From Darkness to Light: Giving Sight to the Blind
WebMD News Archive
Oct. 6, 2000 -- Science fiction is becoming less fiction and more fact every day. It is highly possible that in the not-too-distant future, medical science and technology will enable paralyzed people to walk, deaf people to hear, and blind people to see.
For Letitia Dobosy, the innovations can't come soon enough. When she was 29, she sensed something was wrong. "There was suddenly this imbalance in my eyes," she tells WebMD. "I was seeing differently out of each eye."
Her diagnosis: retinitis pigmentosa, a disease that slowly destroys the rods and cones within the eye's retina -- the light-sensitive cells in the back of the eye that make sight possible. In the U.S., retinitis pigmentosa is the leading cause of blindness in young people. That was 15 years ago, and doctors told her she would be blind by now. "But I'm not there yet," she says.
Still, Dobosy's interaction with the world has gradually altered as her eyesight has diminished. She can still read regular-sized print but has in recent years faced some limitations. "I gave up driving two years ago," she says. "I used to sew my own clothes ... I'm starting to have issues with mobility especially in unfamiliar territory ... problems with depth perception."
Dobosy says she has tunnel vision. But at present, medicine offers no means to reverse her progressively debilitating condition -- the key phrase being "at present."
While Dobosy's diagnosis is shared by millions, so too is macular degeneration, a cause of blindness that affects children and adults over age 60. "They are unable to read or drive or recognize faces -- or do anything that requires keen vision. They lose their independence because they can't drive, so they can't get from place to place, do their own shopping," says Philip Hessburg, MD, president of the Detroit Institute of Ophthalmology.
They are typically healthy people who find their independence and their lives limited forever by something entirely out of their control. "Once someone has lost all their vision, the options are to learn Braille, to have a reader, or to obtain a leader dog," says Hessburg.
Blindness -- once relatively ignored by research scientists -- has in recent years received greater attention and increased funding, all driven by expectations of increasing numbers of cases of blindness in an aging population.
Around the world, "bionic eyes" are under development.
Last summer, Hessburg headed an international symposium that brought together 20 of the world's leading researchers working on these inventions. The majority, he tells WebMD, are focused on developing intraocular retinal implants -- small microprocessor chips embedded in the eye, which send a message through the optic nerve to the brain.
One group of researchers at the Wilmer Eye Institute at Johns Hopkins Medical Center in Baltimore has paired a tiny television camera with something called an ultrasonic distance sensor (mounted on a pair of eyeglasses). The glasses send the signal to the sensor, which sends a signal to a microcomputer chip embedded on top of the retina -- which transmits signals to the brain's visual cortex, the area of the brain that controls vision, explains Giflin Dagnelie, PhD, assistant professor of ophthalmology at John Hopkins Medical School in Baltimore.