The Advanced Retinal Imaging Alliance focuses its research on nine primary projects to develop systems and techniques used to better understand the physiology, structure and function of the human eye. These projects are spear-headed by teams of ARIA faculty, students, and expert research scientists and engineers with extensive experience, who develop entirely new technologies necessary to advance adaptive optics imaging development. ARIA's primary projects are:

TWO-PHOTON IMAGING OF THE RETINA: Using infrared wavelengths to excite fluorophores with minimum visual stimulation for functional imaging. Two-photon fluorescence imaging has a number of advantages for retinal imaging. Our group was the first to demonstrate two-photon imaging in the living primate eye (Hunter et al, 2011).
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IN VIVO RETINAL PHOTOTOXICITY STUDY: We have discovered two new and unexpected effects on the primate retina caused by prolonged exposure to bright visible light (Morgan et al, 2008). The observed effects are autofluorescence (AF) photobleaching and, at higher light levels, retinal pigment epithelium (RPE) disruption. These effects raise interesting questions about how light interacts with the retina and if they are ultimately deleterious for the eye (Hunter et al, 2012).
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HIGH-RESOLUTION PHOTOPIGMENT DENSITOMETRY: Photopigment densitometry has been applied to the study of retinal function for over 60 years. With the advent of near diffraction-limited ophthalmoscopes that can resolve individual photoreceptors, it is possible to apply this technique to investigations that require high spatial localization.
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BLOOD FLOW: Neurovascular Coupling, Hemodynamic Imaging, Imaging Pericytes.
We are developing AOSLO technology to objectively report capillary blood flow by imaging the movement of single blood cells as they flow through the capillary network. This direct and non-invasive assessment of retinal blood flow provides structural and functional information on the vascular network of the retina. We are pursuing several projects in this area: 1) examining the role of capillary level neurovascular coupling in the central nervous system 2) characterizing flow and structure parameters that describe normal vascular perfusion and 3) exploring whether aberrant blood flow patterns can serve as a preclinical biomarker of early stages of retinal disease.
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GANGLION CELL FUNCTION: Dr. Merigan's research examines the role of retinal ganglion cells in the visual perception of primate (human and macaque) and mouse. Although the retina contains more than 17 types of ganglion cell and each type forms a complete mosaic across the retina, little is known about what role each type plays in seeing. In collaboration with David Williams and Jennifer Hunter, Dr. Merigan is studying the role of different ganglion cell types using adaptive optics imaging of their calcium response.
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HUMAN RETINAL DISEASES: Adaptive optics imaging is a state of the art technology especially suited for non-invasive imaging of the human eye. Individual cells in multiple layers of the retina can be imaged through the dilated pupil. This technology can be used to discover the earliest indicators of retinal disease, follow disease progression over time and to provide quicker endpoints when studying the efficacy of treatments in clinical trials.
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OPTIC NEURITIS: Optic neuritis results from inflammation of the optic nerve, the bundle of neurons that transmits visual information from the retina to the brain. This inflammation can disrupt the flow of information to the brain causing abrupt and severe vision loss. Optic neuritis can be caused by many different diseases of the eye and nervous system. Swelling of the optic nerve head, a condition called papilledema, is monitored clinically using conventional ophthalmic imaging techniques, such as color fundus photography. With advanced retinal imaging techniques with adaptive optics, we can visualize changes to individual nerve fiber bundles, which are composed of several axons. These individual nerve fiber bundles exit the eye at the optic nerve head and form the optic nerve. This work aims to develop a more sensitive metric of the health of nerve fibers in the living eye and has the potential to be used to evaluate the efficacy of treatments in patients with optic neuritis.
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Center for Visual Science University of Rochester