[Treatment of strabismus with focused prisms in 1984]

The use of prisms in treatment of strabismus not only varies according to the author involved but often, a same author will change his opinion on the subject as time goes by. In the first case aetiopathological conceptions and the finality of treatment differ, in the second case improved theoretical knowledge and new possibilities in examination techniques and treatment etc., come into play. For this latter reason we wish to give complementary information and generally revise the publication on the use of prisms published in 1973 (18). The revised version in no way invalidates the previous work, it brings it up to date and gives further information on the severe forms of strabismus which, at the time of the first publication, constituted the failure group. These severe forms (both lesional and functional), the percentage of which has mostly increased during the last 15 years, are probably a consequence of 'suffering' during either the foetal or neo-natal stage. It could be that this 'suffering' gives rise to a minute isolated lesion within the sub-cortical motor centres (microlesions as described by neuropaediatricians). In situation, there are intermediary forms and come between the organic oculomotor disturbances of the cerebral palsied child and the strictly functional strabismus of the child who is otherwise normal. We have modified and adapted our diagnoses and techniques in view of the multiplicity of such forms and their resistance to conventional therapy. A better understanding of the process responsible, use of more sensitive methods of exploration, a longer period of functional readaptation and new techniques (particularly surgery-) all have a part to play in the new therapy. Where operating is concerned changes apply to the time selected, technique and number of operations performed: two or three stages are necessary. We give a general view of the extreme variety of clinical forms of strabismus and their causes and then give diagnoses and outlines for therapy based on four different type-cases. Clinical facts indicate that in severe forms it is possible to obtained a cure (bifoveality) on condition that the sub-cortical organic damage is very slight and that the optomotor dysfunction (which is its consequence) can be inhibited through satisfactory cortical functioning. However, such treatment requires rigourous participation of both the family and the child over a period of years. Unfortunately this treatment is possible only in a small percentage of cases.