Injury to the eye's surface provokes an inflammatory response, mediated, in part, by 12-hydroxyeicosanoids. CYP4B1 catalyses the 12-hydroxylation of arachidonic acid (ARA) to 12-HETE and 12-HETrE (12-hydroxy-5,8,10,14-eicosatetraenoic acid and 12-hydroxy-5,8,14-eicosatrienoic acid respectively). Both these metabolites possess potent inflammatory and angiogenic properties (Ashkar et al. 2004). The example of 12-HETE formation only is shown here.