P2Y2 receptors belong to the family of G-protein coupled receptors and are activated by nucleotides such as ATP and UTP.1,2 Activation of P2Y2 receptors (P2Y2-Rs) on various epithelial cell types enhances chloride, fluid and mucin secretion and thereby stimulates the body’s natural mucosal lubrication and clearance mechanisms.3,4 On the ocular surface, P2Y2-R mRNA is localized in various epithelial cells in the eyelid, cornea and conjunctiva. Previous work using conventional non-isotopic in situ hybridization techniques demonstrated localization of P2Y2-R mRNA in the palpebral conjunctiva of the eyelid, the epithelium of the lid margin and the meibomian gland; the corneal epithelium and adjacent bulbar conjunctiva, particularly the conjunctival goblet cells.5