Stability of the precorneal tear film

Abstract

A stable tear film is prerequisite for the proper functioning optical and metabolic eye. High percentage of conditions associated with dry eye, complications due to use of contact lenses and alterations of the tear are generally related to the instability of the tear film. Therefore, it is important to know and understand the terms related to tear stability, phenomena involved in different proposed theories and techniques to evaluate it, in order to make more accurate diagnosis, enabling effective treatments. Based on This literature review it will present models to explain the tear stability and instability to have a broader view of this important physico-chemical phenomenon unknown and even less understood by visual and ocular health professionals.