Measuring residual visual function after cerebral damage - a potential path for optimising rehabilitation approaches

The integrity of the visual field can be assessed using clinical techniques such as perimetry that rely on subjective report, or can be quantified objectively using functional magnetic resonance imaging (fMRI). In the case of central lesions (e.g. following strokes), fMRI visual field maps can reveal spared regions of cortex that may be missed if patient assessment relies on perimetry and anatomy of lesions alone. Even when perimetry results look stereotypical and can be categorised into hemianopia or quadrantanopia, the areas of spared cortex can be highly variable. FMRI field maps could serve as an important guide for selecting and optimising training and rehabilitation programmes for patients with damage to central visual pathway structures. Alongside a standardised battery of visual function tests, anatomical scans, and tractography data on connections between brain areas, this would provide a much richer clinical picture. Importantly, this approach may also offer useful information for a personalised approach to visual developmental disorders such as cerebral visual impairment (CVI). Here, we survey some recent results from the neuroimaging literature on measuring residual visual function, anatomy, and structural connectivity in stroke survivors, discuss recent results from rehabilitation approaches, and put forward a potential approach for characterising visual function using brain imaging in individuals with CVI.