Tear Meniscus is a thin strip of tear fluid with concave outer surfaces at the upper and lower lid margins. It contains most of the exposed tear volume. The area, radius and height of the tear meniscus are significantly smaller in patients with dry eye.
TBUT (Tear Breakup Time):
Tear breakup time is a clinical test used to assess evaporative dry eye disease. To measure TBUT sodium fluorescein dye is added to the eye and the tear film is observed under the slit lamp while the patient avoids blinking until tiny dry spots develop. The longer it takes, the more stable the tear film. A short tear breakup time is a sign of a poor tear film.
Determining if a patient has dry eye by doing a lid evaluation isn’t the only type of evaluation that needs to be done. The cornea needs to also be evaluated, some of the things we look for or test when evaluating the cornea for dry eye includes: