Trans‐Synaptic Retrograde Retinal Degeneration After Post‐Chiasmatic Stroke: A Systematic Review of Empirical Evidence

BACKGROUND: Retrograde trans-synaptic degeneration (RTSD) refers to the progressive loss of retinal cells following damage to the post-geniculate visual pathway. The advent of optical coherence tomography (OCT) has allowed the measurement and quantification of retinal layers, in turn providing compelling evidence of RTSD in stroke patients and highlighting that assessing the temporal and functional evolution of RTSD has important clinical implications. METHODS: We conducted a systematic review up until 7th July 2025 to summarize the OCT evidence on post-stroke RTSD. Eligible articles on this topic were searched in PubMed, Web of Science, and Scopus databases. Twenty-eight papers, involving 888 patients and 624 healthy controls, were included, and their results were systematically described and qualitatively analyzed. RESULTS: Overall, literature shows that RTSD is a frequent outcome of post-chiasmatic strokes. RTSD is operationalized by measuring the thickness of the peripapillary retinal nerve fiber and macular layers. The latter appears to be a more robust structural biomarker, showing more consistent findings across studies, with its magnitude better correlating with patients' visual field defects. RTSD starts early after the stroke's onset and progresses for several years, with severity depending on lesion location and extension. Future investigations are needed to draw more robust conclusions on RTSD temporal dynamics, clarifying the relation between structural and functional loss. CONCLUSIONS: Current literature highlights the need to consider the RTSD among the primary outcomes of post-chiasmatic stroke, given its implications on clinical management and neurorehabilitation, making the longitudinal assessment of this degenerative process crucial for prevention.