Retinal hypoperfusion in patients with Alzheimer’s disease

Abstract

Purpose : The goal of this study was to determine the retinal blood flow of pre-capillary arterioles and post-capillary venules in patients with Alzheimer’s disease (AD).

Methods : Seventeen AD patients and 16 cognitively normal control subjects within a similar age range were recruited. A retinal function imager (RFI, Optical Imaging Ltd, Rehovot, Israel) was used to image an area of 4.3 x 4.3 mm² centered on the fovea to measure the blood flow volume of retinal arterioles and venules in the macular region. The blood flow volume was calculated within a 2.3-mm circle centered on the fovea. The diameter of the vessels which crossed the circle was determined by counting the pixels of the full width and half of the maximum in the intensity profile, which was perpendicular to the vessel. The width in the pixel was then converted to micrometers. Using measured velocities and corresponding vessel diameters, the blood flow volume of each vessel crossing the circle was calculated. The total perifoveal flow volume (arteriole and venule, separately) in the circled perifoveal zone was the sum of all measured blood flow in the circle (Fig. 1).

Results : The total perifoveal blood flow volumes in arterioles (2.64 ± 0.72 nL/s) and venules (2.39 ± 0.63 nL/s) were significantly lower in AD patients than in controls (arteriole: 4.10 ± 0.36 nL/s, p <0.01; venule: 3.96 ± 0.42 nL/s, p < 0.01). Neither arteriolar nor venular blood flow volume was related to age and mini mental state examination (MMSE) score (P > 0.05).

Conclusions : AD patients had retinal hypoperfusion indicated by lower retinal blood flow volume, which may suggest that vasculopathies may play a role in pathomechanism of AD.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.