Using OCT-A to explore biomarkers for neurodegenerative diseases

Amir H. Kashani, MD, PhD, a professor of ophthalmology at Johns Hopkins University, discussed a significant research publication in Alzheimers and Dementia that explored OCT-A angiography's potential in studying neurodegenerative diseases.

The study focused on developing a consensus method for analyzing retinal blood flow data across multiple international research sites. OCT-A (Optical Coherence Tomography Angiography) emerged as a groundbreaking non-invasive technique for measuring capillary-level blood flow in the eye. Unlike traditional methods such as MRI and PET scans, OCT-A could capture detailed images of blood flow without penetrating the skull. The research proposed that changes in retinal blood vessels could serve as a proxy for intracranial disease processes, particularly in conditions like Alzheimer disease and vascular cognitive impairment.

The research consortium brought together seven to eight universities that had collected thousands of OCT-A datasets. Their primary goal was to standardize data collection and analysis methods, addressing inconsistencies between different research groups' approaches. Key challenges included variations in scan sizes, vessel analysis, and data collection techniques. Artificial intelligence played a crucial role in the research. The team developed software to remotely assess image quality and efficiently review large datasets. This approach addressed the labor-intensive process of manually examining thousands of medical images, allowing researchers to quickly identify the most reliable scans for analysis.

The study revealed several important insights. Researchers discovered that data from both eyes might not always correlate perfectly, potentially due to biological variations or data collection methods. They also found that patients with conditions like diabetes and hypertension often showed reduced capillary density, which could indicate a predisposition to future cognitive issues. From a clinical perspective, the research positioned ophthalmology as a critical field for early risk stratification. OCT-A offered a quick, non-invasive screening method that could help identify individuals at high risk for cognitive decline. This approach could be particularly valuable for clinical trials and targeted medical interventions.

The ultimate goal was to develop a reliable method for detecting subtle changes in retinal blood flow that might predict future cognitive impairment. The conversation highlighted the potential of interdisciplinary research, combining ophthalmology, neurology, and advanced technologies like AI to unlock new understanding of neurodegenerative diseases and their early detection.