EyeWiki:Featured article/February 1, 2020

From EyeWiki

Featured Article for January 31, 2020

Elevated Episcleral Venous Pressure (EVP)

Elevated episcleral venous pressure (EVP) is a clinical finding which may be associated with elevated intraocular pressure (IOP) and glaucoma if left chronically untreated. In many cases the diagnosis is secondary to an underlying etiology, however it can also be idiopathic if all other causes are excluded. The idiopathic form can be familial or sporadic. In German literature idiopathic elevated EVP leading to secondary open angle glaucoma has been termed Radius-Maumenee Syndrome.

Based on the Goldmann equation, intraocular pressure (IOP) is the rate of aqueous humor production divided by the facility of outflow plus EVP. The average EVP ranges from 8-10 mmHg, although can transiently change based on head positioning. In the acute setting, there is a linear relationship and 1 mmHg rise in EVP correlates to a 1 mmHg rise in IOP. However, this relationship is not as well understood in chronic cases.