At first, sitting in church one Sunday, Michael Adler couldn't tell what the whitish glow in front of him was.

Adler, 49, had been legally blind since childhood, and his vision eventually deteriorated to pretty much zero.

But now, on the back of the pew in front of him, he saw something. And then he realized: It was the pages of a hymnal. His new "eye" was starting to work.

Two months earlier at Wills Eye Institute, surgeons had implanted a small array of electrodes in the back of Adler's left eye - a speck of metal no bigger than the word eye on this page. In the last few weeks - with the aid of a small video camera in his sunglasses that transmits images to his retinal implant - he has begun to gain some limited vision.

"Every day, I can make out more than I could the day before," he said after a round of follow-up tests at the University of Pennsylvania. "It's very weird trying to get used to it."

Surgeons have implanted the devices in the retinas of 32 people around the world. All have a severe form of retinitis pigmentosa, an inherited disease that causes retinal degeneration.

Much like a cochlear implant enables a deaf person to perceive sound, the retinal implant bypasses damaged cells in the eye, transmitting signals to the same part of the brain that registers images in people with normal vision.

"It's sort of like, all the phone lines are in place and you didn't have the phone," said Julia Haller, ophthalmologist-in-chief at Wills. "This replaces the phone."

The resulting black-and-white images are very low-resolution, consisting of just 60 pixels - far too fuzzy for users to pick out letters on an eye chart. To Adler, a massage therapist who lives in Mantua, Gloucester County, the face of his 9-year-old daughter looks like a bright, featureless oval.

But he can see the outlines of doors and sidewalks, and he can pick out plates on the dinner table.

This type of surgery is just one of several futuristic techniques that scientists are exploring to help the blind, advances that until recently were only a dream.

In younger patients with another type of blindness, researchers have had some success with gene therapy, restoring a modest amount of vision by injecting corrective genes. Two such efforts are under way at Penn: one in collaboration with Children's Hospital of Philadelphia, the other with the University of Florida at Gainesville.

Elephant on a typewriter

Other methods under scrutiny include stem cells, which would regenerate the eye's rods and cones, and cortical implants, which are a bit like what Adler has in his eye, but which are placed directly in the brain, bypassing the eye.

"The progress is remarkable compared to what it was five years ago," said Andrew Mariani, a program director in the National Eye Institute's division of extramural research. "What it will be in another five or 10 years, we can just guess."

Along the way, scientists are starting to learn new things about the brain's plasticity - its ability to adapt.

In blind people, especially those who lose their sight at an early age, parts of the visual cortex are commonly borrowed to enhance other senses, said the University of Southern California's Mark S. Humayun, a leader of the retinal-implant project.

So a big question is, when some sight is restored, are those parts of the brain borrowed back? Humayun, a biomedical engineer and an ophthalmologist at the Doheny Eye Institute at USC, plans to use brain scans to answer that question.

Another puzzle is why people with the implants are able to see much of anything, because the implanted electrodes, though gossamer-thin, are still much thicker than the natural machinery they replace.

In the center of a healthy retina, the signal from each light-sensitive cone cell is transmitted to one ganglion cell, and ultimately through the optic nerve to the brain.