Alzheimer’s disease affects 5.3 million people in the US, and is the leading cause of elderly dementia in the world. Researchers everywhere are working constantly to understand the disease better and develop new treatment and testing modalities that will benefit these patients.

Now a team of researchers from the University of California in Irvine have made what may prove to be a significant discovery about the progression of Alzheimer’s disease, all thanks to looking into the eyes of mice.

The team, led by UCI neuroscientist Zhiqun Tan, found that the retinas of lab mice that had been genetically engineered to have Alzheimer’s disease underwent similar changes as appear in the brain. The most significant finding was that amyloid plaque lesions accumulated in both sites.

Tan and his team also found that when testing various Alzheimer’s treatments on the altered mice retinal changes occurred that may indeed better predict how the treatments would work in humans than studying the creature’s brains.

These results mean that the development of retinal imaging tests that could diagnose Alzheimer’s disease may be possible in the near future. Such testing would be cheaper and less invasive than the brain imaging techniques that are currently in widespread diagnostic use.

During the course of the study the UCI team analyzed the retinas of lab mice that had also been treated with immunotherapy. The vaccinated mice appeared to score higher on learning and memory tests than their untreated brethren, and their brains contained fewer plaque lesions. Looking into their eyes the researcher observed that retinas displayed a similar result, fewer plaque lesions in the eyes of the immunized mice. It was also noted that the retinas were more inflamed and subject to vascular changes than the brain.

When immunotherapy was tested in human Alzheimer’s patient’s brain tissue inflammation was observed in a similar pattern as had been observed in the mice retina. This, says Tan, indicates that the retina may be more sensitive when it comes to reflecting changes occurring in the brain.

Tan is excited by his team’s discoveries saying “”Brain tissue isn’t transparent, but retinas are. I hope in the future we’ll be able to diagnose the disease and track its progress by looking into the eyes.” To that end, other UCI researchers, including Dr. Steven Schreiber, neurology professor and interim chair of the department are already working to develop retinal imaging technology for use in human subjects.

The study will be published in the November issue of the American Journal of Pathology.