Seeing clearly with an iris implant

October 4, 2010 3:56:11 PM PDT
Every year, 2.5 million people suffer some kind of eye injury. More than 50 percent of those injuries happen before age 25. If the iris, or the color part of your eye, is damaged, it can lead to a lifetime of double vision, blurriness and in rare cases, blindness. Now, a new kind of prosthesis is helping eye injury patients who have run out of options.

It's construction manager Don Davis's job to focus on the details. But for the past 30 years, that's been difficult. He's missing part of his right eye, damaged by a direct hit from a racquetball.

"One of the things that happened during the trauma was that I lost my iris," Davis said. "My iris drew back, and my eye was one large, black pupil."

"The iris is what makes the pupil smaller or larger, so it acts like the shutter for the eye," Amit Chokshi, M.D., an ophthalmologist at Baptist Medical Center in Jacksonville, Fla., explained.

Everything Davis saw had a glare, halo around it, or he saw double. Sunglasses and colored contact lenses weren't enough.

"If you can imagine someone taking a flashlight and turning it on and just sticking it in your eye and you get kind of sensitive, it was that, all the time," Davis recalled.

Doctors suggested an artificial iris.

"It's about nine millimeters in width, and only four millimeters actually allows light to get in, so less than 50 percent of the device lets light in," Dr. Chokshi said.

This prosthetic iris is custom color-matched to the patient's healthy eye. In surgery, it's implanted through a nine-millimeter incision between the white of the eye and the cornea. In Don's case, a lens was added to help improve his vision.

"The sun is much better, as you can imagine," Davis said. "It's not nearly as blinding as it was."

With the iris implant providing an extra layer of protection, Davis is seeing his world in a whole new light.

The artificial iris is still investigational, but more than 100 people have received the implants under a compassionate use FDA trial. Studies are near completion, but the device has not received FDA approval.

Patients who benefit from the artificial iris fall into two main categories: people who were born without an iris and those whose iris is damaged or destroyed in some sort of traumatic injury.

This experimental iris implant is only done for therapeutic purposes. Once it's in, doctors say it can last a lifetime.


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