APOE and Schnyder corneal dystrophy: According to the proposed framework by SCD-I Working Group (Jessen et al. 2014), the SCD-plus criteria are (1) subjective decline in memory, rather than other domains of cognition; (2) onset of SCD within the last five years; (3) age at onset of SCD ≥ 60 years; (4) clinically suspected SCD; (5) feeling of worse performance than peers (here operationalized with the specific questions in the Cognitive Change Index (CCI) questionnaire); (6) confirmation of perceived cognitive decline by a close relative or friend; and (7) APOE ε4 alleles carriership.