Measurement of Uveoscleral Outflow Rate
Uveoscleral outflow rate cannot be measured noninvasively and, therefore, is usually calculated from the Goldmann equation after determination of the other parameters. There is evidence that outflow via the uveoscleral pathway is significant in human eyes, accounting for up to 45% of total aqueous outflow, although invasive studies using tracers tend to report lower values. Some studies indicate that uveoscleral outflow decreases with age and is reduced in patients with glaucoma. It is increased by cycloplegia, adrenergic agents, and prostaglandin F2α analogues but decreased by miotics. It is also increased by suprachoroidal stents and by cyclodialysis clefts.
Bill A, Phillips CI. Uveoscleral drainage of aqueous humour in human eyes. Exp Eye Res. 1971;12(3):275–281.
Brubaker RF. Measurement of uveoscleral outflow in humans. J Glaucoma. 2001;10(5 Suppl 1): S45–S48.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.