Two common tests are:1
Tear Break-Up Time (TBUT)
A test that evaluates tear break-up time (TBUT), will give your optometrist or ophthalmologist an indication of whether you have dry eye or not. Tear film in people with Dry Eye will break up faster than in normal eyes and causes the eye to feel uncomfortable
In the TBUT test, dye is added to the eye and the tears are watched by the eye care profession while the patient stops blinking. TBUT is the time it takes between a blink and the development of tiny dry spots in the stained tear film. The longer it takes, the more stable the tear film. If your tear film breaks up in less than 10 seconds, you may have Dry Eye.
This test uses an orange dye applied to the cornea along with a blue light to look for damage that may have occurred to your eye. A piece of blotting paper containing the dye is touched to the surface of the eye. You will be asked to blink, which will spread the dye on the tear film (the layer of tears that covers the cornea [surface of the eye)], providing protection and lubrication for the eye). Your eye care profession will then shine a blue light in your eye. Any problems on the surface of the eye will be stained by the dye and appear green under the blue light.
- Jackson WB. Management of dysfunctional tear syndrome. Can J Ophthalmol. 2009;44(4):385–394.