The last time she took to an Edinburgh stage, Candia McWilliam was wearing dark glasses and carrying a white cane. Yesterday at the closing event of the city’s International Book Festival, she took to the platform unaided, to celebrate the most remarkable of personal transformations — the return of her sight, achieved, as she said, “by the power of words”.

For much of the past three years McWilliam, 54, whose novel Debatable Land won the Guardian fiction prize in 1994, has lived as a virtual recluse, “a parrot in a cage with the hood over it”, because she had no wish to burden her friends and family with her blindness, brought on by a rare condition called blepharospasm.

She has stumbled around her own home, “an unpractised, blind, big person” breaking her leg in a fall down the stairs, and alarming her family so much that they insisted she could no longer live alone.

Then, in May last year, she was commissioned to write an article about her blindness for the Scottish Review of Books. A fellow sufferer of blepharospasm, who had been successfully treated, read the piece, and wrote to her recommending a surgeon who had developed a technique to tackle the condition. Little more than a year later, McWilliam, to her evident delight, can see again.

“Language is saturated with vision People say, ‘I see, I see’. It’s extraordinary. I haven’t caught up with being sighted, because I am so used to being unsighted,” she said. “Had that piece not been in the paper, she would not have written to me. It really does show this human generosity. My hope is that someone, in a similarly difficult situation, might read this.”

Blepharospasm, which may be caused by a malfunction in the brain, is a condition that causes the lids to close over otherwise healthy eyes. In the most acute cases, like McWilliam’s, it causes functional blindness and from the first diagnosis she visited more than 20 doctors, but none came close to restoring her vision.

McWilliam was working as a Booker Prize judge in 2006 when her condition first appeared, a juxtaposition which led to an initial diagnosis of exhaustion. She knew that this was not true: “I had always read exactly that much. A punishment for reading really does seem too atrocious an idea.”

McWilliam’s fate, it seemed was to have an “unwelcome resident” in her head for ever. “The more you fight, the more your eyes won’t open. It is a cunning, baffling, powerful adversary,” she said. Because her eyes functioned normally behind her eyelids, McWilliam had a consciousness of light and dark, “which I came to relish”. Occasionally, she said, “I would get moments of sight after rest, after a happy dream or after crying. Unfortunately, I am rather self-trained not to cry, I am trained to soldier on”.

Her lowest point came when a drug treatment failed. “A paper had been written saying that very high doses of prescription drugs could occasionally cause relief. In my case it didn’t,” McWilliam said.

“I was so intensively medicated that I had a grand mal fit, an extreme fit, a neurological crisis. I fell to the ground, I have no recall of it. I lost a day through a drug overdose.”

She awoke in a “dying ward” of a large London hospital. Ever since she had lost her sight, McWilliam added, people had asked whether her other senses had compensated. In that hospital, she was all too aware of the world around.

“My sense of smell worked very well. And my hearing had always been very acute — people were crying to be released from life. It was sad. I knew I was further from the end than that,” McWilliam said.

Her life has been transformed by Alexander Foss, a surgeon at Nottingham University, who has carried out his two-part treatment for blepharospasm just 15 times. He described it yesterday as a “route-one treatment” that first removes the muscle that makes the eye close, before a second intervention ensures that the patient’s brow remains suspended.

McWilliam underwent her first round of surgery in January. It was, she concedes, a touch macabre, “it sort of toughened up my eyelids, by stripping them out”. Then, in June, tendons from her legs were stitched into her eyes, effectively to pull them open, and keep them that way. She awoke to the mundane sights of a hospital ward. Her vision had returned.

McWilliam must have Botox treatment every three months for the rest of her life, to maintain her sight. She can close her eyes, but not in the conventional way. “I have to bring the lower part of my face up to meet my eyelids,” she said.

Other sufferers have to wear masks when they go to sleep, but McWilliam is lucky, she can close her eyes at night. Better still, by day, “I can talk to you, looking into your face, which I couldn’t do. The eyes speak. Without eyes I was denied a means of communication. Eyes are deeply empathetic things.”

McWilliam says she is now “tidying up a memoir” and has two novels in her head. After those, how her blindness plays out in her writing remains to be seen.

“Insofar as blindness has any gifts to offer, it offers a new way of seeing,” McWilliam said. “I can either use it to deplete my life or to add another layer. I would suggest I should do the second. I want to report from that other country.”

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