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85
Two or three years ago some facts were brought to light in the annual report
which appeared to clinch the hypothesis that the chief cause of the development
of myopia was school work. It was noted that whereas amongst Gentile children
there is always more visual defect in the girls than in the boys, and this adverse
incidence upon girls increases with school age, amongst Jewish children on the other
hand the boys suffer more than the girls, and the incidence upon boys is more apparent
the older they grow. It was thought that the fact that Jewish boys especially have
to attend evening classes and do much work under conditions of artificial lighting,
not always well adapted for the purpose, accounted for this reversal.
This discovery caused perturbation and has led to further research. Dr. A.
Sourasky in particular paid close attention to the question and he published the
results of his enquiry in the British Journal of Ophthalmology for April, 1928.
1,649 boys in the Hebrew Evening Classes (Talmud Torahs) were examined by
Dr. Sourasky and on a similar basis 600 non-Jewish boys were examined at Council
schools in the East end by the Council's staff. The first broad analysis of the
results of the comparison proved that the facts which were set out in the annual
report were confirmed, 43.2 per cent. amongst Jewish and 21.7 per cent. amongst
non-Jewish boys proved to be defective.
Upon closer analysis of the facts, however, Dr. Sourasky has come to the conclusion
that the explanation cannot be sought in the inference that the higher percentage
of visual defect amongst Jewish boys is due to increased use of the eyes in
school work, rather he suggests it is due to inherent racial variation.
It is impossible here to set out all the tables and figures upon which this deduction
is based. He points out, however, that there is no greater advance amongst Jewish
boys during school life than amongst non-Jewish, which tends to negative the suggestion
that the heavy evening work is to be invoked to explain the greater total
incidence of defect upon the former. The greater defect amongst Jewish boys as
opposed to non-Jewish is already apparent before attendance at Talmud Torah
begins.
In order to test whether there were racial qualitative differences as well as
quantitative differences a research was carried out amongst Jewish and non-Jewish
children attending hospital for visual defect. There were 516 Jewish and 892 nonJewish
cases. The dominant suggestion obtained from the analysis of type of case
in this part of the research is that while hypermetropia is the predominating refractive
error in both, low hypermetropia is the common error amongst the Jewish,
while high hypermetropia is the more common amongst non-Jewish children.
Dr. Sourasky, therefore, believes that Jewish children start from a level of low
hypermetropia in the beginning while the non-Jewish children start from a level of
high hypermetropia, and the forces of growth by themselves unassisted by special
conditions such as excessive study explain the passing over of a larger number of
Jewish than non-Jewish children into high myopia. But this explanation as yet
does not account for the reversal in the incidence of visual defect in the sexes as
between non-Jewish and Jewish children. Dr. Sourasky has, therefore, analysed
the incidence of visual defect in four groups—Jewish boys, Jewish girls, non-Jewish
boys and non-Jewish girls, and he finds that in both Jewish and non-Jewish girls
the tendency is for hypermetropia to a greater extent than in boys to persist and
not to pass over into myopia. There is according to this very ingenious hypothesis
a racial factor which accounts for the excess of myopia in Jewish boys and a nonracial
sex-linked factor which accounts for the excess of visual defect (consisting to
a large extent of persistent hypermetropia) amongst non-Jewish girls.
In criticism of this hypothesis perhaps stress should be laid on the fact that
Dr. Sourasky's cases in which the refractive error was determined were derived from
a selected group, i.e., children who had sought relief at hospital and therefore are
not necessarily representative of the school population.