Olivares Ordoñez Marco Antonio, Smith Rebekah Cossette, Yiu Glenn, Liu Yin Allison
School of Medicine, University of California, Davis, Sacramento, CA.
Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, CA.
Int Ophthalmol Clin. 2025 Jan 1;65(1):59-67. doi: 10.1097/IIO.0000000000000549. Epub 2024 Dec 23.
"The eyes are a window to the brain," prompting the investigation of whether retinal biomarkers can indicate Alzheimer disease (AD) and cognitive impairment. AD is a neurodegenerative condition with a lengthy preclinical phase where pathologic changes in the central nervous system (CNS) occur before clinical symptoms. Mild cognitive impairment (MCI) often precedes AD. As part of the CNS, the retina exhibits similar pathologic changes related to AD as those seen in the brains of patients with MCI. Noninvasive imaging technologies such as optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) allow high-resolution visualization of the retina, providing an opportunity to screen and monitor AD noninvasively. In this review, we summarize the relationship between AD and retinal pathology detected by OCT and OCTA. The most common findings in patients with AD include peripapillary retinal nerve fiber layer thinning, decreased macular thickness, an enlarged foveal avascular zone, and decreased vascular densities in the superficial and deep capillary plexuses. These retinal changes correlate with magnetic resonance imaging (MRI) findings of cerebral atrophy, positron emission tomography (PET) findings of increased amyloid load, and neuropsychological testing results suggesting cognitive dysfunction. We conclude that retinal microstructural and microvascular abnormalities may serve as biomarkers for the early detection and clinical monitoring of AD and as tools for evaluating potential treatment effects. Future studies should focus on standardizing protocols for in vivo ophthalmic imaging to measure retinal pathology in AD and MCI.
“眼睛是大脑的一扇窗户”，这促使人们研究视网膜生物标志物是否能够指示阿尔茨海默病（AD）和认知障碍。AD是一种神经退行性疾病，具有漫长的临床前期，在此期间中枢神经系统（CNS）会出现病理变化，之后才会出现临床症状。轻度认知障碍（MCI）通常先于AD出现。作为CNS的一部分，视网膜呈现出与MCI患者大脑中所见相似的、与AD相关的病理变化。光学相干断层扫描（OCT）和光学相干断层扫描血管造影（OCTA）等非侵入性成像技术能够实现视网膜的高分辨率可视化，为非侵入性筛查和监测AD提供了契机。在本综述中，我们总结了AD与通过OCT和OCTA检测到的视网膜病理之间的关系。AD患者最常见的表现包括视乳头周围视网膜神经纤维层变薄、黄斑厚度降低、中心凹无血管区扩大以及浅表和深部毛细血管丛的血管密度降低。这些视网膜变化与脑萎缩的磁共振成像（MRI）结果、淀粉样蛋白负荷增加的正电子发射断层扫描（PET）结果以及提示认知功能障碍的神经心理学测试结果相关。我们得出结论，视网膜微观结构和微血管异常可能作为AD早期检测和临床监测的生物标志物，以及评估潜在治疗效果的工具。未来的研究应专注于标准化用于体内眼科成像的方案，以测量AD和MCI患者的视网膜病理。
