Future directions in non-invasive measurements of tear film surface kinetics.

Purpose: To review the methods for dynamic, non-invasive, and objective assessment of tear film surface quality and to outline their current state-of-the-art and their future potential.

Methods: Among the methods available, high-speed videokeratoscopy, lateral shearing interferometry, and dynamic wavefront sensing are being considered.

Results: The principles of operations, their advantages and disadvantages, and limitations of each method are being outlined. The possible future directions of each method are also discussed.

Conclusions: To gain a better understanding of tear film, its structure and function, it is essential to combine macroimaging technologies with those focusing on tear film microstructure. In this way, one can envisage a clinical device that could help, in future, early diagnosis of dry eye syndrome and development of better materials for contact lenses and eye lubricants.