Chalk up another victory for OCT as a screening tool for Alzheimer’s disease (AD) patients. Researchers have found that OCT angiography (OCT-A) could be a noninvasive method to analyze early retinal architecture and vascular changes in individuals with preclinical AD.

A recent study compared a group of 14 participants who had biomarkers positive for AD and a diagnosis of preclinical AD with another group of 16 participants without biomarkers that served as a control group. Neuropsychometric testing results determined that all participants were cognitively normal. From analyzing 58 eyes, the foveal avascular zone (FAZ) was increased and the inner foveal thickness was decreased in the biomarker-positive group.

Researchers believe that their findings suggest individuals with biomarker-positive, preclinical AD might have retinal vascular and architectural alterations that are apparent before the onset of clinically detectable cognitive symptoms. The researchers also suggest that the retina undergoes neuronal loss and vascular modifications far earlier in the disease progression than previously thought.

Researchers also acknowledge that multiple other potential causes for an enlarged FAZ exist and that further assessment of OCT-A in the general population is necessary. They note that longitudinal studies in larger cohorts are needed to determine whether this finding has value in identifying preclinical AD.

Nevertheless the study’s data suggest that OCT-A has the potential for rapid, noninvasive and cost-effective identification of individuals who are likely to have preclinical AD.   

O’Bryhim BE, Apte RS, Kung N, et al. Association of preclinical Alzheimer disease with optical coherence tomographic angiography findings. JAMA Ophthalmol. August 23, 2018. [Epub ahead of print].