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.