Polycoria is an eye condition that affects the pupils. Polycoria can affect just one eye or both eyes. It’s often present in childhood but may not be diagnosed until later in life. There are two types of polycoria. These types are:

  • True polycoria. You will have two or more separate pupils in one eye. Each pupil will have its own, intact sphincter muscle. Each pupil will individually constrict and dilate. This condition can affect your vision. It’s extremely rare.
  • False, or pseudopolycoria. You have the appearance of two or more pupils in your eye. However, they do not have separate sphincter muscles. In pseudopolycoria, the holes in your iris look like additional pupils. These holes are usually just a defect of the iris and do not cause any issues with your vision.

The symptoms of polycoria are usually a product of having more than one set of iris muscles. The iris is the colored ring of muscle around each pupil. It controls how much light is allowed into the eye. In polycoria, the pupils tend to be smaller than normal and separated by individual segments of iris. This can mean less light enters your eye, which can dim your vision. You may also have difficulty focusing because the pupils aren’t working effectively.

The primary sign of polycoria is the appearance of two pupils. Other signs and symptoms may include the following:

  • blurred vision in the affected eye
  • poor, dim, or double vision in the affected eye
  • oblong shape of one or all additional pupils
  • issues with glare
  • a bridge of iris tissue between the pupils

The underlying cause of polycoria is not known. However, there are some conditions that have been associated with it, such as:

  • detached retina
  • polar cataracts
  • glaucoma
  • abnormal development of the pupil margins
  • abnormal eye development

Some people with polycoria do not need any treatment because their vision is not affected enough to require it. For those whose vision becomes difficult because of the conditions, surgery is one possible treatment option. However, because true polycoria is so rare, it can be difficult to determine the best treatments for it.

One case study has shown that surgery was a successful treatment option. This type of surgery is called pupilloplasty. During a pupilloplasty the surgeon cuts through the tissue of the iris, getting rid of the “bridge” that has formed between the two pupils. The surgery, in this case, was successful and improved the patient’s vision.

More trials are needed to determine whether a pupilloplasty will be successful for everyone with true polycoria. However, with the rare nature of true polycoria, there haven’t been enough cases to determine a success rate for this treatment option.

The complications of polycoria include blurred vision, poor vision, and vision difficulties from the glare of lights. These complications of polycoria are due to a less effective iris and pupil.

Pseudopolycoria, or holes in the iris that look like additional pupils, can be a part of Axenfeld-Rieger syndrome. Axenfeld-Rieger syndrome is a group of eye disorders that can affect eye development.

The outlook for polycoria is generally good. You may not require any treatment if your visual impairment is minimal and doesn’t interfere with your daily life. However, if treatment is needed, pupilloplasty has so far shown positive results.

If you have polycoria, it’s important to have regular check-ups with an eye doctor to monitor your vision and any changes your eyes may have. Having your eyes checked regularly is also beneficial for your eyesight as a whole.