Moreover, these studies encourage investigations on the clinical effects of NGF therapy for the treatment of neurodegenerative diseases characterized by an imbalance in NGF/TrkA signal transduction pathway in the eye and in the brain, including AMD and AD, respectively (Mufson et al., 2008; Aloe et al., 2015; Canu et al., 2017; Esposito et al., 2021). This evidence concerns the gene NTRK1 and Alzheimer disease.