Abstract
Purpose :
Microvasculature plays an important role in Alzheimer’s disease (AD) pathology [ 1, 2]. As a protrusion from the brain, the retina might serve as a patient-friendly source of biomarkers for microvasculature. Previous research showed altered retinal vasculature parameters on fundus photography [3], choroidal thinning measured with EDI-OCT [4-8] and altered microvasculature on Optical Coherence Tomography Angiography (OCTa) [9, 10]. In this observational pilot we compared retinal microvasculature measured with OCTa in amyloid positive AD patients and controls.
Methods :
We included 11 early onset AD (EOAD) patients, 5 late onset AD (LOAD) patients and 25 controls from the Amsterdam Dementia Cohort (Mini-Mental State Examination (MMSE)≥17). All patients met NIA-AA criteria and were amyloid positive in cerebrospinal fluid (CSF) and/or on amyloid-PET. Controls were cognitively normal, amyloid negative subjects. All subjects underwent a complete neurological and ophthalmological examination including MRI and OCTa (Zeiss Cirrus AngioPlex). With OCTa we measured macular vessel density, perfusion and foveal avascular zone (FAZ). Patients with glaucoma were excluded.
Results :
LOAD patients had significantly lower macular vessel density and perfusion in the inner ring, compared to EOAD patients and controls (table 1). Macular vessel density, perfusion and avascular zone did not significantly differ between EOAD patients and controls. Age was not correlated with inner ring vessel density and perfusion in the cohort, when LOAD patients were excluded (n=36, linear regression B= -.-048, p=.283 and B=-.001 p=.412 respectively). OCTa measures did not correlate with MMSE or CSF amyloid or tau.
Conclusions :
Macular vessel density and perfusion in the inner ring measured with OCTa were lower in LOAD-patients compared to EOAD patients and controls, however age might be a confounding factor. Larger cohorts of patients are needed to assess the role of OCTa as a biomarker for vascular changes in AD, the role of age and differences between EOAD and LOAD.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.