Optical blur on the retina of eye

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The two directions of the research are A) to study the eye's optics in normal and abnormal development; B) to image, in the retina, proteins associated with neuron damage as markers of age-related changes. Aims in this period are to: A1) determine how optical components alter with eye length, to bring the eye into focus; A2) analyze optical signals to eye growth during defocus; A3) quantify which central and peripheral retinal signals to defocus can be sampled by the cone cell mosaic; B1) confirm which and in what morphologies, protein deposits are present in older, ex vivo retinas; B2) measure the interaction of the deposits with polarized light and their spectroscopic signatures and B3) develop in vivo imaging and detection methods that differentiate these proteins.******During normal eye growth and in response to defocus induced by lenses, the eye's length, optics and molecular signals change, decreasing defocus blur. We will study changes during growth towards best focus in response to changes in rearing conditions. The retina responds to optical signals to the two directions of defocus and adjusts eye growth but these signals are not understood. We will analyze the differences in candidate signals with the amount of blur and sign of defocus and will define the signals which could be "seen" by retinal cells. We will also study the subsequent molecular signals to growth. It's important to understand the optical and molecular signalling in normal growth because abnormal growth and nearsightedness (myopia) occur when signals are disrupted. Myopia is increasing worldwide (eg affecting 96% of urban teenagers in Korea). We will also gain better insight into why outdoor exposure is protective against myopia and how novel corrective lenses slow its progression. ******In our eye development study, we will use adaptive optics to correct optical blur of the eye, allowing us to resolve cone photoreceptor cells in the retina. Our imaging with polarized light has improved the visibility of deposits of one protein (amyloid beta) in the retina at the rear of the eye. We will confirm that other protein aggregates increase in number with age in the retina. These misfolded proteins form ordered fibrils which are also likely to become visible in polarized light. We will study different protein types in ex vivo retinas using polarimetry to quantify their interactions with light. Spectroscopic signatures will also be analyzed to develop an in vivo method of differentiating the proteins. These deposits may partially explain age related decreases in visual function and could give insight into the increased risk of neurodegenerative disorders with age. Imaging them in the retina, as markers of deposits in the brain, would provide a new class of diagnostics of neuron damage, much less invasive and less costly than brain imaging.********