Some diabetics don't test their blood sugar as often as they should. One of the reasons they cite for not checking their blood glucose as often as recommended is because of the pain it causes. Researchers have been looking into finding ways that are less painful than the finger-prick test; one of these ways has been by using a blood sugar monitor that allows testing on the arm or palm of the hand. But a new device for diabetes makes testing blood glucose levels even less painful: it tests tears instead of blood.

According to a test of 12 rabbits, researchers were able to show a correlation between the glucose levels in tears and those in blood.



Biomedical engineer Jeffrey LaBelle, along with researchers at the Mayo Clinic are developing tear glucose monitoring technology. The device is supposed to work as follows: you test the white of your eye for five second with a sensor, then press a button on the device for your blood sugar reading.



In addition to lower tear volume than blood volume, there is also lower concentrations levels of glucose in tears than blood. This poses a challenge for engineers to develop sensors that are more sensitive to reading blood sugar levels. There's also the issue of tear evaporation to contend with. It's also been noted that the levels of glucose in blood can range from 30 to 50 times less than in blood. Therefore, before using tear glucose monitoring on humans, patients and doctors will need to determine the ratio of glucose in tears as compared to in blood.