Support the North American Neuro-ophthalmology Society, McKnight Brain Institute, NIH Center Grant P30 EY014801, and a grant from Research to Prevent Blindness (RPB).
Ying Lin, Hong Jiang, Yi Liu, Yuqing Deng, Zhengyu Duan, Tatjana Rundek, Xiaoyan Sun, Bernard Baumel, Jianhua Wang; Interaction between retinal microcirculation and microstructure in patients with Alzheimer’s disease. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1124.
Purpose : The goal of this study was to determine the relationship between retinal blood flow velocity and ganglion cell layer thickness in patients with Alzheimer’s disease (AD).
Methods : Seventeen AD patients and 19 cognitively normal control subjects with 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 velocity of retinal arterioles and venules in the macular region. In addition, custom ultra-high resolution OCT (axial resolution ~ 3 µm) to thickness maps of 6 intraretinal layers (6 x 6 mm2). Automated segmentation software (Orion, Voxeleron LLC, Pleasanton, CA) was used to segment the thickness in the annulus (1- 6 mm in diameter) centered on the fovea. The segmented intraretinal layers were retinal nerve fiber layer (RNFL), ganglion cell–inner plexiform layer (GCIPL), inner nuclear layer (INL), outer nuclear layer (ONL), outer plexiform layer (OPL) and retinal photoreceptor (PR), in addition to the total retinal thickness (TRT).
Results : The total blood flow velocity in arterioles (3.20 ± 0.89 mm/s) and venules (2.50 ± 0.66 mm/s) were significantly lower in AD patients than in controls (arteriole: 3.98 ± 0.76 mm/, venule: 2.85 ± 0.54 mm/s, p < 0.05). Annular GCIPL thickness was 62.6 ± 5.2 µm in AD which was significantly lower than control (67.1 ± 6.5 µm, P < 0.05, Fig. 1), while no significant differences were found in other intra-retinal layers (P > 0.05). Blood flow velocities in arterioles and venules were positively related to GCIPL thickness in the annulus (arteriole, r = 0.54, venulue, r = 0.50, P < 0.05), while annular thicknesses of the other intra-retinal layers were not related to the velocity measurements (P > 0.05).
Conclusions : AD patients had neurodegeneration related to retinal blood flow velocity, which may indicate the interaction between retinal microcirculation and microstructure in AD pathogenesis.
Fig. 1. Relation between GCIPL thickness and retinal blood flow velocities. GCIPL thickness was measured using ultra-high resolution optical coherence tomography in 19 AD patients. The averaged thickness map of AD patients (A) was thinner than controls (B) in the annulus (1-6 mm in diameter). GCIPL thickness was related to blood flow velocities in arterioles (C) and venules (D).