COULD READING GLASSES SOON BE A THING OF THE PAST
A thin ring inserted
into the eye could soon offer a reading glasses-free remedy for presbyopia, the
blurriness in near vision experienced by many people over the age of 40,
according to a study released at AAO 2014, the 118th annual meeting of the
American Academy of Ophthalmology. A corneal inlay device currently undergoing
clinical review in the United States improved near vision well enough for 80
percent of the participating patients to read a newspaper without disturbing
far distance vision needed for daily activities like driving.
Presbyopia affects
more than 1 billion people worldwide.[1] As people age, the cornea becomes less
flexible and bends in such a way that it becomes difficult to see up close.
While the most common remedy is wearing reading glasses, a host of new corneal
inlay products are in development to treat the condition, with three types
currently under review by the U.S. Food and Drug Administration (FDA). The
theoretical advantage of using corneal inlays over wearing reading glasses is
that corneal inlays prevent the need for constantly putting on and taking off
glasses, depending on whether the person needs to see near or far.
One of the devices is
the KAMRA inlay, a thin, flexible doughnut-shaped ring that measures 3.8
millimeters in diameter, with a 1.6 millimeter hole in the middle. When dropped
into a small pocket in the cornea covering the front of the eye, the device
acts like a camera aperture, adjusting the depth of field so that the viewer
can see near and far. The procedure to insert the implant is relatively quick,
lasting about 10 minutes, and requires only topical anesthesia.
To test the inlay's
efficacy, clinicians conducted a prospective non-randomized study of 507
patients between 45 and 60 years of age across the United States, Europe and
Asia with presbyopia who were not nearsighted. The researchers implanted the
ring in the patients and followed up with them over the course of three years.
In 83 percent of eyes with the implant, the KAMRA corneal inlay allowed
presbyopic patients to see with 20/40 vision or better over the three years.
This is considered the standard for being able to read a newspaper or drive a
vehicle without corrective lenses. On average, patients gained 2.9 lines on a
reading chart. The researchers report that the results remained steady over a three-year
period.
Complications from
corneal inlays in general have included haziness that is treatable with
steroids; however, improvements in inlay design have made the effect less
common. If necessary, inlays can be removed, making it a reversible treatment,
unlike other procedures such as LASIK for presbyopia.
"This is a
solution that truly delivers near vision that transitions smoothly to far
distance vision," said John Vukich, M.D., author of the poster and a
clinical adjunct professor in ophthalmology and vision sciences at the
University of Wisconsin, Madison. "Corneal inlays represent a great
opportunity to improve vision with a safety net of removability."
The device is sold in
regions including Asia, Europe and South America, but is not yet approved by
the FDA for use in the United States. There are two other types of corneal
inlays, Raindrop Near Vision Inlay and Presbia Flexivue Microlens, also in
development for the U.S. market.
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