[Randomized field study of the etiology of strabismus concomitans].
After an introduction to the problems of binocular vision and an overview of the literature, the authors report on the reasons for undertaking this study and on its practical implications. Up to now, no other randomized study has been undertaken to our knowledge on children of this age group in such a large city as Vienna. All children in primary 3 classes in 20 out of the 256 elementary schools were examined ophthalmologically and orthoptically. It was found that hereditary factors are of statistically significant importance. Especially important for the ophthalmologist is also the statistically significant relation between the diagnosis poor range of fusion, poor fixation, incorrect Worth test for distance and/or proximity, and poor or lacking stereoscopic vision with the occurrence of strabism. The authors were astonished to find a remarkably high percentage of exophoria (58%), in contrast to esophoria (16%). It is interesting for prophylaxis and therapy that children originating from families where spectacles are worn, acted more cooperatively and tended to take the orders of the physician more seriously than those coming from families without eye problems. The promotion of genetic research related to squint and more counselling for couples wishing to have children or confronted with risk factor problems would be desirable, as well as the inclusion of more obligatory ophthalmological examinations in the mother-child medical "passport".