Table 2.

Consensus group proposal for tear substitute terminology and properties of each category of agent [21]

Wetting agents	Multiple-action tear substitutes	Ocular surface modulators
Lubricate the ocular surface	Improve quality and quantity of tear film components	Polymers
Limited residence time	Limited capacity to interact with ocular surface epithelia	Capacity to interact with and influence ocular surface components
		Promote ocular surface homeostasis
		Promote healthy cellular functioning
		Eventually modulate the inflammatory process

From Barabino et al. [21]