Angle Closure Associated With a Cobblestone Iris Configuration

Abstract

The purpose of the study was to report a patient with primary angle closure associated with a different nonpupillary block mechanism in which an abnormally thick peripheral iris assumes a cross-sectional shape resembling a cobblestone. This is a case report focussing on clinical and imaging description. Slit-lamp biomicroscopy revealed patent laser peripheral iridotomies OU. The anterior chamber was relatively deep in the center but 360 degrees narrow at the periphery, associated with an abnormally elevated iris contour OU. On dark-room gonioscopy, the angles were occludable with few areas of peripheral anterior synechiae. Anterior segment-adapted spectral domain-optical coherence tomography revealed an unusual iris profile. Despite a flat contour and normal thickness until the mid-periphery, the iris assumed a rectangular cross-sectional shape (resembling a cobblestone) with an abnormal increase in its thickness in the periphery (360 degrees OU). Ultrasound biomicroscopy imaging showed a normal ciliary sulcus and ciliary body configuration, revealing no cysts at 360 degrees. Definitive relief of appositional angle closure was achieved with laser peripheral iridoplasty OU. This unusual anatomic condition of the peripheral iris, which has different characteristics when compared with ordinary cases of thick peripheral iris roll, may lead to angle closure and intraocular pressure elevation despite a patent iridotomy. Clinicians should be aware of this anatomic condition whenever dealing with cases of angle closure.