British prime minister Gordon Brown would have gone almost blind but for a surgical intervention by an Indian doctor 38 years ago.

According to a report in The Times on Monday, after four decades as a barely acknowledged footnote in Brown's career, Dr Hector Chawla has spoken at length, for the first time, about the procedure that saved the future prime minister's sight.

Dr Chawla, who was born in Sialkot in pre-partition India to a Scottish mother and an Indian father serving in the British army during World War II, said, "The story in most of the biographies is that he had four operations, which left him with partial sight in one eye."

"That's not true. He had three operations that left him blind in one eye and one operation that I performed that restored his vision completely (in the other eye). And nearly 40 years later he's still got perfect sight in that eye." Dr Chawla, now 70, said.

When the teenage Gordon Brown, then a student at Edinburgh University with a growing reputation as a left-wing radical, was referred to Dr Chawla in 1970, he had already gone blind in his left eye.

During a rugby match several years earlier, he had gone down on a loose ball and been kicked in the head close to his eyes.

Within weeks he had started to notice a shadow across the vision in his left eye and the diagnosis was a detached retina - the membrane that lines the inside of the eye and converts light into nerve signals that are transmitted to the brain.

Despite three operations, after which he spent weeks lying in a darkened room with patches over his eye, the attempts to repair the damage failed. The techniques used during the surgery were not precise enough to locate the tear in the retina, Chawla said.

When similar symptoms began to affect his right eye, the young Brown feared that it would only be a matter of time before he went blind.

With his sight gradually failing, he was referred to the young Dr Chawla, who had just returned from a year-long fellowship as a retinal surgeon in Chicago.

He was a senior registrar at Edinburgh Royal Infirmary and one of a tiny number of surgeons in Britain who were trained in pioneering techniques that allowed the whole of the retina to be seen during surgery.

Dr Chawla said that he just happened to be in the right place at the right time and that without him Brown would have gone blind. "He would  have had no light perception in either eye. His life would have been completely different," he said.

Although Dr Chawla has little recollection of his most famous patient, he does remember Brown's father. "His father gave me a book token and said how grateful he was. I think it was for about five or ten pounds, which was a lot of money back then".

Dr Chawla, a precise, fastidious man who went on to set up Scotland's first centre of retinal surgery, said that he occasionally glimpsed the long-haired Brown during his days as the firebrand student rector of Edinburgh University, but had no contact with him until the late 1980s.

"My wife and I were on a train and he was sitting there working away. I introduced myself and I think he was quite taken aback. He then had us down to the Commons and arranged for us to go out to dinner, and when I went to pay the bill he'd already paid it," he said.

He still exchanges Christmas cards with Brown, and occasional notes and e-mails.

In September, in his first speech to the Labour Party conference, as leader, Brown spoke about 'the skills of a surgeon' who restored his sight, but did not mention Dr Chawla by name.

Brown said, "From the age of 16 to 21, I spent a lot of time in hospital as the National Health Service worked to save my sight. It was the skills of a surgeon, the care of wonderful nurses, the attention and, yes the love and care of the NHS staff that managed to save one of my eyes. And it is because of the NHS that I can see the words I read today".

Although Dr Chawla knows that the prime minister is grateful, he said that he would like some public recognition for the work he performed on his most famous patient.

"That operation changed his life and no doubt all our lives," he said. "Do I feel a little sad that it hasn't been recognised? I suppose the answer is yes, I do. I just feel that things have slipped by a little bit without recognition. It sounds pompous to say but I suppose, step by step, I have become aware that I have been involved with a bit of history".