The roles of ALDHs have been described as both beneficial and harmful.20 In our study, the AD study group exhibited upregulated expression of aldehyde dehydrogenases family 1 member A3 (AL1A3), which is reportedly expressed in cornea, and may have important roles in the protection of epithelial cells against OS.21 AL1A3 has also been described as having chaperone-like activities against protein aggregation in epithelial cells.22,23 In AD, aggregating proteins Aß peptide and tau are detected in the eyes,24 indicating the importance of chaperone-like activities in AD. This evidence concerns the gene MAPT and Alzheimer disease.