Accessory iris membrane is a rare congenital anomaly resulting from hyperplasia of the superficial layer of the iris. It presents as an additional layer of iris tissue giving the impression that the iris is duplicated.
Created by Alex Hirsch. With Jason Ritter, Alex Hirsch, Kristen Schaal, Linda Cardellini. Twin siblings Dipper and Mabel Pines spend the summer at their uncle's tourist trap in the enigmatic town of Gravity Falls.