Diagnosis From Tears: Can Tears Detect Disease?
Like blood and urine, tears can reflect changes in the body. So what do we know today about diagnosis from tears, and when could these tests enter daily practice?
Tears contain proteins, lipids, metabolites and antibodies. Also, we can collect them easily without touching the eye. For this reason, researchers are studying diagnosis from tears, much like blood and urine tests. Tear tests are already used in some eye diseases, such as dry eye. For systemic diseases like multiple sclerosis, however, the results are promising but still at the research stage. Therefore, these tests are not used in routine diagnosis.
Why diagnosis from tears?
Today, doctors mostly examine blood or urine to diagnose a disease. Sometimes they examine cerebrospinal fluid, for example to diagnose multiple sclerosis. However, collecting cerebrospinal fluid needs a needle in the lower back, which is hard on the patient. Tears, on the other hand, can be collected easily in a few minutes without touching the eye. Moreover, tears come from the eye surface, which is closely linked to the bloodstream and the nervous system.
“Tears are a sample that can show changes in our body, like blood, urine or fluid taken from the back. Studies on diagnosing diseases with tear biomarkers continue, and we follow the developments with excitement.”
— Prof. Dr. Fırat Helvacıoğlu, from his video explanation
Diagnosis from tears: is it possible?
Prof. Dr. Fırat Helvacıoğlu explains whether diseases can be diagnosed from tears.
Could tears become a “liquid biopsy”?
Tears contain proteins, lipids, metabolites and antibodies, and we can collect them easily without touching the eye. Researchers are studying whether changes in tears reflect diseases of the eye and of the body.
- Sample collectionA thin strip or a capillary tube placed under the lower eyelid collects tears in a few minutes without touching the eye.
- ContentTears contain many different proteins and molecules. Researchers examine changes in their amounts as “biomarkers”.
- ResearchBesides eye diseases, studies also continue on some nervous system diseases and cancers.
What is known about diagnosis from tears today?
One review article compiled studies on tear content. It reported different proteins in the tears of people with dry eye, Sjögren syndrome, contact lens use, glaucoma, diabetic retinopathy and some cancers. The authors stress that tear analysis is promising. First, it helps us understand how diseases develop. Second, it may lead to new diagnostic methods.
- In eye diseases: Doctors already use some tear-related measurements in the diagnosis and follow-up of dry eye.
- In systemic diseases: Studies on diabetes, nervous system diseases and cancers continue. However, these tests are not yet in routine use.
Nervous system diseases and diagnosis from tears
In one study of patients with multiple sclerosis (MS), researchers identified 185 different proteins in tears. One of them, alpha-1 antichymotrypsin, was higher in the tears, cerebrospinal fluid and blood of MS patients. Therefore, the researchers suggested that this protein could one day be a marker measured in tears to diagnose MS.
Such findings are exciting. Still, they come from early studies in small groups of patients. Before a test can be used in diagnosis, researchers must confirm it in much larger and more varied groups.
Limitations
- The amount of tears is very small, so the way we collect them can affect the result.
- Tear content changes during the day, and also with dry eye, contact lenses and environmental factors.
- Measurement methods need to become standard across laboratories.
- Large-scale studies must confirm the markers found for systemic diseases.
What is next for diagnosis from tears?
As technology advances, we can measure thousands of molecules in very small fluid samples. For this reason, tears may one day become a screening or follow-up tool for some diseases. For now, however, doctors keep using standard diagnostic methods if a systemic disease is suspected.
If you have complaints about the eye surface or tears, you can read “Why do your eyes get dry in winter?” and “Why do your eyes water?”.
Frequently asked questions
Doctors use tear measurements in some eye diseases. For systemic diseases, however, tear tests are still at the research stage and are not used in routine diagnosis.
We collect them in a few minutes; no pain is expected during the procedure. A thin paper strip or a capillary tube placed under the lower eyelid does this.
Studies showed that some proteins differ in the tears of MS patients. However, these findings have not yet become a test that doctors can use for diagnosis.
Besides water and salts, tears contain proteins, lipids, metabolites, antibodies and RNA fragments. Their amounts can differ with changes in the eye and the body.
It is not possible to give an exact date. Researchers must first confirm the findings in large patient groups, and measurement methods must become standard.
Related pages
References
- von Thun und Hohenstein-Blaul N, Funke S, Grus FH. Tears as a source of biomarkers for ocular and systemic diseases. Exp Eye Res. 2013;117:126-137. doi:10.1016/j.exer.2013.07.015
- Salvisberg C, Tajouri N, Hainard A, Burkhard PR, Lalive PH, Turck N. Exploring the human tear fluid: discovery of new biomarkers in multiple sclerosis. Proteomics Clin Appl. 2014;8(3-4):185-194. doi:10.1002/prca.201300053
- Craig JP, Nichols KK, Akpek EK, et al. TFOS DEWS II Definition and Classification Report. Ocul Surf. 2017;15(3):276-283. doi:10.1016/j.jtos.2017.05.008
This article is for patient information only. It does not replace an examination or medical evaluation. Your treatment is decided after an eye examination and measurements. Publication date: September 25, 2026.
Contact Prof. Dr. Fırat Helvacıoğlu with your questions
Prof. Dr. Fırat Helvacıoğlu · Veni Vidi Eye Clinic, Bağdat Cad. No: 257, Caddebostan – Kadıköy / Istanbul