He told BBC News: “A genetic treatment administered early on to preserve vision in patients who would otherwise lose their sight would be a tremendous breakthrough in ophthalmology and certainly something I hope to see in the near future.”

Mrs Osborne, 80, is the first of 10 patients with AMD taking part in a trial of the gene therapy treatment, manufactured by Gyroscope Therapeutics, funded by Syncona, the Wellcome Trust founded investment firm.

What is AMD?

The macula is part of the retina and responsible for central vision and fine detail.

In age-related macular degeneration, the retinal cells die and are not renewed.

The risk of getting AMD increases with age.

Most of those affected, including all those on this trial, have what is known as dry AMD, where the decline in sight is gradual and can take many years.

Wet AMD can develop suddenly and lead to rapid vision loss but can be treated if caught quickly.