Loss of (part of) the normal field of vision, in one or both eyes. The retina is most sensitive at the centre of the field of vision; failure at the centre is thus more serious, because it affects reading and focusing on a particular object. Failure of a small peripheral area is sometimes not even noticed. To a large extent the fields of vision of each eye overlap, so that the healthy eye can sometimes compensate for the defective one. Loss of vision can be the result of eye disorders, or conditions of the optic nerve or the visual centre in the brain. Haemorrhage or inflammation of the retina cause failure of the central area of the field of vision. In cases of detached retina failure is sudden and normally runs from the edge to the centre. Retrobulbar neuritis causes central failure; a pituitary tumour can cause loss of field of vision in both eyes, with the areas closest to the nose remaining unaffected. Haemorrhage in the cerebral visual centre can cause complete failure, effectively the same as total blindness. If loss of a field of vision occurs a doctor should be consulted immediately; some causes, for example detached retina, require urgent treatment. A special test is available to establish the area and extent of loss of field of vision. Anorexia nervosa (’slimmer’s disease’) Clinical picture that occurs in young women, and characterized by a particular view of eating and body weight, leading to extreme loss of weight, Anorexia nervosa is a psychological disorder, but has significant – and sometimes fatal – physical consequences. Sometimes associated with freak periods of overeating and self-induced vomiting. The desire to slim can be so great that laxatives are used, causing dehydration. In spite of very poor physical condition bodily activity remains strikingly high; menstruation ceases. The patient does not consider herself slim, and denies abnormality in her eating pattern. If shortage of calories becomes so great that the body starts to break down its own tissue, all sorts of physical abnormalities result and the patient must be admitted to hospital. It is fairly generally accepted that anorexia nervosa is an expression of subconscious anxiety associated with adult sexuality and conflicts with which the patient has not yet come to terms. Anorexia nervosa is often preceded by a period of excess weight, and sweets and eating have often played a large role in the patient’s upbringing. Treatment is directed at the consequences of extreme weight loss and at underlying conflicts. Admission to hospital is often necessary to free the patient from a vicious circle in the family situation. Family therapy and psychotherapy are part of the treatment.