It’s hard to overstate how devastating neurodegenerative diseases like Alzheimer’s can be. But while there is no cure for Alzheimer’s yet, early diagnosis that results in earlier treatment can help to delay its progression. Today, a doctor diagnosing Alzheimer’s would likely do so through a combination of memory tests, blood tests (to rule out other reasons for memory being affected), and a CT scan. However, in the future it could conceivably be as simple as carrying out a relatively basic eye test. This may speed up diagnosis since it could show positive results before the onset of symptoms.

“[In our new work] we found evidence of neurofilament light chain (NfL) in eye fluid,” Manju Subramanian, an ophthalmologic surgeon at Boston Medical Center, told Digital Trends. “Increased levels of NfL are detectable in blood and cerebrospinal fluid in conditions such as Alzheimer’s and Parkinson’s Disease.”

Subramanian noted that it is too early to confirm if the eye could indeed be a source of diagnosis, although she described this as a “foundational” study for such work to be explored later on. The Boston Medical Center study is the first time that NfL, which is biomarker for diagnosis of certain neurodegenerative diseases, has been found in the eye.

“The eye is an extension of the brain, and as an optical system, the eye can provide a direct window to visualize disease,” she said. “Many diseases that affect the central nervous system can also affect the eye. As such, direct sampling of ocular fluid for quantification of biomarkers may provide a uniquely accessible and cost-effective means for diagnosis.”

The researchers in the study collected eye fluid samples from 77 patients undergoing eye surgery at Boston Medical Center. All 77 patients tested positive for the presence of NfL.

Neurodegenerative diseases are currently on the rise around the world as many people are living longer than before. Alzheimer’s remains the most common disease in this category, affecting around 5.5 million Americans today. Parkinson’s is less common, but still affects over one million people in the United States. It’s too early to jump to conclusions about how this work could potentially impact these numbers. However, every piece of research in this area represents a step in the right direction. This is definitely research to follow.

A paper describing the work was recently published in the journal Alzheimer’s Research & Therapy.