Anterior Chamber and Iris
Knowing the depth of the anterior chamber and the axial thickness of the lens aids in surgical planning. A shallow anterior chamber may indicate anatomically narrow angles, nanophthalmos, short axial length, an intumescent lens, or weak zonules.
Gonioscopy can be used preoperatively to rule out angle abnormalities, including peripheral anterior synechiae, neovascularization, or a prominent major arterial circle. Use of a 3-mirror lens helps in the evaluation of the lens zonules for traumatic or congenital dehiscence. Gonioscopy is essential if anterior chamber IOL implantation is anticipated.
The presence of iridodonesis or exfoliation at the margin of the undilated pupil may indicate weakened or absent zonular attachments and may affect the surgical plan. In addition, careful examination of the iris is important, because iris coloboma is often accompanied by lens coloboma and localized absence of zonular attachments.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.