National Eye Institute 2R01EY005253-39

Neuronal mechanisms of image processing in the early visual pathway

This award funds research to understand how ON and OFF visual pathways process images in the early visual system, with a focus on their role in myopia development. The project aims to measure neuronal and visual function differences in humans with myopia and normal vision using advanced electrophysiological and imaging techniques.

Description

Images captured by our eyes are processed in the retina by separate ON and OFF pathways that signal light and dark stimuli in visual scenes. The traditional thinking is that the two pathways converge in visual cortex and their responses blend with eye movements, making it difficult to separate ON and OFF pathway function. Our recent work and preliminary results challenge this traditional view by demonstrating that ON and OFF pathways remain segregated in visual cortex, are differently modulated by the luminance contrast and spatiotemporal properties of stimuli, and their function can be measured in the clinic from visual responses to the onset of light and dark stimuli. Our work indicates that the different stimulus preferences from ON and OFF pathways are needed to sample the diverse light and dark stimuli in our visual world, but they also make ON pathways more vulnerable than OFF pathways to low light and scenes that lack bright surfaces. Low light and lack of outdoor vision are major risk factors in myopia, a visual disorder that blurs vision at far distance and is increasing globally. We hypothesize that myopia emerges from under-stimulation of ON visual pathways. We will test this by measuring neuronal and visual function mediated by ON and OFF pathways in humans with myopia and normal vision, using electroretinography, electroencephalography, automated photography, and new visual tests with head-mounted displays and wearable eye tracking.

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