We did not detail: 1) findings in subgroups stratified by key characteristics (e.g. age, sex, ethnicity, or apolipoprotein E status); 2) how differences in the classification of mild cognitive impairment or dementia between studies may have affected the results; and 3) exclusion criteria used in different studies (e.g. in some, but not all, studies individuals with eye diseases such as glaucoma and diabetic retinopathy were excluded). Here, APOE is linked to diabetic retinopathy.