Figure 1 illustrates the structures of the iris. Just anterior to the posterior pigmented epithelium lies the sphincter and dilator muscles. The posterior aspect of the iris is comprised of a smooth layer of densely pigmented epithelium that wraps around the pupillary border, creating the pupillary ruff. This radial vascular network is responsible for the bleeding seen in the anterior chamber during trauma to the iris. The vascular network is comprised of the major arterial circle, which is located at the anterior portion of the ciliary body, and the minor arterial circle, which interweaves through the iris stroma. The stroma contains multiple crypts to allow for the passage of aqueous humor into the anterior chamber. The connective tissue, containing collagen fibrils of hyaluronic acid, creates the stroma of the iris and provides the elasticity and stretch noted during surgical manipulation. The iris is mostly comprised of a network of connective tissue, blood vessels, and melanocytes. This article will cover the technique to repair full-thickness iris tears as well as to repair atonic and mydriatic pupils. Furthermore, tears can be full thickness through the iris stroma or partial thickness, involving only the posterior pigment epithelium leading to trans-illumination defects. Tears at the iris root lead to iridodialysis. Tears at the pupillary border can damage the sphincter muscle, thus leading to an atonic, mydriatic, or partially reactive pupil. Trauma to the iris can present in various ways depending on its location and severity. 3.3 Techniques for Repair of Iris Tears.
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