Since the cornea is extremely well innervated and highly sensitive to stimuli, the presence of lipid species related to platelet‐activating factor (PAF) and/or lyso‐phosphatidylcholine, phosphatidylcholine, and sphingomyelin in both the normal and dry eye rabbit tears,113 may be involved in causing ocular pain during injury, trauma, dry eye and in other conditions of ocular surface irritation as in SAC/PAC. This evidence concerns the gene PCLAF and dry eye syndrome.