We focused on the GCIPL, as phosphorylated alpha-synuclein has been found in the IPL at postmortem,7 and this layer has been most consistently linked with changes in PD.9 12 22 Given the widespread white matter changes seen with visuoperceptual deficits in PD, we hypothesised that patients with higher order visual changes would show greater conversion to dementia and poor outcomes over time. Here, SNCA is linked to Parkinson disease.