Julie Hearn, 46, is one of the brightest new stars in the now star-studded world of children’s fiction. Her first novel, Follow Me Down, published two years ago, was nominated for two highly prestigious awards, the Carnegie Medal and the Branford Boase Award, and received enthusiastic reviews — not least from Philip Pullman, the author of His Dark Materials, who taught her at teacher training college.

Her second book, The Merrybegot, promises even greater things. It has already been seized on by her US publisher as the lead children’s title for summer; no mean feat for a novel which tackles 17th-century witchcraft. The book, whose heroine is an apprentice village healer, grew out of Hearn’s interest in herbal remedies and alternative medicine — an interest she was able to satisfy while writing the novel. She spent six months researching traditional medicine in the Bodleian Library, Oxford, poring over Culpeper’s Complete Herbal and studying ancient Wiccan spells.

Ironically and sadly, her interest in complementary therapies has recently been thrown into sharp focus in her own life. Until three years ago, she had excellent sight. Then, like many fortysomethings, she went for a routine test to see if she needed reading glasses, which revealed a weakness in her left eye. She was referred to the local NHS eye hospital, where the consultant diagnosed severe congenital retinal degeneration, a genetic disorder. She wasn’t too worried because Hearn’s central vision, as opposed to peripheral, was unaffected but suggested that she saw another consultant who was researching the disease. Hearn declined: “I was too busy. I was naive really. I thought, it’s not affecting my central vision, so I didn’t worry about it. I just bought a pair of reading glasses, which helped, and carried on with my life.”

Last summer, however, she began to feel disorientated and noticed that she was knocking things over, even when taking care. Hoping that she might just need stronger glasses, she returned to the optician and was shocked to discover that she couldn’t read any letters on the chart with her left eye. At the hospital, tests showed the damage to this eye was irreversible and that there were traces of the disease in her right eye. Her condition is untreatable. But if she has any comfort, it is that her mother, who also developed the condition in her late forties, is now in her seventies and still has normal vision in her right eye.

The consultant suggested further tests to pinpoint the health of Hearn’s good eye more accurately and to determine the exact nature of the disorder. Before she agreed to the tests though, Hearn had two questions: “Is there any possibility of cancer?” (no) and “Can I still wear mascara?” (yes). Then just before Christmas she made the decision not to return. “I don’t see conventional medicine as the bad guy but if there is nothing the doctors can do, what’s the point of more tests? The staff are fantastic but I found the whole thing demoralising. I just wanted to get on with my life. I’ve always believed in an holistic approach to health, so I’m letting my mind and body do what seems to be the right thing.

“In the first week after the diagnosis I bought classical music, highly scented flowers and incense, and started cooking spicy food. It was instinctive; later somebody told me that stimulating the other senses was a positive holistic thing to do.”

Her consultant advised her to give up smoking, to wear special dark glasses in sunlight to protect her eyes from ultraviolet light and to eat plenty of brightly coloured vegetables, particularly those that are high in vitamin A and the antioxidant lutein, including peppers, kale, sweetcorn and bilberries.

A recent study by researchers at Ohio State University found that lutein, apart from helping to protect the central part of the retina from age-related deterioration, reduced damage in the cells of the eye lens from ultraviolet light.

As well as growing her own healing herbs — borage, lemon balm and feverfew, which are believed to promote eye health — Hearn buys only organic produce wherever possible. “Giving up smoking was surprisingly easy because I felt I was playing a part in my own healing process. I’m aware that these things may not make any difference to what is a genetically programmed process of degeneration. All I can do is what makes me feel better about the condition and enhances my quality of life.”

Above all, she is a firm believer in positive thinking, particularly as she is aware that there is a chance that her 15-year-old daughter Tilly may inherit the condition, too. She does acknowledge, however, that if her right eye deteriorates she will have to return to hospital. Unfortunately, magnification aids, if her sight becomes significantly worse, will be of little use as retinal deterioration affects central vision, causing distortion.

So far, the disease is manageable. Hearn has stopped driving at night and works for shorter stretches. She is practising writing chunks of her third novel in longhand because, with limited vision, it will be easier than trying to use a computer. Although there have been low points, Hearn, a single parent, has cried only once — when she phoned to cancel her hospital appointments. “The consultant’s secretary gave me the number of the genetic counsellor and said, ‘I don’t want you to be on your own with this’. I just welled up, put the phone down and had a good weep. I hadn’t realised I was so upset. You tread a fine line between not burying it so it becomes a big gremlin, but not letting it spoil your life.”

Julie Hearn’s new novel, The Merrybegot, is published this month by OUP, £5.99

Sharper focus

Macular Disease Society (www.maculardisease.org) or Moorfields Eye Hospital helpline (020-7566 2345)