Regulation of Episcleral Venous Pressure
Episcleral venous pressure (EVP) is a primary cause of intraocular pressure (IOP), yet we know little about it. The episcleral blood vessels have nerves, which suggests that EVP is regulated, but we do not know if failure of EVP regulation causes high IOP, or if we can lower EVP with drugs as a new way to treat glaucoma. This project seeks to shed light on the answers to these questions.
High intraocular pressure (IOP) is the main risk factor for glaucoma and lowering IOP is the primary treatment. Episcleral venous pressure (EVP), the pressure of the blood vessels in the sclera, or 'whites' of the eye, is a main determinant of IOP; yet we know little about it, and very few studies address the subject. The episcleral blood vessels have lots of nerves, which suggests that EVP is regulated. We do not know if failure of EVP regulation causes high IOP, or if we can lower EVP with drugs as a new way to treat glaucoma. This project seeks to find out. Our results will provide new insight into a cause of glaucoma and provide a new target for drugs to treat the disease. We will use a new technique to measure EVP and see how EVP changes as test subjects move from sitting to laying down. We will use a new technology to study EVP that overcomes the major limitation of the 'venomanometry' method used in most prior studies. In venomanometry, a topical anesthetic is applied for subject comfort. Topical anesthesia eliminates any chance of studying neural control of EVP, and so this neural control has not been studied before. These studies will identify the nerves that protect the EVP from changes in cerebral venous pressure that occur due to changes in body position. The results of this study may pave the way for development of new therapies designed to lower IOP through regulation of EVP.