Exploring the ocular glymphatic system: The association of MRI-visible perivascular spaces with intraocular pressure and tear total-tau

Motivation: Preclinical research suggests an ocular glymphatic system similar to the cerebral system, driven by intraocular pressure (IOP). However, human studies are scarce. Goal(s): To explore the eye-brain connection by investigating tear total-tau as a potential early marker of cerebral glymphatics and consider the link between IOP (driver of ocular glymphatics) and impaired cerebral waste clearance. Approach: MRI-visible PVS were scored on 7T images and related to IOP and tear total-tau. Results: Higher tear total-tau and lower IOP were associated with more PVS, implying a connection to impaired cerebral waste clearance and aligning with the potential presence of a human ocular glymphatic system. Impact: Our exploratory results suggest that higher tear-tau and a reduced driving force of ocular waste clearance are connected to impaired cerebral waste clearance. Thereby, this study bridges the gap between the potential human ocular glymphatic system and cerebral waste clearance.