There is not any known direct mechanisms involved in the development of true<unk>  or pseudopolycoria. There are some proposed ideas, one being that after the sphincter muscle is fully formed and developed in the eye there is a severing of the pupillary margins leading to the distinction of the extra pupil and the principal pupil.<unk>  can also be caused any hole in one's iris to develop a sphincter muscle development. Another proposed theory about the cause of<unk>  is intrauterine trauma, or postpartum iris trauma. If the development of the iris is hindered, the ectoderm of the eye (which forms the lens and corneal epithelium) may split, which could lead to pseudopolycoria.
Polycoria
Heterophoria
Orthophoria
Esophoria
Exophoria
Binocular dysphoria
Astigmatism
Astigmatism 