Aniridia is the partial or complete absence of the iris, which is the colored part of your eye. The iris regulates the amount of light that enters your eye. In low light conditions the pupil, or opening in the center of your iris, increases in size to let in more light. Conversely, in bright light, the pupil constricts to reduce the amount of light entering your eye.
What causes aniridia?
Sometimes the iris fails to develop properly due to a genetic defect – this is known as congenital aniridia. Aniridia can also result from trauma to the eye, because the iris is quite fragile – like the consistency of tissue paper.
Aniridia usually causes light sensitivity and problems with glare, similar to what we all temporarily experience when we leave a movie matinee and step outside into the bright afternoon sunshine. This is because the lack of iris tissue allows too much light into the eye. In addition to causing light sensitivity, aniridia can also make it difficult to open the eye normally, and it reduces the depth of field normally provided by a small or medium pupil (similar to the aperture effect in a camera).
Often surgeons can repair a traumatic iris defect with sutures. When iris repair is not feasible, an artificial iris can help provide relief from light sensitivity and glare.
The Cornea Research Foundation and Price Vision Group have long had an interest in helping aniridia patients and are currently able to help treat patients with an artificial iris, read more here.
A Patient Story
A five-year-old New York boy has came to Indianapolis for a chance to dramatically improve his vision. Michael Cruz was born with troubled eyes. He does not have any irises - the part that would usually be blue, brown, green or hazel. The iris controls the amount of light that enters the eye. It is a ring-shaped tissue with a central opening, which is called the pupil.
In a normal eye, the pupil will constrict in bright light and dilate in dimmer light. For Michael, light in an ordinary room is too bright to see clearly because his eyes can’t filter it.
“Kind of like coming out of a movie matinee in the bright sun—you know how just devastating it is—you can’t keep your eyes open, you can’t lift your head up. And that’s the way these people are all the time from the time they’re born. So Michael doesn’t even realize what it’s like not to be that way,” said Dr. Francis Price, eye specialist.
Soon, though, Michael should see the world with new eyes. An operation he had at St. Vincent Hospital Tuesday morning gave him an artificial iris. He’s only the third child in the country to get such an implant.
“The artificial iris has a clear central area that’s visual, and an outer area that’s nine millimeters in diameter that’s opaque. It comes in blue, green, or brown, and his family chose brown for him,” said Dr. Price.
It was all part of a clinical trial involving 112 people who received artificial irises. Dr. Price has performed nearly half of those procedures. He expects Michael to heal quickly and he hopes the implants eventually get federal approval for wider use.
“I think it’s a tremendous asset for these people who have these conditions. It’s just phenomenal. Now, not everybody has a dramatic response but most of the people have a really dramatic improvement,” said Dr. Price.