Pupillary disorders.

This chapter provides a comprehensive overview of various conditions affecting the pupil, encompassing anatomic, developmental, and pathologic aspects. The relevant anatomy and embryology of the iris is described, highlighting the sphincter and dilator pupillae muscles which control pupil size. A few examples of iris pathologies (congenital and acquired) are given for illustrating ocular disorders which affect pupil size and shape. The majority of this chapter discusses the autonomic pathways, parasympathetic and sympathetic, to control pupillary movement. Included are details of the anatomic pathways in the brainstem, in the orbit, and around to eye, as well as points of debate regarding the anatomy. Finally, the clinical manifestations of a sympathetic and parasympathetic deficit to the eye are presented with clinical examples.