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The results obtained are not infallible, but in my experience are as accurate as those of
older children and in all cases detection of visual errors by reading a test card is only a rough
and ready method, and, if accurately done, can only show the manifest errors; such a test must
only serve as a preliminary to indicate which children need refraction.
At the Routine Medical Inspection and School Clinic the test used is always the Snellen
long distance test, and if a child reads 6/6 or 6/9 in each eye and has no sign of eye strain he is
passed as not requiring treatment, on the principle that latent errors which do not impair vision
or cause strain do not need correction, and that therefore it is unnecessary to refract such children
in order to ascertain the full degree of error.
In one respect however this procedure, though generally satisfactory, is inadequate, in that
it fails to detect the early myope. A child with a small degree of myopia will for a time read
6/6 without difficulty or strain and therefore remains undetected until such time as the vision
fails to a noticeable degree. From time to time children are referred to the Eye Clinic having
a visual acuity of 6/24 in each eye or less, who on refraction show 1-2 diopters of myopia. In
every case of this kind the child's record is examined to see why he was not referred sooner.
In most cases the previous Routine Medical Inspection showed normal vision, and therefore under
the present system no one is to blame for not obtaining treatment earlier. It seems clear however
that for some months the child has had an increasing loss of vision which could and should
have been corrected earlier by the provision of spectacles.
Myopia is the most serious defect in growing children in that the defect tends to increase
with age. Moderate degrees of Myopia can be satisfactorily corrected by lenses and good vision
obtained, but if the defect goes on increasing there comes a point when vision deteriorates in
spite of correcting lenses; there are changes in the fundus and in later life blindness may result
through detachment of the retina.
It is therefore extremely important that Myopia should be detected in its early stages
so that all myopic children may be kept under observation and given necessary treatment. Fortunately
not all Myopia is progressive, but it is only possible to distinguish between progressive and
non-progressive Myopia by frequent examinations.
In the Report of the Committee of Enquiry mentioned earlier the importance of the early
detection of Myopes was discussed at length and it was advised " that a more searching test is
necessary than the one at present employed in the schools for the detection of visual defects."
On administrative and financial grounds the Committee felt that it was impossible to suggest the
routine refraction of all children, and recommended a modification of the normal testing by
placing a + ID sphere before the reading eye, in all children who would otherwise be passed as
normal. The! Committee stated that under this test (reading through a + ID sphere) the
hypermetropic child will still read 6/6 or more—but the normal or slightly myopic child's visual
acuity will be lessened, and in the latter case may be diminished to 6/36.
This suggestion appeared a valuable one and was immediately put into practice at the
beginning of November, 1931, and was carried on for the whole of 1932, when I reported
at length in the Annual Report for 1932 on the results obtained. These were very disappointing,
as it was found that 90% of the children, whose vision would be passed as normal under the
ordinary Snellen test, had their vision adversely affected by the addition of a + ID sphere to
the reading eye. According to the Report of the Committee of Enquiry such children would
either be Emmetropic (normal) or Myopic, though one could not disregard the probability that
small degrees of Hypermetropic astigmatism would also cause diminution of visual acuity.
The number of children tested at Routine Medical Inspections in 1932 whose vision was
adversely affected by reading through a + ID sphere was 2,770, so that it was impossible in the
course of routine work to refract them, and the difficulty of detection of the early myope was
not helped by this additional test.
It appeared possible, however, that the degree of diminuation of vision might afford
some clue, as one supposed that the early myope might be more severely affected by reading
through a + ID sphere than the emmetropic or slightly Hypermetropic Astigmatic child.
In my detailed reports (see Annual Reports of the School Medical Officer 1931 and
1932) I showed that in 1932 only 0.81% of the children had their vision diminished by 5 or
more Snellen lines, i.e., that a child reading 6/6 with unaided vision read only 6/36 or 6/60
through a + ID sphere. The actual number was 25, and the number being small an endeavour
was made to refract them.
The next category, viz., decrease of 4 Snellen lines, contained 414 children, a number too
large to refract unless made the subject of a special enquiry.
The 25 children were treated as special cases and seen on a Saturday morning, but, unfortunately,
only 20 children attended. The results here were inconclusive. All the errors were
small and in most cases there was 0.25 diopter of astigmatism (9 Hypermetropic Astigmatism,
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