Each tear type carries unique proteins that reveal insights into health
It’s been said that angry tears are salty and happy tears are sweet. Whether or not that’s actually the case, it is true that not all tears are the same. Tears from chopping an onion are different from those shed from pain – like stepping on a Lego in the middle of the night — as are those special basal tears that keep eyes moist all day. Each type of tear carries unique proteins that reveal insights into health.
Clearly, there’s more to tears than meets the eye. In a new study published in Clinical Proteomics, BYU professor of biochemistry Kenneth Christensen and former grad student Robert Roden detail a groundbreaking way to use soft contact lenses to collect proteins from basal tears for early disease detection.
“How many people could be helped if doctors could catch diseases before symptoms develop?” Roden said. “With this new lens method, we could potentially screen for a range of health issues from analyzing tears.”
Bodily fluids such as tears or saliva contain proteins released from various locations throughout the body. The presence of certain proteins in biofluids can indicate health issues happening in the body. Proteins found in tears are uniquely suited for detecting eye diseases like glaucoma and macular degeneration, but they can also identify systemic diseases such as breast cancer or Alzheimer’s.
The problem is, tears are notoriously difficult to collect. The current methods of tear sampling are painful, irritating to the eye, and mainly produce a type of tear called reflex tears.
“When you poke yourself in the eye, you get a lot of reflex tears,” Christensen said. “But those tears are likely not the ones that indicate disease. Reflex tears would be diluting indicator proteins associated with potential disease in the body.”
Instead of invasive eye pokes, Roden’s idea was to use something more comfortable: a soft contact lens, which is designed to naturally soak up proteins from the eye. Testing showed that lenses made from the hydrogel material Etafilcon-A collected the highest protein levels without causing irritation.
When these contacts were worn by volunteers for just five minutes, they absorbed nearly the same range of proteins as conventional methods, but with less eye irritation to the patient. Also, this new approach allows patients to collect their own tears, eliminating the need to rely on a trained optometrist.
Roden and Christensen both say their work on this project is far from drying up. In collaboration with Rocky Mountain University, the research team is conducting additional clinical trials using the contacts to link specific tear proteins to diseases like Macular Degeneration and cancer. Ultimately, they hope this new method will be implemented in the offices of optometrists and oncologists.
“This project is very powerful in its scope,” Roden said. “Any disease that your blood touches has the potential to show up in your tears. Hopefully this sampling can turn into a routine screening.”
Roden, now a professor at Rocky Mountain University, says completing his PhD at BYU was fulfilling both scientifically and spiritually. He loves the bold intersection of science and religion that is encouraged at BYU. He says he was grateful to study at a place where science and faith are fused together.
“Biochemistry is a witness of our Creator,” Roden said. “Our very molecules declare that the Lord governs all life. Some people say that science and religion are contradictory, but I cannot find anything further from the truth. The fingerprint of God is everywhere in science.”
To read the full publication by Roden and Christensen, visit https://pmc.ncbi.nlm.nih.gov/articles/PMC10936081/
