The use of the ophthalmological services during the preschool age, ocular findings and family background.
The series consists of 12,059 children followed-up since their mothers' pregnancy. Of these children, 5.2 percent had visited an ophthalmological department during their first five years. Visits were significantly more frequent among the children of social classes I to III than among those of class IV and the farmers', and thus the frequencies of the diseases based on diagnoses given in the ophthalmological departments were also higher in social classes I to III. These children clearly had the best opportunities to have their diseases diagnosed at an early age. Squint was the most common diagnosis with the prevalence being 18.4 per thousand for the children in social classes I to III and 15.9 for the total series. The second largest group consisted of children without any positive ocular finding. These were mainly risk children having some other disease. The third most common diagnosis was dacryostenosis--its incidence in social classes I to III being 9.4 per thousand and that in the total series 7.9 per thousand. Squint correlated negatively with birth weight and was more common among children with some other disease, especially some nervous or mental disease. Dacryostenosis correlated positively with gestational age. If the mother smoked during the pregnancy she was more likely to give birth to a child with squint and less likely to bear a child with dacryostenosis.