Relationship of Area of Soft Drusen in Retina with Cerebral Amyloid-β Accumulation and Blood Amyloid-β Level in the Elderly

<jats:sec><jats:title>Background:</jats:title><jats:p> Histopathological studies have confirmed that soft drusen contains amyloid-β (Aβ). </jats:p></jats:sec><jats:sec><jats:title>Objective:</jats:title><jats:p> To examine the relationship between the area of soft drusen in the macular area and cerebral Aβ accumulation or plasma Aβ level in elderly persons without dementia. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> Fourteen consecutive patients (18 eyes) aged ≥50 years with macular soft drusen were studied prospectively. From color fundus photographs, the area of soft drusen (pixel) within a 6,000 μm diameter with the macula as center was measured. Standard uptake value ratio (SUVR) was obtained from positron emission tomography using florbetapir, which indicates the ratio of cerebral cortical-to-cerebellar Aβ accumulation. Ratio of plasma Aβ<jats:sub>1-42</jats:sub> to Aβ<jats:sub>1-40</jats:sub> level was calculated. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> Mean age was 73.3±7.6 years. The soft drusen area was 4.32±2.42 mm<jats:sup>2</jats:sup>. The SUVR was 1.08±0.15. Plasma Aβ<jats:sub>1-42</jats:sub>/Aβ<jats:sub>1-40</jats:sub> ratio was 0.17±0.08. When SUVR ≥1.10 was defined as positive and <1.10 as negative, the soft drusen area in SUVR-positive patients (6.19±1.14 mm<jats:sup>2</jats:sup>) was significantly ( p = 0.0043) larger than that in SUVR-negative patients (3.13±2.27 mm<jats:sup>2</jats:sup>). Multivariate regression analysis showed that SUVR positivity correlated with soft drusen area ( p = 0.0484) and with Voxel-based Specific Regional Analysis System for Alzheimer’s Disease score ( p = 0.0360). However, there was no correlation with gender ( p = 0.1921), age ( p = 0.2361), Alzheimer’s Disease Assessment Scale score ( p = 0.6310), Mini-Mental State Examination score ( p = 0.4246), or plasma Aβ<jats:sub>1-42</jats:sub>/Aβ<jats:sub>1-40</jats:sub> ratio ( p = 0.8398). </jats:p></jats:sec><jats:sec><jats:title>Conclusion:</jats:title><jats:p> Among elderly persons without dementia, the area of soft drusen was larger in those with more extensive cerebral Aβ accumulation. The area of soft drusen may be a biomarker of cerebral Aβ accumulation. </jats:p></jats:sec>