SCIENCE VISIONARIES EXPERIMENTAL RETINAL IMPLANTS COULD RESTORE SIGHT TO THE BLIND.

Byline: Robert Monroe Staff Writer

ANTA CLARITA - Encroaching on the domain of miracles, a biotechnology firm hopes to restore long-term vision to blind people as early as next year.

The name of the company, Second Sight, extends a promise made when the first blind patients reported - with a mix of elation and confusion - seeing basic shapes during university experiments nine years ago.

Now the company joins a small field of competitors racing to be the first to create replacements for damaged retinas that are suitable for widespread use. Second Sight President Dr. Robert Greenberg said such use of his implant is a ``when'' rather than an ``if'' proposition now that a key threshold - wireless transmission of images to the retina - appears to have been crossed.

``What we'd like to be able to do is send patients home with these devices,'' Greenberg said.

If key problems are solved, researchers estimate that implants could be available to the general public within a decade. The potential market for Second Sight's retinal implant, which works on the same basic principle as a television, could number as high as 20 million, the estimate of how many people worldwide have degenerative retinal diseases.

Dr. Gerald Loeb, director of the Medical Devices Development Facility at the University of Southern California, thinks Second Sight and its collaborators stand the best chance of success among research groups attempting retinal implants. The size of the eye and its delicacy, however, makes Loeb think that implants directly onto the brain's visual cortex - also under research - stand a better chance.

Then again, Loeb said, people said cochlear implants would never help deaf people hear, an successful invention he helped create 20 years ago.

``If you're going into the eye, the way they're doing it is the right way in my opinion,'' he said.

Even though the artificial sight might never become as good as the real thing, some of the 20-odd people who have had basic sight restored for mere hours have signed up to be experiment subjects again and again.

Harold Churchey, a 72-year-old Sharpsburg, Md., resident has undergone three implant surgeries since 1992. Retintis pigmentosa has stolen all of what little sight he had to begin with as a child.

``About the only way I know the sun is shining is I feel the heat,'' said Churchey, who ran a snack bar in a state physical rehabilitation center for 33 years before retiring in 1996.

In the first experiment, he saw a burst of light. In the third surgery, four years later at Johns Hopkins University, he was able to make out the letter H after electrodes in that shape were stimulated. He called the experience a blessing and said if researchers want him for a fourth try, he's ready to go.

``I have a routine but I'd be happy to change that routine if I could see,'' he said.

Retinal disease foundations are as excited as Churchey. Tom Hoglund, spokesman for the Foundation Fighting Blindness in suburban Baltimore, said implants' potential to at least allow people to function without seeing-eye dogs is ``in itself just fantastic.''

``We've been watching this field grow immeasurably,'' Hoglund said. ``There's clearly commercial interest in developing this and when there is, that shows that somebody believes there is a viable product out there.''

Mann aboard In the case of 18-month-old Second Sight, the commercial interest has come from local high-tech inventor and financier Al Mann, whose other ventures include insulin pump maker MiniMed and cochlear implant maker Advanced Bionics. Mann leads a trio of investors interested in commercial results.

``Universities don't always have the same objectives, the same methods,'' he said. ``They don't really know how to make products.''

Eye researchers have pursued artificial vision through devices like Second Sight's for 20 years, borrowing ideas from the first cochlear implants that restored hearing in deaf patients. The eye implant Greenberg envisions would include a camera mounted on a pair of glasses. It would break down images like pixels on a television screen and transmit them to a panel of electrodes positioned over the retina.

To date, human recipients have had a power source attached to an electrode array by a wire that protrudes from the sclera, or white of the eye. The exposed wire would make the device too hazardous for everyday use. And the best resolution researchers have been able to produce allowed patients to distinguish letters on stark backgrounds like Churchey's H, but no more.

So far, researchers have made an electrode panel that produces a mere 25 pixels of sight, compared with about 300,000 that make up images on a basic computer screen. Imagine everything in your field of view limited to 25 blocks, each filled with a blob of a single color.

Shadow of Magic Mountain Regardless of the slow process, problems that might have taken several decades to solve have already been overcome. Greenberg credits an infusion of cash by Mann and other investors for the creation of a new prototype - one without dangerous wires protruding through the eye.

The company, situated in an anonymous business park in the shadow of Magic Mountain, joins at least three other research groups in the United States and Germany attempting to make various implants work. There is a faint atmosphere of espionage as players try to guess if there are still more competitors and closely guard data about their own products.

Greenberg covered up chalkboards full of calculations as he talked to a reporter in his office last week. He would not say when exactly the wireless implant was developed, but it was sometime this year and has been fitted in an animal. The device transmits the signal via radio waves, the glasses-mounted camera being the television station beaming images to the TV set that is the implant.

The device's safety is tested first, then its effectiveness. A clinical trial for humans would be next.

Best and brightest It's in the nature of experiments to have downsides and the implants are no exception.

Early on, researchers decided that people who have never had sight before do not make the best candidates. Greenberg recounts the story of an early experiment, in which an implant recipient was disturbed by the strange bursts which his brain had never had reason to comprehend before.

``It was as if he had ESP,'' Greenberg said.

And there are several problems to be resolved before the previously sighted can have some vision restored. Greenberg hopes to be able to make a 33-by-33-electrode array so recipients can improve resolution but the means must be found to fit more electrodes on the same 2-by-3 millimeter panel.

Beyond that, implant chips, being electronic, could pose a hazard to surrounding eye tissue by the heat they produce. They also need a place in the inner eye on which to anchor. Greenberg, whose company announced a formal research collaboration with five universities at the end of June, has yet to figure out how to keep it from floating around in the fluid-filled center of the eye.

But Greenberg said a study not yet published will show that the heat generated is not sufficient to cause damage and that the collaboration is exploring methods such as tacking the implant onto the surface of the retina.

``We've assembled the best and brightest minds to work on these problems,'' Greenberg said. ``There are thousands of patients who have no hope of vision by any other means.''

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Photo: (1 -- color) Dr. Robert Greenberg is president of Second Sight, a Santa Clarita retinal implant company. (2 -- color) Second Sight's prototype implants, smaller than a thumbnail, is designed to replace damaged retinas and repair sight by transmitting images to the brain. Hans Gutknecht/Staff Photographer