MAPT and Alzheimer disease: For example, the majority of the studies on retinal vascular changes in AD are cross‐sectional studies including individuals with AD dementia, while others have investigated cohorts with MCI,170, 198 both AD and MCI,111, 187, 191, 199, 201, 203, 204, 223, 224, 230 neocortical Aβ or hyperphosphorylated tau positive,120, 131, 200, 205, 226, 236APOE ε4 gene carrier,198, 226 and cognitively impaired189, 225, 229 individuals as subjects.