The two patients, a man and a woman, had advanced age-related macular degeneration (or AMD), a problem that destroys the central vision. Before the procedure, neither was able to even see a book, according to their surgeon. After the procedure, their sight has improved dramatically.
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"The first patient has got six lines improvement, which is astounding, and the second has five lines and he seems to be getting better as the months go by. They are both really reading," Pete Coffey of the University College London, one of the scientists behind the medical breakthrough, told The Guardian. "At best [the woman] could read about one word a minute with magnification. She is now reading 80 words a minute and [the man] is reading 50."
Coffey said that the results were even better than what he and his colleague, Lyndon Da Cruz, a retinal surgeon at Moorfields Eye Hospital, initially hoped for.
"We said we'd get three [out of the proposed 10] patients with vision recovery of three lines. They probably wouldn't get reading vision back," he said.
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"In the months before the operation my sight was really poor and I couldn't see anything out of my right eye," 86-year-old Douglas Waters, a patient involved in the study, told the BBC. "It's brilliant what the team have done and I feel so lucky to have been given my sight back."
According to the Foundation Fighting Blindness, AMD is the most common cause of blindness in developed countries. Across the United States, more than 10 million people suffer from the disease. Individuals with AMD experience loss of vision due to the death of a thin layer of light-sensing retinal cells at the back of the eye, located in a region called the macular.
The individuals involved in this trial had a severe form of the disease referred to as "wet" AMD. This can cause sight loss to occur rapidly, often within a matter of days or weeks.
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"What's exciting about this study is that the patients recorded an increase in vision. Patients with very poor vision are chosen for phase 1 trials because of their 'untested' nature," Dr. Carmel Toomes, associate professor at the Leeds Institutes of Molecular Medicine, who was not involved in the research, told The Independent. "To see an improvement is a good sign that this therapy may help patients in the future, although further studies are needed before real conclusions can be drawn."
"We've restored vision where there was none," Da Cruz said. "As you get older, parts of you stop working and for the first time we've been able to take a cell and make it into a specific part of the eye that's failing and put it back in the eye and get vision back."
The researchers hope their trials will lead to an affordable 'off-the-shelf' therapy within as little as five years.
As for the patients involved with the trial, they're just grateful to see again. "I can now read the newspaper and help my wife out with the gardening," Waters said.
Read the full study at nature.com.