Overview
Glaucoma is sometimes called the silent thief of sight because it can be hard to notice that your field of view is getting smaller until the condition is quite far along. The sight loss happens when the cells that form the optic nerve shrink and die. But instead of vision becoming full of holes, people with glaucoma report seeing blurred patches or details missing from a whole image. This could be because parts of the brain that process vision are filling in the scene and compensating for the problem in the eye.
Findings from the team’s previous research involving people with glaucoma suggest that nerve cells in the visual parts of the brain might reorganise themselves in response to damaged retinas. If so, this could be an attempt to keep what's left of the person's vision. The team is now investigating this further in people with and without glaucoma.
Results from the study should give us more information about the role of the brain in glaucoma. They might be able to tell us something about how well the visual brain can reorganise itself in a way that helps vision in glaucoma’s early stages. They may also lead to a better way to detect glaucoma early on if what’s happening in the brain is a closer match to sight loss than can be picked up by looking for changes in the back of the eye.
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Scientific summary
Clinical strategies for early detection of glaucoma, and research into the prevention/reversal of damage have typically focussed on retinal and optic nerve changes. However, findings from psychophysical, anatomical and neuroimaging studies point to substantial remodelling in the visual cortex in response to neural (including retinal) insult. It is critical that we fully understand these changes, not just for the refinement of clinical methods for the early detection of damage but, of increasing importance, to understand the extent to which neural reorganisation in the CNS can be driven to support the recovery of visual function.
Using novel 7 Tesla functional Magnetic Resonance Imaging (fMRI) and psychophysical methods, the team is investigating changes in the visual cortex of individuals with early glaucoma, and testing their association with clinical measures of visual field damage. Findings from this study will enable a better understanding of cortical remodelling and adaptation to retinal damage, as well as a more focussed approach to the development of tests for early glaucoma and the evaluation of novel therapies for visual recovery in clinical trials.