Following the Status of Visual Cortex Over Time in Patients With Macular Degeneration Reveals Atrophy of Visually Deprived Brain Regions

Previous research has shown atrophy of visual cortex can occur in retinotopic representations of retinal lesions resulting from eye disease. However, the time course of atrophy cannot be established from these cross-sectional studies, which included patients with longstanding disease of varying severity. Our aim, therefore, was to measure visual cortical structure over time in participants after onset of unilateral visual loss resulting from AMD. Inclusion criteria were onset of acute unilateral neovascular AMD with bilateral dry AMD based on clinical examination. Therefore, substantial loss of unilateral visual input to cortex was relatively well-defined in time. Changes in cortical anatomy were assessed in the occipital lobe as a whole, and in cortical representations of the lesion and intact retina, the lesion and intact projection zones, respectively. Whole brain, T1-weighted magnetic resonance imaging was taken at diagnosis (before antiangiogenic treatment to stabilize the retina), during the 3- to 4-month initial treatment period, with a long-term follow-up approximately 5 (range 3.8-6.1 years) years later. Significant cortical atrophy was detected at long-term follow-up only, with a reduction in mean cortical volume across the whole occipital lobe. Importantly, this reduction was explained by cortical thinning of the lesion projection zone, which suggests additional changes to those associated with normal aging. Over the period of study, antiangiogenic treatment stabilized visual acuity and central retinal thickness, suggesting that the atrophy detected was most likely governed by long-term decreased visual input. Our results indicate that consequences of eye disease on visual cortex are atrophic and retinotopic. Our work also raises the potential to follow the status of visual cortex in individuals over time to inform on how best to treat patients, particularly with restorative techniques.