THE DIAGNOSTIC SIGNIFICANCE OF RETROBULBAR NEURITIS

I)EAR SIRS,-If no abler pen than mine has been moved to comment upon an article by Rosa Ford in your March number on the Diagnostic Significance of Retrobulbar Neuritis, may I be allowed the ever ungracious task of the critic ? There appears to be a noticeable disproportion between the evidence and the conclusions put forward in her paper, which surely calls for some comment. It is generally acknowledged to be unwise to draw conclusions from an isolated case history, and I would suggest that in this instance even the conclusions themselves are not the most attractive which could be )ut forward. We are asked to believe that an attack of retrobulbar neuritis originated from a closed nasal sinusitis of which there were neither symptoms nor signs. (" All search for a cause proved fruitless "). We are further asked to believe that eight years later this same insidious and invisible sinusitis gave rise to rheumatoid arthritis and recurrent iritis. After eight years of unhindered gestation there are still no symptoms of sinusitis, and no recorded signs; in other words, no evidence of sinusitis preceding interference with the nasal cavities. It is hardly surprising to learn thiat the application of argyrol and glycerine to the nasal passages provoked a flow of mucus; it is distressing, but not remarkable, to learn that after three weeks the discharge contained lumps of muco-pus. I am told that this experience is not without precedent among those who attack the nose on general principles alone. Evidence as to the cause of the retrobulbar neuritis in this case is (I venture to suggest), entirely lacking. There is no more evidence to suggest that it was due to an undetectable nasal sinusitis than there is to suggest that it is due to an undetectable disseminated sclerosis; but the balance of probablity, from common experience, is surely overwhelmingly in favour of the latter. It is well known that retrobulbar neuritis is not uncommonly followed in later life by manifestations of disseminated sclerosis; it is a common experience to find no certain signs of disorder of the central nervous system at the time of an attack of retrobulbar neuritis in early adult life, and they may not develop for twenty years; but can one dare to say with certainty that the case reported who is not yet forty years of age, and was but twenty-eight at the time of the latest record of her condition-may not yet develop the disease ? Is contraction of the visual fields in a young woman of twenty to be taken as evidence of closed nasal sinusitis as against disseminated sclerosis ? \Vith regard to the later historv of her progress, surely rheumatoid CORRESPONDENCE 233