Douglas Waters, 86, and an unnamed woman in her early 60s were suffering from age-related macular degeneration.
It is a condition that leads to a rapid loss of central vision and affects more than 600,000 people in Britain.
But after undergoing the ground-breaking clinical trial – where each received a new stem cell-based treatment during an hour-long operation – they were amazed by the staggering results.
Mr Waters, from Croydon, south London, who developed the condition in his right eye three years ago, said: “In the months before the operation my sight was really poor and I couldn’t see anything out of my right eye. I was struggling to see things clearly, even when up close.
“After the surgery my eyesight improved to the point where I can now read the newspaper and help my wife out with the gardening.
“It’s brilliant what the team has done and I feel so lucky to have been given my sight back.”
The treatment saw cells from a human embryo grown into a patch in a laboratory before being delicately inserted into the back of the eye.
Last night, the scientists behind the treatment, which they compared to “laying a new carpet”, said they hoped the breakthrough could lead to an “off-theshelf” treatment within five years.
Professor Lyndon da Cruz, consultant ophthalmologist at Moorfields Eye Hospital NHS Foundation Trust in London, said: “We’ve restored vision where there was none.
“It’s incredibly exciting. 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 in the eye and get vision back.”
He added: “The results suggest that this new therapeutic approach is safe and provides good visual outcomes. The patients who received the treatment had very severe AMD, and their improved vision will go some way to enhancing their quality of life.
“We recognise that this is a small group of patients, but we hope that what we have learned from this study will benefit many more in the future.”
Age-related macular degeneration is the leading cause of blindness in the UK and the third globally.
Both patients in the trial had “wet” age-related macular degeneration.
This form of the disease is caused by abnormal blood vessels growing through the retinal pigment epithelium and damaging the macula.
Dry age-related macular degeneration is more common and caused by the retinal pigment epithelium breaking down. It is hoped the patch will be able to treat both forms.
Professor Pete Coffey, from the UCL Institute of Ophthalmology, said: “This study represents real progress in regenerative medicine and opens the door on new treatment options for people with age-related macular degeneration.”
The treatment marked the first time an engineered piece of tissue has been successfully used to treat people with sudden severe sight loss.
It saw researchers investigating whether the diseased cells at the back of the patients’ affected eyes could be replenished using a stem cell patch.
A specially engineered surgical tool was then used to insert the patch under the retina in the eye of each patient in an operation lasting between one to two hours.
It is hoped the length of this procedure will be shortened to around 45 minutes.
The patients – who went from not being able to read at all, even with glasses, to reading 60 to 80 words per minute with normal reading glasses – were monitored for 12 months before reporting major improvements in their vision.
The successful clinical trial was the result of a partnership between Moorfields Eye Hospital NHS Foundation Trust, the UCL Institute of Ophthalmology and the National Institute for Health Research.
The findings of the trial are published in the journal Nature Biotechnology.