The iris should be examined before pupillary dilation. The clinician should note heterochromia, iris atrophy, ectropion uveae (the presence of pigmented iris epithelial cells on the anterior iris surface), corectopia (displacement of the pupil), nevi, nodules, exfoliative material, transillumination defects, the presence and patency of an iridotomy or iridectomy, and any surgically induced iris abnormalities. Iris color should be noted, especially in patients being considered for treatment with a prostaglandin analogue.
Early stages of neovascularization of the anterior segment may appear as either fine tufts at the pupillary margin or a fine network of vessels on the surface of the iris adjacent to the iris root. The clinician should also examine the iris for evidence of ocular trauma, such as iris sphincter tears, iridodialysis (tear in the iris root), or iridodonesis (abnormal iris motion caused by poor or absent lens zonular support).
The contour of the iris can provide clues about the underlying mechanism of angle closure and the presence of pigment dispersion syndrome. Irregularities in the iris contour may suggest choroidal effusion or hemorrhage. Other conditions that can cause irregularity of the iris contour include an iris or ciliary body cyst or, rarely, uveal melanoma; ultrasonography is required to characterize such lesions, and either type can lead to IOP elevation.
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.