Impact of salivary stimulation on tear film function in dry eye subjects

Dry eye is a common condition affecting people worldwide. It causes ocular discomfort by reducing the quality of vision and impacts daily activities. To overcome such ocular discomfort, artificial tears are used but it is difficult to use artificial tears every time to protect eyes from dryness. There is a need to explore other treatment options, which can be used during work hours. The aim was to study the effect of salivary stimulation on tear film functions among dry eye subjects.

Thirty-three subjects were enrolled in this prospective experimental study. Tear film function tests such as tear break up time (TBUT), tear meniscus height (TMH), and Schirmer's I and II tests were conducted. For dry eye subjects, salivation was induced by giving a tamarind candy (a soft slightly sour tamarind pulp mixed with sugar) for 5 min. Tear film function tests were carried out within a few seconds (2 to 3 s) after finishing the candy and then after 30 and 60 min of the induction of salivation. The pre- and post-tear film function measurements were recorded and analyzed.

TBUT, TMH, and Schirmer's II tests showed statistically significant (P < 0.05) increase immediately and after 30 min of stimulation of salivation for all tests in both eyes. However, the difference was insignificant after 60 min of stimulation of salivation. Schirmer's I showed statistically significant changes in the left eye, but not in the right eye immediately after stimulation of salivation (P = 0.025).

The quantity as well as the quality of tear film improved after the stimulation of salivation among dry eye subjects.