Tears and saliva have a similar structure as they are mostly made of water but also contains chemicals and over 1,500 proteins. Tears also contain electrolytes like sodium that gives its salty taste, bicarbonate, chloride, and potassium. It even has calcium and magnesium.
They are also like the blood that delivers oxygen and nutrients to the eyes, remove waste. Tears also serve as the first line of defense against bacteria and heal injuries.
The various chemicals present in tears and blood serve as biomarkers that can be used in detecting illnesses. For example, high levels of glucose in the blood signals for diabetes or liver disease because of the unusual levels of some enzymes. This is the main reason why doctors order blood tests but perhaps in the future, tears can be used to look for indicators of diseases.
TearExo Can Be Used to Detect Breast Cancer
Breast cancer is diagnosed through mammography, a piece of equipment so bulky that it takes time to arrive at a diagnosis. According to BioMed Advances, researchers from Kobe University made a technology that can detect breast cancer without using mammography.
This new technology is called the TearExo, wherein a glass chip with an antibody to the cancer cell exosome could detect proteins of the exosome present in tears. The glass chip will tell whether there is cancer present in the tear or not. It is very sensitive as it can detect around 50 exosomes in a 100µL tear sample in just ten minutes.
Therefore, just by analyzing the chemical components present in tears, the TearExo could easily and quickly diagnose if a patient has cancer.
Read Also: Doctors Can Use Selfies To Detect Cardiovascular Diseases
Tear Testing's Impact in COVID-19
According to an article by Scientific American, tears can someday save people's lives by early detection of diseases, and that includes COVID-19. Tear testing could make an impact on the diagnosis of COVID-19, which is typically done with blood or swab tests.
But research suggests that the coronavirus RNA can also be found in tears and that antibodies for coronavirus can also be measured from tears. In that case, a tear test could be developed in the future which is cheaper and do not involve any needles. This, too, can be self-administered at home.
More Than Testing
Biomarkers in tears are more than just for testing. For instance, the tear-based technology of a smart contact lens closely monitors the biomarkers of the patients and significantly improve disease prevention and early detection of devastating diseases.
Major companies, such as Novartis and Google was attracted by this technology and is currently researching it in their laboratories. Their first stand-alone contact lens was developed in 2019, and the most recent one was developed for monitoring glucose levels and as a diabetic retinopathy treatment.
More so, NASA has also proposed to use tear markers to monitor the health of astronauts while they are in space as it would allow a better understanding of the effects of long-term exposure to space on humans. Their results could be used to establish a health database that could be a stepping stone towards making space colonization possible.
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