Dry Eye Tear Break Up:Tears are a complex tissue consisting of three layers. A mucin layer helps tears adhere to the corneal surface without beading up. An aqueous layer provides actual moisture. A lipid layer floats on top of the aqueous to prevent evaporation. While pathologies may exist in any or all of these layers, one way of assessing the total functioning of the tear film is called tear break up time. Ideally, the tear film covers the entire corneal surface smoothly, without breaking up between blinks. A well functioning tear film is especially important for Lasik patients, because tears can help fill in the valleys or an irregular corneal surface. If the tear film begins to break up, the result is vision quality problems. The simulator below captures one aspect of this experience, namely blurry vision following tear break up.
Directions: A timer will move across the bottom of the simulation. Move the red dot to control the length of time until tears begin to break up. Move the orange dot to determine when blinking occurs.