Professor Robert MacLaren, who led the gene therapy operations at Oxford Eye Hospital, said his team are "absolutely delighted" with the results so far.
It is still too early to know if the gene therapy treatment will last indefinitely, but we can say that the vision improvements have been maintained for as long as we have been following up the patients, which is two years in one case.
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 in our study and provided an independent verification.
Preliminary results from the first six patients taking part in a Phase One trial surprised the Oxford University team.