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V.F. (9.11.19).
Before mydriatic RV 6/6p LV 6/6p
+ 0.5
+ 0.5
c + 1 sphere RV 6/36 LV 6/36
— 0.5
— 0.25
M.T. (29.5.18).
Before mydriatic RV 6/6p LV 6/6p
+ 0.25
— 0.25
c + 1 sphere RV 6/36 LV 6/36
0
— 0.25
B.W. (21.5.23).
Before mydriatic RV 6/6 LV 6/6
— 0.25
0
c + 1 sphere RV 6/24p LV 6/24p
— 0.25
0
W.H. (15.2.20).
Before mydriatic RV 6/6 LV 6/6
— 0.25
- 0.5
c + 1 sphere RV 6/36 LV 6/36
— 0.25
-0.5
It will be noticed that not all these children exhibited a difference of 5 Snellen lines
with + 1 sphere when tested at the Clinic immediately before the Homatropine was installed.
In most cases the discrepancies are slight and can be accounted for by the varying conditions
pertaining in the schools—particularly as to lighting of the test card—also several months had
elapsed between the testing at school and the subsequent refraction. One case only suggests
an error in the first testing, viz., the boy P.D., who read 6/12 through + 1 sphere.
In three cases only was it considered necessary to prescribe spectacles—two because
there were now symptoms of strain and their sight was improved by correcting their small
errors, and one (J.G.) because the vision in his left eye was found to have deteriorated to 6/36
since he was tested in school, which in his case had been 8 months previously. His vision
then was RV 6/6, LV 6/9.
The other 17 were marked for observation and will have their vision tested whenever
the Medical Officer visits their school instead of waiting years for their next routine examination.
Spectacles were not ordered as I do not consider it either necessary or justifiable to
saddle children with spectacles for the correction of small errors which are causing neither
bad vision nor strain.
Twenty cases is too small a number from which to draw conclusions, they can only
serve as a guide as to what may be expected in similar circumstances. All the errors are small,
and in most there is astigmatism of 0.25 diopter in either one or both eyes. It would appear
also that slight hypermetropic astigmatism as well as slight myopia causes a large decrease in
vision where a + 1 sphere is used.
It is quite possible that similar results would be obtained if children in the
lower Snellen Decrease groups were also refracted ; one cannot tell without refracting them.
A further rough age analysis has been made of the figures, classified according to type
of school and sub-divided according to sex.
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