Retinal Reflectometry is a technique that uses the light returning from the retina, through the pupil (generally), to infer the properties and functions of the retina. In a sense all retinal imaging is a form of retinal reflectometry, but I restrict the term to cases where we use the actual quantitative amount of light returning to make inferences. I have collaborated extensively with both Ann Elsner and Francois Delori for reflectometric measurements, and as such, some of the work I mention here actually comes from their labs. We have sections on photoreceptor alignment reflectometry, polarization, lens and macular pigment, and retinal imaging.
Just as the Stiles Crawford effect (the variation in sensitivity of the eye depending on the angle light hits the retina) reveals the orientation of the cones, so does the reflection of light from the retina. We used this phenomenon to study cone alignment and variations in alignment.
We have used polarization as both a way to probe and separate components of the retinal light return and as a way to extract extra information from the retina. Thus, we have shown using photoreceptor alignment reflectometry (PAR) that the cone component of light returning from the retina is highly polarization preserving. As such in imaging, you can use a form of polarization imaging to look at only multiply scattered light (the depolarized light) and improve visibility of drusen and other subretinal structured. To do this we used custom approaches to analyze data from a GdX retinal imaging system. This same analysis also allows separation of components that are birefringent, revealing the pattern of Henle fiber layers, even in eyes with atrophy. By applying this to AO imaging we also showed an improvement of cone contrast.
Working with Francois Delori I helped get better estimates of crystalline lens density and macular pigment absorption and with Ann Elsner we looked at the relation between macular pigment distributions and cone pigment distributions
Ann Elsner started her retinal imaging lab to use the newly invented SLO to investigate the retina. I worked with her on some of her innovations in using IR imaging, polarization, and multiply scattered light imaging to separate out different properties of the retina in order to improve contrast. She also developed an imaging retinal densitometer which I cover elsewhere