Retinal imaging and tissue analysis for frontotemporal degeneration: recent advances and challenges for biomarker development.

Frontotemporal degeneration (FTD) is a group of neurodegenerative disorders affecting behaviour, language and executive functions. FTD is a common cause of early-onset dementia, but there are no FDA-approved treatments or established biomarkers for diagnosing and tracking these conditions, making early and accurate diagnosis challenging during life. Recent advances in retinal imaging, particularly through technologies like optical coherence tomography (OCT), have emerged as promising tools for identifying potential biomarkers for FTD and related neurodegenerative diseases. The retina, being an accessible extension of the central nervous system, has shown abnormalities that might serve as indicators of forms of FTD. Retinal imaging has revealed changes such as thinning of specific retinal layers that could correlate with molecular forms of FTD, Alzheimer's disease and other neurodegenerative diseases. These advances highlight the potential of retinal imaging to not only aid in diagnosis but also differentiate between various neurodegenerative conditions. Emerging data on retinal tissue analysis with immunohistochemistry and other techniques further support the potential of retinal biomarkers, though further studies are required to validate and refine these findings. Future advancements in retinal imaging technologies, along with longitudinal and autopsy-validated studies, are crucial for enhancing diagnostic capabilities and understanding FTD-related pathologies within the retina.