In an eye without polycoria, the sphincter muscle is a part of the iris that functions to constrict and dilate the pupil. A patient with true polycoria experiences handicapped vision as well as stimulation of the retina in response to bright lights.It is said that the term "true polycoria" is overused, and used correctly when addressing congenital deformations of the iris. Often "true polycoria" is used when it in fact is a case of pseudopolycoria. Pseudopolycoria
Although less rare than true polycoria, pseudopolycoria is still very uncommon. In cases of pseudopolycoria there is a "passive constriction" that differentiates the extra pupil from the true pupil during constriction and dilation. The extra pupil in pseudopolycoria is different than the extra pupil in true polycoria because it shows defects that are independent of the sphincter muscles. Pseudopolycoria is often associated with Seckel syndrome, posterior polymorphous dystrophy, and juvenile glaucoma.Pseudopolycoria consists of splitting of the iris that are not contingent with the sphincter muscles at the root of the iris. Symptoms and diagnosis
When a patient is diagnosed with polycoria, the signs and symptoms shown are associated with ocular and adnexal growth abnormalities. The iris and the pupil become less effective. Signs can be present as a child; however, the patient may be diagnosed later in their life. This condition results in abnormal eye development affecting both eyes or just one.Upon gross examination the patient will typically have excessively long eyelashes. The iris becomes hypoplastic, making abnormally shaped pupils with prominent crypts.
History
Since true polycoria and pseudopolycoria are so rare, there is not much history on the disorders in the tradition of modern western medicine. According to an article published in 2002, there have only been 2 cases of true polycoria since 1966.Early Chinese history names multiple legendary figures as having double pupils, which as a result was led to a beliefs that a child born two double pupils were destined to be a great king or sage. Xiang Yu, Hegemon of Chu, blood brother and later arch nemesis of Liu Bang, the founding emperor of the Han dynasty, was given great esteem due to his prowess in combat and auspicious double pupil. After overthrowing the Qin dynasty together, he was named Hegemon of the loose series of kingdoms he created in its wake, while he gave Liu Bang the remote province of Han. The Civil War that followed called the Chu-Han contention, ending with a Han victory and a legendary last stand by the Hegemon. See also
Eye injury
Iridodialysis
Monocular diplopia
Coloboma


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