Post-Acute COVID-19 Symptoms Clusters and Work Status.

Cerebral small and large vessel diseases are increasingly recognized as major contributors to cognitive impairment and dementia, either independently or in synergy with Alzheimer's disease (AD) pathology. Beyond overt stroke, chronic cerebral hypoperfusion and vascular dysfunction can drive insidious neurodegeneration, brain atrophy, and cognitive decline, constituting a central component of vascular contributions to cognitive impairment and dementia (VCID). Large artery stenosis (LAS), involving the extracranial or intracranial cerebral arteries, represents a prevalent yet underexplored vascular condition in this context. Even in the absence of clinically evident infarction, LAS can induce sustained hemodynamic compromise, endothelial dysfunction, and microvascular remodeling, which may accelerate brain tissue loss and impair cognitive function. However, sensitive and scalable biomarkers capable of capturing these subclinical neurodegenerative processes remain limited. The retina, as an embryological extension of the central nervous system, offers a unique and noninvasive window into cerebral microvascular and neurodegenerative changes. Advances in optical coherence tomography (OCT) and OCT angiography (OCTA) enable high-resolution, layer-specific quantification of retinal neuronal integrity and ocular microvascular architecture, including the superficial and deep retinal vascular plexuses and the choriocapillaris. Accumulating evidence suggests that retinal thinning and microvascular rarefaction are associated with brain atrophy, white matter injury, and cognitive impairment across aging, AD, and other neurodegenerative conditions. These findings have positioned ocular OCT/OCTA imaging as a promising source of biomarkers within emerging research frameworks for neurodegeneration and dementia. Nevertheless, several critical gaps remain. First, most prior studies have focused on patients with established neurodegenerative disease or overt cerebrovascular injury, limiting insights into earlier, potentially reversible stages of vascular-related neurodegeneration. The relevance of retinal and choroidal alterations to brain structure and cognition in noninfarcted LAS, a population characterized by chronic vascular insufficiency rather than acute tissue loss, has not been systematically examined. Second, while regional brain atrophy patterns are increasingly recognized as important for understanding dementia-related processes, the spatial specificity and symmetry of retina–brain associations in vascular disease contexts are poorly characterized. Machine learning (ML) approaches provide a complementary framework for integrating high-dimensional imaging and clinical data to improve prediction and risk stratification at the individual level. However, their value in noninfarcted LAS remains unclear.