Stimulus-driven cerebrospinal fluid dynamics is impaired in glaucoma patients

Cerebrospinal fluid (CSF), partly driven by sensory stimulation, is crucial for maintaining homeostasis and clearing metabolic waste. Whether such stimulus-driven CSF flow is disrupted in age-related neurodegenerative diseases of the visual system remains unclear. This study examined the CSF flow during visual stimulation in glaucoma patients and healthy older adults using functional magnetic resonance imaging. In glaucoma, CSF inflow becomes progressively decoupled from the visually evoked blood-oxygenation-level-dependent (BOLD) response. Specifically, the characteristic stimulus-locked CSF patterns, which decrease after stimulus onset and increase after offset, diminish with disease severity. Mediation analysis suggests this flattened CSF pattern is driven by a flatter ascending BOLD slope, leading to a shallower CSF trough and a reduced post-stimulus surge. These results indicate that glaucoma-related functional impairments contribute to downstream alterations in CSF dynamics. Overall, this study provides insight into how glaucoma disrupts visually driven CSF inflow and highlights in vivo biomarkers for monitoring CSF dynamics.