How Salty Are Your Tears? Why Does That Matter?

TEAR OSMOLARITY, the measurement of the saltiness or salinity of your tears, is an important measurement of the health of your tears and your eye lubrication. As you know, tears are a complex combination of salt water, mucin, and special oil called mebum. All three of these elements or ingredients are mixed up, kind of like Italian salad dressing, and they form the tears that coat the surface of our eyes every minute of every day. As an aside, the tears that we make when we cry, or when something gets in our eyes, are almost completely salt water.

The measurement of your tear osmolarity is a rather new test. It's fully FDA approved. When your tear saltiness is high this is an indication that your tears are not normal. Now, you may not have any symptoms when this is the case, but we usually only do the Tear Osmolarity test when you tell us that your eyes are not comfortable! At Skyvision Centers we use the most modern instrument made by the TearLab corporation to do your test.

Why is this an important measurement? Well, the two most important causes of a Dry Eye, or dry eye symptoms are problems in the production of either the salt water part of your tears, or in the production of the oil or lipid part of your tears. If you have a HIGH Tear Osmolarity it is most likely that your problem stems from something wrong with the production of the salt water in your tears. Either you are not making enough, or what you are making is not working well enough. A LOW Tear Osmolarity does not mean that you don't have Dry Eye Syndrome, it simply means that some other factor is the underlying cause.

The best research available right now shows that a Tear Osmolarity of under 300 is probably normal, or at least "normal enough"! Anything over 308 is abnormal. Measurements between 300 and 308 have to have some additional information from your exam to be meaningful. We will always tell you your number!

As far as we know Skyvision Centers was the first eye center in Northeast Ohio to use Tear Osmolarity in the care of Dry Eye.