A New Corneal Implant Looks Promising


Once people start hitting middle-age, their eye-sight—especially their ability to focus on objects close to them—can begin to deteriorate. However, a corneal implant, called KAMRA, could assist people suffering from farsightedness.

The inability to focus on nearby objects is called presbyopia. Presbyopia occurs when the lens of an eye becomes harder and stiffer. This makes it more difficult for the surrounding muscles to squeeze into focus. One in five Americans suffer from presbyopia, and are forced to wear reading glasses.

Previously, the surgical option to correct vision problems was the LASIK surgery. LASIK, which stands for laser-assisted in situ keratomileusis, is used to correct nearsightedness, farsightedness, and astigmatism. During this procedure, surgeons create a flap in the cornea that can fold back, making it possible for them to remove part of the exposed cornea with a laser. Usually the procedure has a high success rate, however, there are numerous cases where LASIK surgery merely lowers the prescription—or worse—causes infection or night glare. This vision correction also tends to decrease in effectiveness as a patient ages, due to developing presbyopia.

While the LASIK surgery has been popular for years, a newer, less-invasive technique is gaining more recognition in the United States. It has been widely used around Europe, Asia, and South America. This technique is the KAMRA procedure. The surgery involves creating a small incision at the front of the cornea and implanting a doughnut-shaped ring that fits flexibly around the eye-lens. This ring takes over the role of the pupil.

Despite its popularity abroad, the United States FDA (Food and Drug Administration) advisory panel is not convinced that the KAMRA procedure is completely safe. The FDA conducted a 36-month trial that produced results from 478 patients. Eighty-three percent of the 478 participants gained 20/40 vision or better after receiving the KAMRA surgery.

However, this data did not include the results for 44 participants who exited the trial. About 86.4 percent of the patients that dropped out claimed the inlay did not improve their eye-sight. After these patients had their inlays removed, some individuals suffered from fluid build-up in their cornea and blurred vision. If the data from these patients had been included in the overall results, the percentage of successful inlays would have dropped to 75.8 percent.

The FDA is unsure of whether to approve the KAMRA procedure. While the FDA advisory panel voted seven-to-one in favor of the inlay’s effectiveness, the panel voted four to five against it for safety. One of the main reasons for the panel’s stance on the inlay’s safety is the large number of vision problems occurring after its removal.

“This is the windshield of the eye, and the windshield of the eye needs to be crystal clear like your car windshield,” said ophthalmologist, Dr. Anne Sumers. “If there’s haze or fluid in it, it’s not crystal clear,” she added.

Despite the apparent risks of the KAMRA surgery, with further experimentation and development, it may become a useful option for people suffering from presbyopia in the future.

[Sources: NPR; AllAboutVision.com]

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