The possibility of having more than one pupil in a single eye often sparks curiosity. The pupil, the dark center of the eye, plays a crucial role in vision by regulating the amount of light entering the eye. Its ability to constrict and dilate allows us to see clearly in various lighting conditions.
The Truth About Multiple Pupils
It is extremely rare, but possible, for a person to appear to have more than one pupil in a single eye, a condition known as polycoria. Polycoria is characterized by more than one pupillary opening in the iris. It can affect one eye or both.
There are two distinct types of polycoria: true polycoria and pseudopolycoria. In true polycoria, an individual possesses two or more separate pupils, each with its own intact sphincter muscle. These muscles allow each pupil to independently constrict and dilate in response to light, much like a single normal pupil would. True polycoria is exceptionally rare, with only a few documented cases.
In contrast, pseudopolycoria refers to the appearance of multiple pupils, but only one is a true, functional pupil. The additional “pupils” are actually holes or defects in the iris tissue that resemble pupils but lack their own sphincter muscles. These defects do not react to light independently and are often linked to other eye conditions or iris trauma. Pseudopolycoria is less rare than true polycoria but remains uncommon.
Understanding Polycoria
Polycoria is typically a congenital condition, meaning it is present from birth. The exact cause of polycoria is not fully understood, but it can be associated with abnormal development of the pupil margins or other eye developmental abnormalities. Some cases are linked to conditions such as polar cataracts, glaucoma, or retinal detachment.
The presence of multiple pupils can impact vision due to the irregular way light enters the eye. Individuals with polycoria may experience blurred vision, dim vision, and double vision, also known as monocular diplopia. They might also struggle with glare and light sensitivity, as multiple pupils refract light unusually. The pupils are often smaller than typical and separated by iris tissue, reducing the overall light reaching the retina.
Diagnosis of polycoria typically involves a comprehensive eye examination by an ophthalmologist. This often includes a slit-lamp exam, which uses a special light and microscope to assess the structure and function of the eye and identify any iris abnormalities. While there is no specific cure for polycoria, management often focuses on addressing the visual disturbances it causes, which may include tinted glasses to manage light sensitivity or, in some cases, surgical intervention to improve vision.