The simple, noninvasive test involves examining retinas, the light-sensitive tissue that coats the back of eyes, through a camera. (WESTEND61/GETTY STOCK IMAGES)

Alzheimer's disease, the debilitating neurological disorder, is evidently more than meets the eye.

Researchers at the University of Minnesota used technology to discover early signs of the condition in the retinas of mice, and they're hopeful the same could be found in humans.

The University of Minnesota Center for Drug Design study was published in June in the journal Investigative Ophthalmology and Visual Science.

The simple, noninvasive test involves examining retinas, the light-sensitive tissue that coats the back of eyes, through a camera. The retina and brain undergo similar changes due to Alzheimer's, but the retina is much easier to see since it's more accessible.

Indeed, researchers detected patterns in the retinas – through changes in light reflection as early stages of amyloid plaque gathered – that signified the disease's progression. Amyloid plaque is a key marker for Alzheimer's disease. Alzheimer's disease can currently only be identified after it's already formed, Dr. Robert Vince, director of the Center for Drug Design, said in a post on the University of Minnesota's website.

There's no definitive test for Alzheimer's – it's diagnosed based on symptoms – so the ability to see progression of the disease before symptoms appear could help experts test new preventive and treatment drugs.

The eye test will enter human trials this month, and it will be tested in both patients with and without Alzheimer's disease.

As many as 5.1 million Americans could be suffering from Alzheimer's disease, according to the Alzheimer's Foundation of America. Warning signs include memory problems, word-finding difficulty, vision and spatial issues and off reasoning or judgment, according to the National Institute on Aging.