Evaluation of ophthalmic biomarkers of dementia

Abstract

Purpose : Prior studies have found associations between retinal features and Alzheimer's disease. We evaluated retinal imaging data and measures of visual function to identify early biomarkers of dementia in individuals with varying levels of cognitive function.

Methods : Participants were recruited from the University of Washington Alzheimer’s Disease Research Center (UW ADRC) registry and assigned to control, mild cognitive impairment (MCI), or dementia cohorts. Measurements included photopic and mesopic visual acuity, contrast sensitivity, intraocular pressure (IOP), pupillometry, fundus photography, optical coherence tomography (OCT), OCT angiography, flavoprotein fluorescence (FPF) imaging, and two cognitive testing batteries - Tablet-based Cognitive Assessment Tool (TabCAT) and the NIH Toolbox. Linear regression models adjusted for age, sex, smoking history and education were used to assess mean differences between cohorts using the better seeing eye.

Results : As of October 5, 2022, 61 participants (mean age 72 [63-96], 50% female) completed the initial visit, including 38 controls, 9 with MCI, and 14 with dementia. Median age corrected NIH fluid composite scores were 105, 88, and 62. MCI and dementia participants scored lower on average by 12.5 and 27.1 points, respectively (p=0.071, p=0.029). Photopic visual acuity was highest in the control group and lower in the dementia cohort (difference in mean score=7.61, p=0.00051). Retinal nerve fiber layer (RNFL) and RNFL combined with ganglion cell/inner plexiform layer complex (GCL/IPL) thickness were lower in the dementia and MCI groups compared to the control group, however this was not statistically significant (Figure 1). The mean nerve disc FPF scores and macular FPF curve width were lower in the dementia group compared to the control group (p=0.046 and p=0.027, respectively)(Figure 2).

Conclusions : In this small, preliminary cross-sectional sample, we found promising differences in photopic visual acuity, FPF imaging, and various retinal thicknesses between people with and without dementia. These findings should be validated as more data is collected for this study and in future studies.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Retinal thickness measurements by cognitive group.

GCL/IPL, ganglion cell layer/inner plexiform layer; MCI, mild cognitive impairment; OCT, optical coherence tomography; RNFL, retinal nerve fiber layer.

 

Flavoprotein fluorescence (FPF) imaging measurements by cognitive group.
MCI, mild cognitive impairment.