• RNFL Thickness and Brain Neurodegeneration

    By Lynda Seminara
    Selected By: Deepak P. Edward, MD

    Journal Highlights

    JAMA Network Open
    2018;1(7):e184406

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    In a study of elderly patients without dementia, Méndez-Gómez et al. explored the relationship between thickness of the retinal nerve fiber layer (RNFL) and alterations in brain regions that are prone to neurodegen­eration. The authors found that greater RNFL thickness correlated with better findings during magnetic resonance imaging (MRI), not only in the brain’s visual pathways but also in areas linked to Alzheimer disease processes.

    For this investigation, the authors conducted a cross-sectional analysis of participants in the population-based Three-City Study in France. Brain volume was evaluated for 104 patients, and diffusion tensor imaging was analyzed for 79 patients. The mean age of the 104 participants was 80.8 years; 56.7% were women.

    Global RNFL was assessed by spectral-domain optical coherence tomography. T1-weighted MRI images were used for measurement of global white and gray matter fractions and the hippocampal fraction. Microstructural brain alterations were determined from diffusion tensor imaging at variouslocations, including the level of posterior thalamic radiations, limbic system tracts (the fornix and cingulum bundles), and the posterior limb of the internal capsule (control region). Linear regression models were applied, and adjustments were made for rele­vant confounders.

    Results of these assessments showed that a thicker global peripapillary RNFL was associated with better diffusion tensor imaging variables in the global and hippocampal part of the cingulum, a region of the brain associated with neurodegeneration noted in Alzheimer disease. No significant associations were found between the RNFL and the diffusion tensor imaging variables in the control region located outside the visual pathway, nor were any significant associations found with global MRI variables.

    Axonal thickness of the retina, which can be measured quickly and easily, may allow for early-stage detec­tion of neurodegeneration in the brain. The authors acknowledged that more research is needed to confirm the potential utility of RNFL thickness as an indicator of early degeneration of the brain in presymptomatic elderly adults.

    The original article can be found here.