Research: Dryness, OST & conjunctival blood flow

A decrease in ocular surface temperature (OST) can cause a perceived sensation of dryness and promote the basal secretion of tear fluid. Therefore, OST is an important physiological parameter for maintaining ocular surface homeostasis and has also been used as an indicator of dry eye, a condition where dryness is the main complaint.

Tear film instability tends to decrease OST, while inflammation tends to increase it owing to the increased friction between the ocular surface and the eyelid. The most common method for clinically assessing inflammation is to evaluate hyperaemia qualitatively by grade; however, recently, a method has been developed to assess red blood cell movement as blood flow.