Researchers from the Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky 40292, USA found that palmitoylethanolamide lowers the eye pressure via a concentration-dependent enhancement of outflow facility. The maximum effect was 151.08 ± 11.12% of basal outflow facility and was achieved at 30 nM of PEA in a sophisticated model for high eye pressure.
Elevated intraocular pressure (IOP) is one of the major risk factors for glaucoma, a leading cause of human blindness.
They also solved the mechanism via which PEA lowers eye pressure:
Our results demonstrate that PEA increases aqueous humor outflow through the TM pathway and these effects are mediated by GPR55 and PPARα receptors through activation of p42/44 MAPK.
They summerized some of the clinical data on PEA:
PEA has broad-spectrum pharmacologic properties, producing antiinflammatory, analgesic, anticonvulsant, and antiproliferative effects. In human ocular tissues, a previous study has shown that there are lower levels of PEA in the choroid and ciliary body of glaucomatous eyes as compared with normal eyes. Recently, a clinical study has demonstrated that PEA was effective in reducing the increased IOP after the iridotomy procedure. In another clinical trial, PEA was found to significantly reduce IOP in patients diagnosed with primary open-angle glaucoma (POAG) or with ocular hypertension.
Kumar A, Qiao Z, Kumar P, Song ZH. Effects of palmitoylethanolamide on aqueous humor outflow. Invest Ophthalmol Vis Sci. 2012 Jul 3;53(8):4416-25.