2020–2021 BCSC Basic and Clinical Science Course™
Chapter 9: Primary Angle Closure
The Primary Angle-Closure Spectrum
Primary Angle Closure
Primary angle closure is defined by the presence of a narrow angle, as in PACS, along with PAS and/or elevated IOP (>21 mm Hg). The angle can close gradually, with a slow increase in IOP as angle function progressively becomes compromised. Even in the absence of synechial angle closure, there can be damage to the trabecular meshwork from appositional iridotrabecular contact, leading to increased IOP. The chronic form of PAC, in which there is gradual, asymptomatic synechial angle closure, is the most common presentation of angle-closure disease.
An LPI is usually necessary to relieve the pupillary block component and reduce the potential for further synechial angle closure. However, there is some debate about performing LPI in an eye with extensive synechiae, as IOP elevation may occur (see Treatment Controversies). Without an iridotomy, closure of the angle usually progresses, making the IOP more difficult to control. Even with a patent peripheral iridotomy, progressive angle closure can occur, and repeated periodic gonioscopy is imperative. An iridotomy with or without long-term use of ocular hypotensive medications controls the disease in most patients with PAC. However, the EAGLE study suggests that in PAC cases with IOP of ≥30 mm Hg, lensectomy may be the preferred treatment (see Treatment Controversies).
Azuara-Blanco A, Burr J, Ramsay C, et al; EAGLE study group. Effectiveness of early lens extraction for the treatment of primary angle-closure glaucoma (EAGLE): a randomised controlled trial. Lancet. 2016;388(10052):1389–1397.
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.