Implantable
Miniature Telescope could enhance eyesight for 11 million Americans with
age-related macular degeneration
Seeing
Is Believing: Hope for the Blind
New
treatments, microchips and electronic implants show promise for millions with
impaired vision
By
Brad Stone
NEWSWEEK
May
19— Paul
Ladis can’t see his three daughters or his wife of 15 years, Beth. The former
machinist from Roselle, Ill., has been legally blind for a decade. He was born with a
hereditary disease called retinitis pigmentosa, a gradual decaying of the retina which
affects 100,000 Americans and can lead to total blindness. Last
year Ladis's brother told him of a company called Optobionics whose doctors were
implanting the first artificial retinas. Ladis, 45, applied to be a test subject and,
a few months later, walked into the Rush-Presbyterian-St. Luke’s Medical Center in
Chicago.
Today, a silicon chip two millimeters
across sits in his eye, converting light into electrical signals that travel through
the optic nerve to his brain. The technology is still in its infancy and offers no
hope of a total cure. But Ladis says he now notices shapes, lights and motion instead
of an inky gray darkness, and can function better around the house. “If I want to
reach out and hug my kids, I can see them walking by me now,” he says happily.
Ten years ago, the idea of placing a tiny
electronic device into the human eye seemed more suited to sci-fi than reality.
Compared with the ear, where cochlear implants have been effectively converting sound
into electrical impulses since the mid-’80s, the eye is a more sensitive and complex
piece of human anatomy. But today, a dozen teams of scientists around the world are
pursuing the goal of artificial eyesight for those who spend their days in darkness.
They’re proving that such technology is safe, and that it can improve the quality of
life for the vision-impaired. Like Paul Ladis’s bionic implant, the new devices do
not cure ocular disease, and none are approved by the FDA for general use. Yet early
promising results have spurred cautious optimism among ophthalmologists that the age
of combating blindness has finally begun. “The concept is no longer laughable,”
says Gerald Chader, the chief scientist for the advocacy group Foundation Fighting
Blindness. “There are patients living with implants that seem to work.”
The most prevalent disease researchers are
targeting is macular degeneration. The affliction, which affects an estimated 11
million (mostly elderly) Americans, leaves a foggy black splotch at the center of the
field of vision. Patients often must use huge closed-circuit TVs to magnify newspapers
or books, or big, unwieldy head-mounted telescopes.
The Saratoga, Calif. based VisionCare wants
to lighten their load. The
IMT (Implantable Miniature Telescope) evolved out of Israeli research into
optics and is roughly the size of a pea. Inserted into one eye like the intraocular
lens in cataract surgery, it projects a magnified image over a wide field of the
retina. After an hour long procedure, patients must undergo extensive training to
learn to use the implanted telescope for central vision and the other untreated eye
for mobility and peripheral vision. The device, now in FDA trials, has been implanted
in more than 70 patients, and VisionCare scientists are very optimistic about early
results.
“For an 80-year-old to sit and watch TV or read headlines in a newspaper or pay
their bills, it’s a godsend,” says Robert M. Kershner, MD a Tucson ophthalmologist
involved in the trials.
(Dr. Kershner Performs the IMT
Surgery)
The IMT only augments
eyesight in those with damaged retinas. Artificial implants that
replace retinas, like the kind Paul Ladis received, are farther
behind. Brothers Alan and Vincent Chow of Optobionics have implanted
their microchips in 10 patients. The chips aren’t actively powered;
each contains 5,000 solar cells that convert light into electric
impulses that stimulate weakened cells in the retina. Optobionics
patients, Alan Chow says, are reporting “moderate to substantial
improvement in vision.” One patient, blind for decades, remarked
to doctors that modern automobiles look ugly. Researchers
at the Doheny Retina Institute at the University of Southern California
are exploring a variation of the same idea. In the Doheny system,
a camera on the patient’s eyeglasses captures and transmits images
to an implant. Patients also wear a battery pack that transmits
power magnetically to a receptor behind the ear, which then sends
electricity to the implant to stimulate nerve cells. Chader, of
the Foundation Fighting Blindness, says he witnessed an evaluation
of one of the Doheny Institute’s three test patients: the man,
blind for 30 years, was able to make out two of the big letters
on the eye chart.
Perhaps the most exciting
aspect of all these devices is that they should get better quickly,
now that medical researchers have hitched their wagon to ongoing
improvements in microchips and miniaturization. For example, the
Doheny chips currently include 16 electrodes, but professors there
talk of next-generation implants that could include up to 100.
Scientists at VisionCare theorize about one day allowing patients
to control their implanted telescopes, zooming and changing focus
like “The Six Million Dollar Man.” The technology will take years
to develop, but until gene researchers can locate and replace
the chromosomes responsible for ocular disease, the devices will
offer the best hope for the severely vision-impaired. Paul Ladis,
for one, is enthusiastic. “I would love to see my kids’ faces,”
he says. “I would love to read books to them. That would be fantastic.”