Diffuse Iris Nevus. Iris nevi typically appear as hyperpigmented regions of the iris with minimal disruption of the normal iris architecture. However, they may occasionally be associated with ectropion uveae or sectoral cataract. There are two types of iris nevi. Circumscribed iris nevi are discrete and often nodular. Diffuse iris nevi, as shown in this photograph, involve an entire sector or rarely the entire iris.