Evidence Growing That Eyes May Be A Window to Alzheimer’s Diagnosis
Results presented at the 122ndAnnual Meeting of the American Academy of Ophthalmology suggest that optical coherence tomography (OCT) and OCT-angiography (OCTA) may be diagnostic for patients with presymptomatic Alzheimer’s disease (AD). Patients with AD had significantly smaller macular blood vessel density (VD) and perfusion density (PD) measures compared to patients with mild or no cognitive impairment. In another study, associations between macular thickness, memory performance, and hippocampal volume were shown in in asymptomatic patients with a family history of AD.
In a cross-sectional study (NCT03233646), patients were diagnosed by neurologists, using National Institute on Aging-Alzheimer’s Association (NIAAA) criteria, with AD (n = 39), mild cognitive impairment (MCI) or no cognitive impairments. All subjects had OCTA; 22.2%, 8.9%, and 5.6% of patients with AD, MCI, and no cognitive impairment, respectively were excluded from the results due to poor scan quality.
Patients with AD had decreased VD (P = .015) and PD (P = .009) over a 3 mm-circle and decreased VD (P = .008) and PD (P = .004) over a 3-mm ring compared to control subjects.
As noted in the poster presentation, “These findings support previous studies using fundus photography that showed patients with AD had narrower venular caliber, decreased arteriolar and venular fractal dimensions, and increased arteriolar and venular tortuosity.”
In the study of patients with (n = 138) and without a family history of AD (n = 57), matched for age, were evaluated with OCT, brain MRI, and cognitive assessment (executive function and episodic memory domains). Patients with a family history of AD had thinner macular retina layers, and in these patients, thicker macular inner layers were associated with better performance on measures of executive function and with higher left hippocampal volume on brain MRI.