Doctors could soon diagnose eye diseases by studying your tears

WENZHOU, China — Doctors may soon be able to screen for eye diseases by analyzing tears, according to a new study. Researchers have developed a nanomembrane system which harvests and purifies tiny blobs called exosomes from tears, which allows them to check for signs of disease.

Dubbed iTEARS, the system could lead to more efficient and less invasive diagnoses for diseases and eye conditions without relying on symptoms alone. Currently, doctors identify diseases by assessing the symptoms a patient reports. However, these can go undetected during their early stages or patients could relay inaccurate descriptions of their problems.

Other methods of testing samples of proteins or genes could improve the accuracy of diagnoses, but they usually take longer and require large sample volumes. Tears are much better suited for samples because doctors can collect the fluid quickly and non-invasively, even if they can only extract a tiny amount at a time.

“Exosomes with membrane structures can encapsulate and protect their cargos, thus becoming a promising source for disease early detection,” researchers write in the journal ACS Nano.

“Tears can be non-invasively and self-collected from patients for exosome analysis. However, the tear-exosome-based disease analysis has rarely been reported so far. Recording exosomes from trace samples for further analysis is necessary in exploring the tear-exosome-based disease world.”

How does iTEARS work?

Dr. Luke Lee, Dr. Fei Liu, and their team wondered if a nanomembrane system originally developed for isolating exosomes from urine and plasma would work for tears. The team modified their original system to handle the low volume of tears.

The new system, called Incorporated Tear Exosomes Analysis via Rapid-isolation System (iTEARS), separated out exosomes in just five minutes by filtering a tear solution over membranes and changing the pressure to stop them from clogging.

Researchers tagged proteins from the exosomes with fluorescent markers while they were still on the device. The team then transferred the proteins to other instruments for further analysis. They also extracted and analyzed nucleic acids. Through this process, they were able to distinguish between healthy people and patients with various types of dry eye diseases.

iTEARS also allowed the researchers to see differences in microRNAs between patients with a condition called diabetic retinopathy and those without any issues, suggesting that the system could help track how disease develop.

The team says the work could lead to a more sensitive, faster, and less invasive diagnosis of various diseases – using only tears.

South West News Service writer Danny Halpin contributed to this report.

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