.org/10.1117/12.2209559.4848767803001.
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