Eric Logean and Chris Dainty
The retina is a thin layer of neural cells, located at the posterior pole of the eye. It is part of the central nervous system and its role is to detect, process and send the visual information to the brain. In-vivo observations of the eye fundus reveal large anatomical features such as the retinal vasculature and the optic disc. Hints of the presence of the retina is found in specular reflections from the inner-limiting membrane and from light scattered from nerve fibre bundles. Except for the cone photoreceptors, images of individual neural cells of the retina have not been reported yet, the difficulty being their great transparency to light.
Transparent objects interact with the phase of light transmitted through them. This effect is generally not observed because photo-detectors are sensitive to the intensity of light and not to the phase. The goal of this work is to find a technique to visualise phase structures within the living human retina. With, as far reaching prospective, to be able to observe the different neural cells of the retina and follow at the cellular level the progression of degenerative diseases such as glaucoma.