The effective internalization of BT1, facilitated by the CD71 receptor, not only ensures the compound's delivery into retinal cells but also maintains the probe's photochemical properties and specificity towards pathological tau forms, with minimal cytotoxicity observed, underscoring its potential as a diagnostic tool for neurodegenerative diseases, particularly those associated with tauopathies like FTD. Here, MAPT is linked to neurodegenerative disease.