There were, however, hints that the xenon arc was also more effective than the argon laser in preserving vision. Some would take that paradox to support the argument that the more substantial retinal ablation also removes more of the source of a
factor which drives the
onwards. In the older,
betic, vasoproliferative retinopathy is and it is the
extensive variants of "background" retinopathy which threaten vision. An interim report on the results of a small multicentre trial, sponsored by the British Diabetic Association,11 was restricted to older patients with diabetic maculopathy. In 76 patients with both eyes roughly equally affected with retinal hxmorrhages, exudates, and macular oedema with visual acuity of 6/9 or less, or with circinate hard exudate involving the macular region with vision better than 6/9, a randomly selected eye from each patient was submitted to xenon-arc photocoagulation applied locally to lesions lateral to the macula, more generally to all visible lesions, or to the centre of circinate exudates. More control eyes (18) than treated eyes (8) deteriorated to blindness over a follow-up period of up to three years. The mean slowing effect of treatment on the rate of deterioration of visual acuity was statistically significant but small, with no obvious trend to increase with passing time and most evident in patients with intermediate degrees of visual deficit at baseline. The design of this trial was good but its scale hardly adequate to answer its primary questions. So we now seem to have a simple, low-risk treatment which will, in the short term at least, delay visual deterioration in diabetic retinopathy in patients with retinal neovascularisation, especially when this is more than slight and when it is accompanied by retinal haemorrhage, and also perhaps in older patients with maculopathy. In "ordinary" background retinopathy risk to vision is low and uninfluenced by photocoagulation. To take advantage of this new information (and to react promptly to further developments) we should consider redeploying our clinical resources. A first step should be the repeated, systematic ophthalmoscopic screening of patients under adequate conditions of mydriasis, and at intervals determined by the retinal appearance and by the type and duration of diabetes. A for verification questionable lesions stage should probably include fluorescein retinal angiograms which show up small tufts of new vessels which may escape ordinary clinical examination. Referral of patients with treatable lesions to an ophthalmologist with access to a photocoagulator should follow without delay, and treatment by aimed photocoagulation, retinal ablation, or both (and to include new vessels on the disc where the 11. Interim
Study. Lancet, 1975,
argon laser is available) should be performed. A planned schedule of follow-up observations and additional coagulation completes the schema. Where all of this cannot be done within a single hospital, ad-hoc district, area, or even regional ar-
rangements should be made. We
overlook the anxiety of the patient for his vision as he observes the increased interest and activity centred on his eyes. Nor must we sweep into this system patients with retinopathy unsuitable for treatment. For simple background retinopathy we can and need do little but observe and improve diabetic control. When extensive retinal or pre-retinal fibrosis is already present, photocoagulation may accelerate contraction and hasten retinal detachment. Very occasionally vitreous haemorrhage may occur soon after treatment, especially if large venous channels are too closely approached. Diabetic retinopathy is the most readily visible and clinically eloquent manifestation of a process which is progressing in other tissues and organs, not least the renal glomerulus. Enthusiasm for photocoagulation, a destructive process and clearly not the end of the road in the treatment of diabetic retinopathy, should not deflect more general efforts to prevent diabetic microvascular disease. This aspiration may well defy fulfilment until we have made a deeper penetration into the continuing mystery of the causation of diabetic microangiopathy.
The Future of
THE specialty of community medicine emerged in Britain from a union of the Todd Commission on Medical Education, the Hunter Working Party, and the reorganisation of the National Health Service. A turbulent infancy and childhood aré almost inevitable since each of the three parents has different expectations of the child. And already we are hearing the cries of doom and disaster. Before and even after Todd, medical students seldom opted for careers in public health or community medicine, and there is concern that the quality of entrant to the specialty is poor. This week Dr HEATH and Dr PARRY (p. 82) put forward some ideas on the future of community medicine and they make a valuable contribution in the
emphasis they put on proper manpower planning. Perhaps the figures they cite, with their promise of rapid promotion for the able, will encourage more doctors to choose this sphere. HEATH and PARRY do, however, seem to overlook some of the serious problems which community medicine has to tackle. The first
role and identity. The Hunter working party slightly confused the issue by concentrating on management aspects. In fact, only concerns
medical officers-that is, about the 700 consultant-grade posts in the 100 out of specialty—have a major managerial remit. The other 600 should, if they are doing their jobs properly, play an advisory rather than an executive role. They should practise the art of epidemiology and contribute towards the setting of objectives at each level of the service, measuring and evaluating need, demand, and outcome. Thus the basis of community medicine (and what makes it attractive) is the application of epidemiology to the improvement of health care. WARREN and ACHESONl are among those who have spoken for epidemiology and medical statistics as the two basic components of community medicine. And this raises another difficulty-that of training. Entrants to community medicine, unlike those to many of the clinical specialties, have to acquire a deep knowledge of subjects they have scarcely encountered during undergraduate medical training. They also have to appreciate the contributions of social science, management, and economics to community medicine. HEATH and PARRY emphasise the importance of a proper academic training and criticise the consortium approach because of discontinuity of training and excessive travelling-time. In their view, fulltime attendance at a university course, while not always practicable, is the most satisfactory form of training. Here we disagree. Many doctors training for other specialties have to combine the service and academic aspects of the job, and indeed separation of these is one of the major criticisms that has been levelled against community medicine in the past. Modular teaching seems ideally suited to encourage a closer relationship between theory and practice. Finally, HEATH and PARRY discuss the cut-backs in expenditure on health and their implications for community medicine. Their suggestion for the creation of a subspecialist grade would be a step backwards and should be rigorously resisted. The problems of senior hospital medical officers have only lately ended, while the difficulties of medical assistants in other specialties are only just beginning to emerge. Community-medicine specialists contribute to the health of population groups in a very direct way. That their efforts in prevention, planning, and evaluation have not yet received the attention they deserve can be attributed largely to difficulties arising from reorganisation and a change of role. Further evidence of the current difficulties of community medicine or public health comes from the work of an American committee, under the chairmanship of Dr CECIL SHEPS, on Higher Education for Public Health.2 As this report shows, the spearea
1 Warren, M. D., Acheson, R. M. Int. J. Epidem. 1973, 2, 371. Education for Public Health. Report of the Milbank Memorial Fund Commission. Prodist for the Milbank Memorial Fund, 1976.
faces similar problems in the United States. There is the same concern about the quality and quantity of medical entrants to public health, although increasing numbers of people from other disciplines do choose this sphere of activity. There is concern too, to improve the training and exposure of graduates in public health, who should be able to identify health-related problems in a community ; to develop priorities; to formulate policies and make decisions; to perform management and administrative functions; to educate the community ; to advise, consult, and support community service programmes; and to carry out research and evaluation. These are very similar to the British objectives. The report also emphasises the separation of research, education, and practice, and the need to bring them together-a difficulty as much in evidence in the U.S.A. now as it was in Britain in the past. GRUENBERG, in a personal statement as a member of the commission, makes the point, with which we agree profoundly, that the Sheps report itself does not emphasise sufficiently the basic area of endeavour in public health-namely, epidemio-
logy. Only by giving proper place to epidemiology can community medicine attract the best young minds, and only epidemiology can reveal the impact of the specialty on health. Epidemiology is an exciting and productive discipline.
IMMUNE COMPLEXES IN RHEUMATIC DISEASE
THE notion that immune complexes play a part in the pathogenesis of rheumatoid arthritis and other "collagen" diseases has good circumstantial support on immunological grounds.1 2 In rheumatoid arthritis IgG, IgM complement, and rheumatoid factor have been detected in the synovium of affected joints and the synovial fluid contained immune complexes. The ratio of complement in synovial fluid to that in serum is lower in rheumatoid than in non-rheumatoid effusions, suggesting local complement consumption in immune-complex formation. There is evidence that immune-complex deposition is responsible for glomerular and vascular lesions in systemic lupus erythematosus (s .L.E.), and removal of circulating immune complexes by plasmapheresis is said to produce clinical improvement.4 Similar mechanisms may operate in various forms of vasculitis, including polyarteritis nodosa. If such local tissue damage in the joints and blood-vessels is immunologically mediated by immune complexes, what is the nature of the antigenic stimulus ? In some cases, vasculitis seems to be induced by antigens associated with identifiable infections, foreign proteins, or 1. Glynn, L. E. in Clinical Aspects of Immunology, p. 1099. London, 1975. 2. Ziff, M. in Progress in Immunology II, p 5. Amsterdam, 1974. 3. Koffler, D., Agnello, V., Thoburn, R., Kunkel, H. G. J exp. Med. 1971, 134, 169. 4. Verrier Jones, J., Cumming, R. H., Bucknall, R. C., Asplin, C. M., Fraser, I. D., Bothamley, J., Davis, P., Hamblin, T. J Lancet, 1976, i, 709