Microscopic particles in teardrops offer intel on what’s going on in the body. Human tears could carry a flood of useful information. With just a few drops, a new technique can spot eye disease and even glimpse signs of diabetes, scientists report July 20 in ACS Nano.
Your doctor may measure your tear production using the Schirmer test. In this test, blotting strips of paper are placed under your lower eyelids. After five minutes your doctor measures the amount of strip soaked by your tears.
Most people have eye problems at one time or another. Some are minor and will go away on their own, or are easy to treat at home. Others need a specialist’s care.
Whether your vision isn’t what it used to be, or never was that great, there are things you can do to get your eye health back on track.
See if any of these common problems sound familiar. And always check with a doctor if your symptoms are really bad or don’t clear up within a few days.
Eyestrain:
Anyone who reads for hours, works at a computer, or drives long distances knows about this one. It happens when you overuse your eyes. They get tired and need to rest, just like any other part of your body.
Red Eyes:
Their surface is covered in blood vessels that expand when they’re irritated or infected. That gives your eyes the red look.
Night Blindness:
Is it hard to see at night, especially while driving? Is it tough to find your way around in dark places, such as movie theaters?
Lazy Eye:
It happens when one eye doesn’t develop properly. Vision is weaker in that eye, and it tends to move “lazily” around while the other eye stays put. It’s found in infants, children, and adults, and rarely affects both eyes.
Cross Eyes (Strabismus) and Nystagmus:
If your eyes aren’t lined up with each other when you look at something, you could have strabismus. You might also hear it called crossed eyes or walleye.
Colorblindness:
When you can’t see certain colors, or can’t tell the difference between them (usually reds and greens), you may be colorblind. It happens when the color cells in your eye are absent or don’t work.
Uveitis:
This is the name for a group of diseases that cause inflammation of the uvea. That’s the middle layer of the eye that contains most of the blood vessels.
Presbyopia:
This happens when you lose the ability, despite good distance vision, to clearly see close objects and small print.
Floaters:
These are tiny spots or specks that float across your field of vision. Most people notice them in well-lit rooms or outdoors on a bright day.
Dry Eyes:
This happens when your eyes can't make enough good-quality tears. You might feel like something is in your eye or like it’s burning. Rarely, in severe cases, extreme dryness can lead to some loss of vision.
Excess Tearing:
It has nothing to do with your feelings. You might be sensitive to light, wind, or temperature changes. Try to protect your eyes by shielding them or wearing sunglasses.
We wanted to demonstrate the potential of using tears to detect disease, says Fei Liu, a biomedical engineer at Wenzhou Medical University in China. It’s possible the droplets could open a window for scientists to peer into the entire body, he says, and one day even let people quickly test their tears at home.
Like saliva and urine tears contain tiny sacs stuffed with cellular messages (SN: 9/3/13). If scientists could intercept these microscopic mailbags, they could offer new intel on what’s happening inside the body. But collecting enough of these sacs, called exosomes, is tricky. Unlike fluid from other body parts, just a trickle of liquid leaks from the eyes.
So, Liu’s team devised a new way to capture the sacs from tiny volumes of tears. First, the researchers collected tears from study participants. Then, the team added a solution containing the tears to a device with two nano porous membranes, vibrated the membranes and sucked the solution through. Within minutes, the technique lets small molecules escape, leaving the sacs behind for analysis.
The results gave scientists an eyeful. Different types of dry-eye disease shed their own molecular fingerprints in people’s tears, the team found. What’s more, tears could potentially help doctors monitor how a patient’s diabetes is progressing.
Now, the scientists want to tap tears for evidence of other diseases as well as depression or emotional stress, says study coauthor Luke Lee, a bioengineer at Harvard Medical School. “This is just the beginning,” he says. “Tears express something that we haven’t really explored.”
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