While there are many medical conditions that affect the eyes, none are quite like aniridia, a condition that can dramatically impair eyesight. With aniridia, the iris, or the colored band that surrounds the pupil, is either missing or partially missing. This can lead to impaired vision and extreme discomfort in sunlight when too much light enters the eye. Thankfully, treatment is now available through the surgical implantation of an artificial iris.
What Is Aniridia?
Aniridia is a condition that occurs when someone is missing all or part of his/her iris. Sometimes, both eyes are affected at the same time, typically, when the condition is present at birth (congenital aniridia). However, trauma can also cause aniridia where typically just one eye is involved.
What Is the Iris?
The amount of light that comes in through the pupil (the hole in the center of the eye that lets in light) is controlled by the iris. The iris is the colored part of the eye that expands and contracts, changing the size of the pupil. When outdoors in the sun or in a brightly lit room, the iris will contract and limit the amount of light entering the eye. When the room is dark, the iris expands to make the pupil bigger in order to see better in low light. As one can see (no pun intended), the iris plays an important role in vision. Without the iris, the light is completely uncontrolled, much like an overexposed photograph.
What Causes Aniridia?
The two main causes of aniridia are genetics and injuries. While extensive studies have been done that pinpoint the exact chromosomal issues that lead to aniridia, injuries are a more common cause. Any penetrating eye injury from a fall, car, or work accident can cause partial or even total loss of the iris.
The genetic causes of aniridia involve chromosome 11 and a gene, PAX6. Defects in this gene cause a person to be born with aniridia. If someone who carries the gene has a child, then the child has a 50% chance of inheriting aniridia. However, a person can be born with aniridia even if there’s no family history of the condition. This is called sporadic, and aniridia occurs without warning. Regardless, anyone with aniridia will have vision problems, based on the extent of the aniridia and any other associated eye issues with the cornea, the optic nerve, or the retina.
Although the lack of an iris is apparent in anyone with aniridia, an ophthalmologist must make the diagnosis. They will be able to see if there are any other defects in the eyes as well, and will be the ones to make the decision of how to treat the aniridia.
Are There Treatments?
The recent answer to this question is yes. An exciting new FDA approved treatment for aniridia is the artificial iris. It is officially called the Humanoptics CustomFlex Artificial Iris, and is often the best treatment for aniridia. The artificial iris is a revolutionary innovation. It is implanted into the eye, where it does the job of the missing iris. It is made of medical grade silicone and is custom created by artists to look like a natural colored iris, greatly enhancing the appearance of the eye. While this cosmetic feature is certainly desirable, what is most important is that the artificial iris dramatically reduces glare, eliminating the most severe symptom caused by aniridia. Special contact lenses, cataract removal, and a number of additional eye treatments can help the other conditions that go along with aniridia.
How Is An Artificial Iris Implanted?
The procedure to implant an artificial iris is done by an ophthalmologist who has undergone special surgical training with this device. Not all eye surgeons have this expertise. The artificial iris is inserted through an incision in the eye and placed under the cornea where the pupil would be (or is, depending on the patient). If a cataract is removed, the artificial iris can be placed in the eye along with the new lens implant. In many cases, especially post-traumatic anirida, there is no support for the iris prosthesis so it has to be secured to the walls of the eye with permanent Gore-Tex sutures.
Another great feature about the artificial iris is the fact that it is custom made. This means that any eye color can be selected, and it will be trimmed to size ensuring a proper fit and a close match to the unaffected eye.
Aniridia and the Artificial Iris
In summary, people with aniridia are either born without the iris of their eye, or the iris is partially missing or damaged from trauma or infection. This leads to a number of vision problems, including an inability to adjust the amount of light that gets into the eye, similar to having your eyes dilated at the doctor’s office. As a result, people with aniridia can have very poor vision and disabling glare. In such cases, the artificial iris is indicated. It is the only FDA approved treatment for aniridia in the country and has been proven in a national study to be safe and effective in reducing the symptoms of aniridia.