Researchers have yet again proven Alzheimer’s can be diagnosed before symptoms are even present—using optical coherence tomography angiography (OCT-A). The Duke University team used OCT-A to evaluate 70 eyes from 39 Alzheimer’s patients, 72 eyes from 37 participants with mild cognitive impairment (MCI) and 254 eyes from 133 controls. Participants also underwent cognitive evaluation with a mini-mental state examination.1

After comparing the retinal microvasculature in each group, they found that Alzheimer’s patients had significantly reduced macular vessel density, perfusion density and ganglion cell-inner plexiform layer (GC-IPL) thickness compared with MCI participants and controls. There was no difference in superficial capillary plexus vessel density or perfusion density between MCI participants and controls. Other parameters such as foveal avascular zone area and central subfield thickness did not differ significantly between groups.1

Alzheimer’s patients showed significantly decreased GC-IPL thickness over the inferior and inferonasal sectors compared with MCI participants and significantly decreased GC-IPL thickness over the entire superonasal, inferior and inferonasal sectors compared with controls.1

The researchers note that changes in the retinal microvasculature may mirror small vessel cerebrovascular changes in Alzheimer’s, helping eye doctors detect the disease earlier.1

“Ultimately, the goal would be to use this technology to detect Alzheimer’s early, before symptoms of memory loss are evident, and be able to monitor these changes over time in participants of clinical trials studying new Alzheimer’s treatments,” Sharon Fekrat, MD, study author, said in a press release.2 

1. Yoon SP, Grewal DS, Thompson AC, et al. Retinal microvascular and neurodegenerative changes in Alzheimer’s disease and mild cognitive impairment compared with control participants. Opthalmology. March 11, 2019. [Epub ahead of print].

2. Could An Eye Doctor Diagnose Alzheimer’s Before You Have Symptoms? Duke Health. March 11, 2019. Accessed March 18, 2019.