Our research aims to understand the link between the activity of individual neurons and behavior. The retina is a very favorable place for this pursuit. It is the only element of the central nervous system visible from outside the human body and is the source of the majority of computations responsible for normal functioning vision – fine spatial resolution, color and motion. We study the functional mechanisms by which retinal photoreceptors and their ensuing visual pathways mediate these most fundamental aspects of vision and how these visual capacities are affected by blinding retinal diseases.

To achieve this, our research group works at a broad interface of biomedical engineering, neuroscience and ophthalmology to develop tools that enable the visualization of the structure and function of retinal cells at unprecedented spatial scales. The backbone of the methods pursued is a technology called adaptive optics – the same tool used by astronomers to peer at small objects in space. It turns out that the eye’s optics – the cornea and lens – blur the light that falls on and scatters from the retina.The spatial scale of this blur far exceeds the size of a single photoreceptor, ultimately preventing the stimulation and imaging of the retina at cellular resolutions.

Using adaptive optics, we can overcome the optical imperfections that exist in the human eye and gain access to the retina of living humans and animal models, much in the same manner that excised tissue has been routinely interrogated in biology and medicine ex vivo.  Most excitingly, the ability to noninvasively probe living retinal cells in diseased human eyes at high resolution opens the door to study more sensitive biomarkers for early disease diagnosis, thoroughly monitor disease progression and determine the efficacy of treatments.

Human trichromatic cone mosaic (in pseudocolor) imaged with an adaptive optics scanning laser ophthalmoscope.

In vivo image of a human cone photoreceptor mosaic. Bright circular spots are cone photoreceptors, darker areas are shadows of blood vessels.