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Using Optical Coherence Tomography and Optokinetic Response As Structural and Functional Visual System Readouts in Mice and Rats
Published on: January 10, 2019
Optical coherence tomography identifies outer retina thinning in frontotemporal degeneration
Benjamin J Kim1, David J Irwin2, Delu Song2
1From the Scheie Eye Institute, Department of Ophthalmology (B.J.K., D.S., E.D., J.D.L., A.R.R., W.P., G.-S.Y., T.S.A., J.L.D.), and Frontotemporal Lobar Degeneration Center, Department of Neurology (D.J.I., M.G.), Perelman School of Medicine, University of Pennsylvania, Philadelphia. benjamin.kim@uphs.upenn.edu.
Objective:
Whereas Alzheimer disease (AD) is associated with inner retina thinning visualized by spectral-domain optical coherence tomography (SD-OCT), we sought to determine if the retina has a distinguishing biomarker for frontotemporal degeneration (FTD).
Methods:
Using a cross-sectional design, we examined retinal structure in 38 consecutively enrolled patients with FTD and 44 controls using a standard SD-OCT protocol. Retinal layers were segmented with the Iowa Reference Algorithm. Subgroups of highly predictive molecular pathology (tauopathy, TAR DNA-binding protein 43, unknown) were determined by clinical criteria, genetic markers, and a CSF biomarker (total tau: β-amyloid) to exclude presumed AD. We excluded eyes with poor image quality or confounding diseases. SD-OCT measures of patients (n = 46 eyes) and controls (n = 69 eyes) were compared using a generalized linear model accounting for intereye correlation, and correlations between retinal layer thicknesses and Mini-Mental State Examination (MMSE) were evaluated.
Results:
Adjusting for age, sex, and race, patients with FTD had a thinner outer retina than controls (132 vs 142 μm, p = 0.004). Patients with FTD also had a thinner outer nuclear layer (ONL) (88.5 vs 97.9 μm, p = 0.003) and ellipsoid zone (EZ) (14.5 vs 15.1 μm, p = 0.009) than controls, but had similar thicknesses for inner retinal layers. The outer retina thickness of patients correlated with MMSE (Spearman r = 0.44, p = 0.03). The highly predictive tauopathy subgroup (n = 31 eyes) also had a thinner ONL (88.7 vs 97.4 μm, p = 0.01) and EZ (14.4 vs 15.1 μm, p = 0.01) than controls.
Conclusions:
FTD is associated with outer retina thinning, and this thinning correlates with disease severity.

