Retinal nerve fiber layer thickness predicts CSF amyloid/tau before cognitive decline

Area of Science:

• Ophthalmology
• Neurology
• Biomarker Discovery

Background:

• Alzheimer's disease (AD) pathology begins years before clinical symptoms manifest.
• Early detection of AD pathology is crucial for timely intervention and management.
• Retinal nerve fiber layer (RNFL) thinning is a known indicator of established AD.

Purpose of the Study:

• To investigate if RNFL thickness can predict underlying Alzheimer's disease (AD) pathology in cognitively healthy (CH) individuals.
• To determine the efficacy of optical coherence tomography (OCT) in identifying individuals with pathological cerebrospinal fluid (CSF) biomarkers for AD.
• To assess the potential of RNFL thickness as a non-invasive screening tool for preclinical AD.

Main Methods:

• Cognitively healthy individuals were classified into normal (CH-NAT) or pathological (CH-PAT) subgroups based on CSF Aß42/tau ratios.
• Spectral-domain optical coherence tomography (OCT) was used to measure RNFL, ganglion cell-inner plexiform layer (GC-IPL), and macular thickness.
• Logistic regression models were employed for classification and group difference analysis.

Main Results:

• The CH-PAT group exhibited significantly thinner RNFL compared to the CH-NAT group (p < 0.001).
• RNFL thickness achieved 87% sensitivity and 56.3% specificity in classifying CH individuals with or without AD pathology.
• No significant age differences were observed between the CH-PAT and CH-NAT groups.

Conclusions:

• Retinal nerve fiber layer (RNFL) thickness measurements can predict the presence of cerebrospinal fluid (CSF) biomarkers for Alzheimer's disease (AD) pathology in cognitively healthy individuals.
• Optical coherence tomography (OCT) offers a sensitive and objective method for screening early AD pathology.
• Further research into OCT technology is warranted for monitoring and screening individuals at risk for AD.