Sarah Hamm-Alvarez, PhD: Could Tears Hold a Parkinson Biomarker?

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It’s difficult to diagnose Parkinson disease before some permanent neurological damage occurs. But tears may hold the key to earlier diagnoses.

One of the challenges neurologists face in treating patients with Parkinson disease is that early diagnosis is difficult. By the time most patients are able to be diagnosed, there is already permanent neurological damage.

This led a team of ophthalmologists and neurologists at the Keck School of Medicine of USC to begin research to identify a biomarker in tears to allow for earlier identification of Parkinson disease.

Sarah Hamm-Alvarez, PhD, Professor of Ophthalmology at the USC Roski Eye Institute at the Keck School of Medicine of USC, spoke with MD Magazine® about this biomarker research, which she presented at the 2019 Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO) in Vancouver, BC.

“A few years ago, we became interested in the possibility that the lacrimal gland, which secretes tears and tear proteins, might be responsive to some of the same neural pathways that are affected in early Parkinson's disease,” Hamm-Alvarez told MD Mag.

What research have you presented here at ARVO?

Why look at tears for a Parkinson biomarker?

So, the research involves our attempt to identify a potential diagnostic biomarker or biomarkers—plural—in the tears. And the reason that we're interested in doing this, and doing this in particular for Parkinson's disease, is that it's very difficult to diagnose Parkinson's disease before the characteristic symptoms of motor dysfunction appear.A few years ago, we became interested in the possibility that the lacrimal gland, which secretes tears and tear proteins, might be responsive to some of the same neural pathways that are affected in early Parkinson's disease and that changes in the stimulation of that gland might lead to characteristic changes in proteins or protein profiles in the tears that could potentially serve as an early diagnostic for Parkinson's disease. One of the things that we did then was to try to start investigating whether or not these changes in the tear composition of Parkinson's disease patients occurred.