Palo Alto, CA —Your eyes could reveal far more about your health than you might expect. In the Star Protocols article, “Protocol to extract tear fluid for proteomics using Schirmer strips,” researchers at Stanford University present a new method they call “TEARDROP” that can identify thousands of proteins in human tears.
Because tear fluid carries proteins linked not only to eye conditions but also to systemic diseases like diabetes and autoimmune disorders, this breakthrough could help doctors detect health problems earlier and more accurately.
Vinit Mahajan M.D., Ph.D., Stanford professor and department of ophthalmology vice chair of research, said, “My team is excited to share our method with other scientists because of its potential impact on health care. This innovation turns something as ordinary as tears into a window into the body’s broader health—suggesting that future routine eye exams could help flag disease early, guide treatment decisions, and personalize patient care.”
The process begins with Schirmer strips—soft paper strips commonly used by eye doctors to measure tear production. In this protocol, the strips are gently placed at the outer corner of the lower eyelid, where they naturally absorb tears. The strip is frozen and sent to the lab for processing.
The researchers describe TEARDROP (Tear Enrichment using Advanced Recovery via Deep Resolution of Proteins) as a careful series of biochemical steps to extract and retrieve tear proteins. Specialized nanoparticles capture proteins in a solution that undergoes liquid chromatography and mass spectrometry.
Antione Dufour Ph.D., a visiting professor from the University of Calgary who collaborated with the Mahajan lab to develop TEARDROP, said, “The results were astonishing. In the past, we could reliably measure only a few hundred proteins in human tears. With TEARDROP, we were picking up over 5000 proteins. This changes everything. The depth of data can provide deep insight into the molecular events driving disease.”
Because tear proteins can change when the body is under stress or fighting disease, analyzing them may help doctors detect health issues earlier and more accurately. Tear proteomics could help monitor chronic diseases more gently than blood draws, provide insight for personalized treatments, and even reduce the need for more expensive or invasive diagnostic procedures.
Prithvi Mruthyunjaya M.D., MHS, Stanford professor of ophthalmology and director of ocular oncology said, “What makes our Stanford protocol especially notable is the potential impact for eye cancer. Because collecting tears is noninvasive, this “liquid biopsy” could be used to screen and diagnose cancers that occur on the surface of the eye, like conjunctival melanoma or squamous cell neoplasia. We are now testing this hypothesis.”
Mahajan noted, “Over time, TEARDROP could shift parts of diagnostic medicine toward earlier detection, lower cost, and broader reach.”
The paper authors include Ngo GH, Chadha M, Sun YJ, Yu G, Lee SH, Yeh TC, Almeida DRP, Bassuk AG, Mruthyunjaya P, Dufour A, and Mahajan VB. It is published in STAR Protocols, 2025 Oct 16;6(4):104146. doi: 10.1016/j.xpro.2025.104146. Epub ahead of print. PMID: 41108683; PMCID: PMC12554168.
The research was supported by the Alan and Irene Adler Ocular Research Initiative and the Mills and Margaret Cox Macula Society Research/Retina Research Foundation.