May 4, 2012
Two Blind Men Receive Some Sight Through Eye Implants
Two blind men have received sight for the first time in years due to new advances in medical science.
A 0.12-inch square microelectronic chip with 1,500 light-sensitive pixels was surgically implanted behind the retina, where a cable runs to a control unit under the skin behind the ear.
When light enters the eye and reaches the chip, it stimulates the pixels, which sends electronic signals to the optic nerve and from there to the brain.
The chip can have its sensitivity changed through an external power unit, which is connected to the chip on a magnetic disc on the scalp.
James said there was a moment when the implant was switched on for the first time, and he saw flashing lights.
"I am able to make out a curve or a straight line close-up but I find things at distance more difficult," James told BBC News. "It is still early days as I have to learn to interpret the signals being sent to my brain from the chip."
He said he eventually wants to be able to make out the silhouettes of different cars on the race track.
Professor Robert MacLaren, which lead the trial along with Tim Jackson, said this is the first time a patient went from being completely blind to seeing something.
"In previous studies of restorative vision involving stem cells and other treatments, patients always had some residual sight," he told BBC. "Here the patients had no light perception at all but the implant reactivated their retina after more than a decade."
Millar says that he is now able to dream in color for the first time in 25 years, and is able to stand in a room and detect light coming through windows.
MacLaren said the results may not seem extraordinary, but for a blind person to be able to orientate themselves in a room could be of practical help.
Jackson, eye surgeon at King's College Hospital, warned that the treatment is still at its early stage of development, but said "it is an important and exciting step forward, and may ultimately lead to a much improved quality of life for people who have lost their sight from retinitis pigmentosa."
"Most of the people who receive this treatment have lost their vision for many years, if not decades," he told BBC. "The impact of them seeing again, even if it is not normal vision, can be profound, and at times quite moving."
During the clinical trial, up to a dozen British patients will be fitted with the implants. Patients with glaucoma or optic nerve disease are not eligible for the study at this time.