Understanding Polycoria: Is Two Pupils in One Eye Possible?
August 9, 2024 • 6:02 PM
Polycoria is an extremely rare condition that causes someone to develop more than one pupil in the iris of each eye. There are two main forms of polycoria: true polycoria and psudopolycoria, with true polycoria being much more rare.
We’d be prettysurprised if you’ve met someone with true polycoria —but maybe you have. Either way, we’re bringing you the facts about this condition and the circumstances that might be behind its development.
What Is True Polycoria?
When people talk about polycoria, they’re generally talking about true polycoria — the development of a full second pupil within a person’s eye.
This extra pupil has its own sphincter muscle, which is the mechanism that makes it constrict and dilate in response to different levels of light.
What Is Pseudopolycoria ?
When someone has pseudopolycoria, they don’t truly have a second pupil in their eye — instead, they might have pseudo-pupils, which are extra openings in the eye that look similar to real pupils.
These openings can result from holes in a person’s iris, which sometimes develop after surgery or because of an eye disease.
How Do People With Polycoria See?
Someone with polycoria has two pupils next to each other, affecting how their eyes perceive light. The main job of the pupil is to control the amount of light that enters your eyes. As a result, having two independently functioning pupils can make this job extra complicated.
The two pupils don’t respond to light in a coordinated or synchronized way, potentially leading to glare and halo effects around bright lights.
People with polycoria often also have some visual distortion, meaning they don’t see things exactly as they are. Light entering through multiple pupils can cause light to refract in strange ways, which sometimes leads to double vision or issues with depth perception. Some people with polycoria might squint a lot or avoid bright lights to help manage these symptoms, while others turn to tinted glasses or sunglasses for help.
Polycoria symptoms can affect your life in a big way. However, the severity of the effects of polycoria can vary, and one person with the condition might not need to adjust their lifestyle much, while another person might need surgery.
If you have polycoria, the best way to improve your quality of life is to talk to an eye doctor — handling the condition on your own can be lonely, frustrating, and sometimes even risky.
What Causes Polycoria?
Sadly, we don’t know much about polycoria (yet). Because the condition is so rare, research is currently very limited. That said, we do know that there are several potential causes of pseudopolycoria.
First, pseudopolycoria can stem from another condition called iris coboloma. Someone with iris coboloma is missing a portion of the iris in one of their eyes, which can make it look like they have multiple pupils.
People with cobolomas tend to have them from birth, and the condition is sometimes misidentified as true polycoria. However, it’s much more common to have a coboloma than to have true polycoria.
In addition, eye trauma can lead to iris damage, which can, in turn, cause pseudopolycoria. When someone gets a serious eye injury, their iris might form additional openings that look like pupils. However, these aren’t actual additional pupils — which means this is still a case of pseudopolycoria rather than true polycoria.
Iris atrophy or macular degeneration, two eye diseases, can also sometimes contribute to pseudopolycoria — but macular degeneration itself does not cause pseudopolycoria. In these cases, small tears form in the iris, similar to those caused by eye trauma. Unfortunately, surgeries used to treat some eye diseases can also accidentally create these tears.
How Rare Is Polycoria?
Only a few cases of true polycoria have been recorded.
The condition is so rare that we don’t have much information about its root causes. We do know, though, that most people aren’t diagnosed with polycoria until they reach adulthood, and that it’s often mistaken for other conditions in childhood and adolescence.
How Is Polycoria Diagnosed?
The only way to know if you have polycoria is to get help from an ophthalmologist or optometrist. They might use a few tests, including a silt-lamp exam, an ophthalmoscopy, and imaging, to look for signs of polycoria.
Once you are diagnosed, your eye doctor can help you determine the best way forward. If you have pseudopolycoria, treatment might center around management strategies rather than surgery or medicine. Some of the most common treatments for pseudopolycoria are eye drops or prescription glasses to help with light sensitivity or eye irritation.
Does Polycoria Have Symptoms?
People with both pseudopolycoria sometimes have uncomfortable symptoms, but the symptoms of true polycoria are usually more severe and might call for surgery.
Polycoria often causes light sensitivity, which can be uncomfortable and interfere with a person’s day-to-day life. For example, people with polycoria generally struggle to drive without help from eyedrops, sunglasses, or, in extreme cases, surgery.
In addition to light sensitivity, people with polycoria often experience blurred vision under some circumstances. This symptom might correspond with light — more intense light might cause a person’s vision to go blurry. If this symptom becomes especially hard to manage, surgery might be the best way to find relief.
One of the other symptoms that eye doctors often notice is a bridge of iris tissue between the two pupils in one eye. During a pupilloplasty (the surgery used to treat polycoria), this tissue gets removed, removing the bridge between the two pupils.
Since this tissue is thought to be one of the primary causes of blurred vision from polycoria, some doctors think it might be the best treatment for patients with serious trouble seeing. However, more research still needs to be done before we know for sure.
Is Polycoria Treatable?
Not everyone with polycoria gets treatment for the condition. However, polycoria sometimes causes vision issues, especially blurry or double vision.
If the condition seriously hinders a person from living life to the fullest, the only treatment option is surgery to join the pupils. This procedure is called pupilloplasty, and it’s used to repair any form of damage to a person’s iris.
In cases of true polycoria, surgery is the only form of treatment that’s effective enough to be recommended by doctors. Surgeries for treating polycoria involve fusing the two pupils, which can improve a person’s ability to see both close up and far away. However, whether or not surgery is worth it to treat your polycoria is between you and your eye doctor.
Does Polycoria Always Need Treatment?
Pseudopolycoria doesn’t typically affect a person’s vision, so there’s often no need for surgery or any other form of treatment. If you have pseudopolycoria, the best path forward is to embrace your unique eyes and make them a part of your one-of-a-kind look.
One of the most important aspects of living well with pseudopolycoria is sticking to a consistent schedule of eye doctor appointments. Your optometrist can help you monitor your symptoms and advise you about potential treatment options if needed. Plus, regular eye exams will help you spot other conditions and diseases early and prevent them from worsening.
Is Polycoria Linked to Other Conditions?
People with polycoria often have other eye conditions. Some common coexisting conditions for polycoria are glaucoma, a detached retina, polar cataracts, and abnormally long eyelashes.
Glaucoma is an eye condition that can cause vision blurring and loss, and it’s much more common than polycoria. However, both conditions have overlapping symptoms and can impact the appearance of your pupils, so you might misidentify your glaucoma as polycoria. Make sure to get help from an optometrist instead of trying to self-diagnose.
Some of these conditions require surgery and other more intensive forms of treatment. However, after an initial operation or prescription, many people can manage their symptoms with regular visits to the eye doctor.
The Bottom Line on Polycoria
Polycoria is incredibly rare, but if you do have one of the forms of this condition, there’s help available. Folks with true polycoria may benefit from corrective surgery, but pseudopolycoria often doesn’t require any treatment at all.
If you notice any issues with your irises or your eyes, it’s always smart to visit your eye doctor and get a clearer perspective on what’s happening. That way, you can have peace of mind knowing you’ve talked to someone who knows how to identify more serious eye issues.
Sources:
[Polycoria and pseudopolycoria] | NCBI
Relief of symptomatic pseudo-polycoria due to iris biopsy using a daily contact lens | PMC