When Julie Hearn was diagnosed with a rare genetic condition that means she could go blind, she spurned conventional medicine for a diet of bilberries and kale

For Christmas I got a bilberry bush, a smoothie maker and a zip-up plastic greenhouse. I also quit smoking. Ordinarily, I would have asked for lots of chocolate, and carried on puffing. But last November I discovered that I am losing my sight. And a fag-free life, coupled with a steady diet of lutein-rich smoothies and home-grown greens appears to offer the best chance I have of saving it.

For Christmas I got a bilberry bush, a smoothie maker and a zip-up plastic greenhouse. I also quit smoking. Ordinarily, I would have asked for lots of chocolate, and carried on puffing. But last November I discovered that I am losing my sight. And a fag-free life, coupled with a steady diet of lutein-rich smoothies and home-grown greens appears to offer the best chance I have of saving it.

I have inherited a severe form of retinal degeneration - a progressive disease with no known cure. My mother has it, and my grandfather had it, too. If I close my right eye, the world looks like a Picasso painting. Faces slip, straight lines become distorted and letters and words fuse together. There are horrible things going on behind my pupils, which I'm glad cannot be seen by anyone except an ophthalmologist. We're talking wear and tear, mutation and cell damage. We're talking mess.

My mother, like her father before her, is still able to see, because her right eye has remained unaffected. Unfortunately for me, my own right eye has developed traces of the disease and, like a ticking time bomb, could go at any time. If and when that happens I would retain peripheral vision but driving and reading would become impossible, writing would be difficult, and getting around in a lopsided world, full of unrecognisable faces, would be a challenge to say the least.

At 46, I have led a charmed and healthy life and have plenty to be thankful for. This won't kill me - it isn't even painful. But the prospect of permanent sight loss is still terrifying, particularly as my sight is not only precious but essential for my work. I write historical fantasy for young adults. Weeks, sometimes months, are spent in libraries researching obscure and forgotten details of past lives and centuries. My first novel, Follow Me Down, was nominated for the prestigious Carnegie Medal. My second, The Merrybegot, has just been published. As a single parent, formerly on benefits, I came late to this career. And the prospect of being unable to read - to lay the foundations for future novels - makes me incredibly sad.

"So, what can be done?" I asked my consultant, fully expecting that something could. A bit of laser treatment, a course of steroids perhaps, and perfect sight would again be mine. I knew my mother hadn't been offered a remedy 30 years ago. But that was then. This is now. And medical science, which can separate conjoined twins, transplant hearts and decode DNA, could surely fix my wobbly vision before it got any worse. Couldn't it?

My consultant was considerate enough to look me in both defective eyes as she confirmed that any loss of sight associated with inherited retinal degeneration tends to be irreversible. Further tests, she said, would tell us more about the precise nature and progress of my particular condition. In the meantime, I would be well advised to stop smoking and eat lots of highly coloured vegetables. Particularly kale, which is high in the kind of antioxidants that could slow the degenerative process. "Can you smoke kale?" I wanted to ask. But it was no joking matter.

The possibility that I might have inherited a retinal disease had never been mooted. I didn't even go for regular eye tests until I was 42. My mother was told, back in the 1970s, that childhood diphtheria might have weakened her own sight, so she did not make the connection to grandad's disability. Like me, she was in her mid-40s when her left eye "went wrong", and I take comfort from her telling me that it seemed to settle down, and certainly got no worse, after the menopause.

My own daughter, Tilly, is 15. With luck, she will not have inherited this horrible thing. Either way, middle-age seems - and is - so far into her future that she sees no point in worrying about it. While telling her about my own prognosis, I tried to keep things light. We would manage, I said. Should my right eye go the same way as my left, we would simply adapt. She might even get sole use of my car as soon as she passes her driving test. And at least I would no longer notice the appalling state of her bedroom. Moments passed while she mulled everything over. I held my breath, hoping she wasn't going to be too upset. Then: "Mum," she said, "Will we get a free dog out of this?"

As Christmas approached I continued to keep things light. But inside, I was in turmoil. Above all, I dreaded returning to the eye hospital for further tests. What was the point? Conventional medicine couldn't cure me, it could only monitor the deterioration of my sight. Depressing? Umm... just a little. And what had they meant by "further tests"? My Outpatient Guide provided a glossary for procedures such as fluorescein angiography (a small injection of dye through a vein in the arm to highlight certain conditions at the back of the eye) and Optical Coherence Tomography (a scan taken through different layers of the eye). It also sought to reassure ("Nothing will touch your eye"), but it didn't.

The Royal National Institute of the Blind (RNIB) believes that the current level of patient support in eye hospitals is unacceptable. A nationwide survey found that "while clinical treatment of the eye is undertaken with diligence and professionalism, support for the person who is losing their sight is often left to chance". Where support exists, the survey found, it is often underfunded, dependent on charity and geography and insufficiently publicised. And with more than a million people a year being referred to clinics with serious eye disease or injury, this simply isn't good enough.

I have no bones to pick with my local eye hospital. Staff there eventually referred me to a genetic counsellor, who has been extremely helpful. But in those scary weeks following my initial visit, I did feel very much alone, and too baffled and overwhelmed to call the hospital switchboard with questions I should have asked while I was there.

Instinctively, I looked to alternative medicine for support and reassurance. A friend who is a medical herbalist turned me on to bilberries. Actually, this idea isn't as strange as it might sound. Bilberries, which contain the antioxidants anthocyanosides, are frequently used in Europe to treat eye diseases. The results of anthocyanosides are far reaching, benefiting a variety of eye-problems as well as varicose veins and haemorrhoids.

The anthocyanosides in bilberries work by fighting free-radical damage, which is responsible for cell membrane breakdown and damage to delicate organelles. A major contributant to free radicals is cigarette smoke. Bilberries are particularly important for diabetes sufferers. Anthocyanosides help the light-sensitive part of the eye known as the retina distinguish between light and dark. They do this by strengthening the eye capillaries responsible for carrying the oxygen-rich blood. Bilberries are also known to halt macular degeneration and cataracts.

Ian Marber, a nutrition consultant and director of The Food Doctor Limited, said: "People have been known to slow down or even stop any eye degeneration by eating a palette of bilberries a day, or by taking antioxidant supplements. There is unfortunately no way to reverse degeneration, but it can be treated by potent antioxidants contained in the fruits."

Another friend told me about a form of "eye yoga" designed to promote self-healing. Culpeper's Complete Herbal (1653), which I'd consulted while researching The Merrybegot, recommended drops of fennel, eyebright, white roses, celandine, vervain and rue infused in water. I liked the sound of that, although I balked at the seventh ingredient - "the liver of a goat chopt [sic] small". I bought a pirate patch from a fancy-dress shop and wore it over my "good" eye, the better to accept and understand my "bad" one. And I told myself that if I remained positive, and never smoked again, my right eye would not deteriorate - and the left one would even get better.

By the time I received dates for further hospital tests I had decided, quite irrationally, that conventional medicine was not on my side. It was cold. It was clinical. It could only give me bad news - probably after I'd spent at least three hours waiting in a queue. I didn't care that the tests might benefit research into inherited eye disorders - research that might one day result in a cure. I had plans to spend the winter solstice on Dartmoor, sitting on a rock and letting the setting sun bathe my eyelids. I had just bought a bilberry bush.

I was telling everyone that if the worst happened I would twirl honeysuckle round a white stick and flail about as fetchingly as the blind girl in The Village. I had romanticised my condition to the point at which it had almost become a fetish. And I did not want to be brought low by the bleak reality of NHS waiting rooms, and the drops they use to enlarge the pupils that leave you blinking like a mole, and feeling as good as blind already. So I cancelled those appointments.

Dennis Lewis, a counsellor for the Macular Disease Society (macular disease being the most common cause of registrable blindness in the UK) says that intense emotional responses are only to be expected following diagnosis of a serious eye condition: "They can range from denial and anger through to guilt, shame and anxiety and can lead to depression and even suicidal thoughts. Inevitably there is a feeling of loss of control over large areas of one's life."

So concerned is Mr Lewis about the need to address this issue that he is to co-present a workshop entitled The Psychological Impact of Sight Loss: recurring themes and the need for an holistic approach at this year's World Conference on Sight Loss. As for me, I remain anxious about the future, but not depressively so. Perhaps I am in denial. But while my writer's imagination can see a happy ending in positive thought and alternative therapies, I can at least feel optimistic, and in control of my own body.

My counsellor at the eye hospital says that I can change my mind at any time, and make new appointments for further tests. Having my choices respected like that makes me more inclined to keep my options open. In the meantime, there are fresh green shoots on my bilberry bush. And I am eating a lot of kale.

'The Merrybegot' by Julie Hearn is published by Oxford University Press, £5.99. Visit her website at www.julie-hearn.com

The Royal National Institute of the Blind (0845 766 9999); Macular Disease Society (0845 241 2041; info@maculardisease.org)