There’s new hope for those who have an eye disease that leads to blindness. As physicians reported on Wednesday, an experimental gene therapy for blind patients improved their vision, stopped the deterioration of their sight and even reversed some of the vision damage.
In a study that was supposed to test only the safety of the gene therapy, doctors were surprised to find that such therapy ended up improving the vision in patients with a blinding disease. Moreover, the improvements continued for two years in one patient.
British researchers wrote about their findings in the Lancet medical journal, although lead researcher, Dr. Robert MacLaren of the Nuffield Laboratory of Ophthalmology at the University of Oxford, said that it’s still too soon to know if the gene therapy will provide lasting results.
However, Dr. MacLaren noted that improvements in patients' vision have lasted for as long as his research team has been following up on those treated with the gene therapy, including a patient whose sight has continued to get better for two years.
“In truth, we did not expect to see such dramatic improvements in visual acuity, and so we contacted both patients’ home opticians to get current and historical data on their vision in former years, long before the gene therapy trial started. These readings confirmed exactly what we had seen,” MacLaren added in a statement.
In the meantime, gene therapy isn’t always an effective treatment. Not only can it be difficult to deliver new genes into a patient’s body, but it’s also uncertain whether the cells of a patient will accept the new gene; thus, enabling the body to use it.
However, it can be easier to deliver new genes into the eye than into other body parts, as the eye allows doctors to see the results of treatment in real time. Additionally, treating just one eye allows them to compare the results to the other eye that was not treated.
“This has huge implications for anyone with a genetic retinal disease such as age-related macular degeneration or retinitis pigmentosa, because it has for the first time shown that gene therapy can be applied safely before the onset of vision loss,” MacLaren said.
So far, MacLaren says that nine patients in different stages of vision loss have been treated with gene therapy in one eye at Oxford Eye Hospital in the UK.
“If we were able to treat people early, get them in their teens or late childhood, we’d be getting the virus in before their vision is lost,” he said. “If the treatment works, we would be able to prevent them from going blind.”