BACKGROUND: Alzheimer's disease (AD) and frontotemporal dementia (FTD) are leading causes of cognitive decline. Optical coherence tomography (OCT) allows the measurement of thickness of retinal neuroaxonal layers. While in AD and mild cognitive impairment (MCI), retinal nerve fiber layer (RNFL) thinning is frequently reported, less information is available on ganglion cell layer-inner plexiform layer (GCL-IPL). Data on FTD are lacking.

OBJECTIVE: To obtain cross-sectional information on RNFL and GCL-IPL thickness among MCI, AD, FTD, and healthy controls (HC), and their correlations with dementia severity.

METHODS: Peripapillary OCT scans were obtained in 27 MCI, 39 AD, 17 FTD, 49 HC using high-definition Heidelberg Spectral-domain OCT, with RNFL and GCL-IPL thickness measurement. Statistical analysis tested group effects and correlation with gender, disease duration and severity (Mini-Mental State Examination, MMSE).

RESULTS: RNFL showed a significant group effect [F(4,132) = 3.786, p = 0.006], being reduced versus controls in MCI (p = 0.033), moderate AD (p = 0.025), and FTD (p 

CONCLUSION: Retinal neuroaxonal thinning occurs in MCI/AD consistently with previous reports, as well as in FTD. Correlation with disease severity in AD suggests that retinal and brain neurodegeneration may occur in parallel to some extent, and prompts larger studies aimed at providing surrogate endpoints for clinical trials in AD.