Retinal scans show thinner layers in frontotemporal dementia than Alzheimer disease

Frontotemporal dementia is a rare form of Alzheimer disease that changes personality and behavior before memory fades. Doctors need better ways to tell these conditions apart early on. A recent study looked at retinal scans to see if they could help. The researchers examined eye layers in 139 people with frontotemporal dementia and compared them to others with Alzheimer disease or mild cognitive impairment. They also included healthy controls in the comparison group. The total group had 29 people with mild cognitive impairment and 14 with TDP-43 proteinopathy. Five people had tauopathy. The team measured retinal nerve fiber layer thickness and ganglion cell layer-inner plexiform layer thickness using optical coherence tomography. This technology uses light to take detailed pictures of the eye. The results showed that the retinal nerve fiber layer was significantly thinner in individuals with frontotemporal dementia compared with Alzheimer disease. The ganglion cell layer-inner plexiform layer was also significantly thinner in those with frontotemporal dementia compared with controls. When the team pooled data across multiple retinal biomarkers, the differences were not significant. The study did not report any safety issues because no medications were tested. The authors noted that larger longitudinal studies with standardized protocols are needed to determine the diagnostic and prognostic utility of retinal biomarkers in frontotemporal dementia.