The relationship of myopia to school work / by W. B. Inglis Pollock.

  • Pollock, W. B. Inglis.
Date:
1906
Catalogue details

Licence: In copyright

Credit: The relationship of myopia to school work / by W. B. Inglis Pollock. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    compression is brought about by all the extrinsic muscles actino- together, while the tendon of the superior oblique plays the chief rdle. • , • ^, , , , The important point is that in the healthy eye myopia scarcely ever originates except during childhood and youth. For it is only then that increased intra-ocular pressure pro- duces bulging of , the tunics of the eyeball, as in buphthalmos. Thereafter the sclerotic has become too rigid and inelastic, so that in glaucoma the optic nerve entrance alone yields to the increased tension, where the lamina cribrosa is but a third of the thickness of the sclera. Heredity is a predisposing factor, but it is quite common to find that the parents of myopic children are not themselves near-sighted. Conversely, where one or other parent is myopic, the offspring do not necessarily become so. In such cases it is always advisable to take greater precautions against the onset of myopia. Hypermetropic astigmatism, and any 'factors causing a diminution of the visual acuteness, are of great etiological moment. This came out distinctly from my investigations. An illustration giving the various errors of refraction in percentage throughout school life showed a slight rise in the emmetropic curve. The myopic curve (the figures for which are given in the table accompanying this paper) also increased, and by a distinct step-like progression in the highest ages. The hyper- metropic curve, on the other hand,constantly declined through- out the entire period. The point to be emphasised is, that by inversion it could have represented the myopic curve. Such but confirms what was already known. Hypermetropic astigmatism, under the pressure of near work, passes into mixed astigmatism, and ultimately becomes myopic astigma- tism. We are thus given one of the most important indica- tions for the prevention of myopia. Corneal nebulae and congenital cataract frequently bring on myopia as a compli- cation, the reason being that the imperfect vision urges the child to approximate objects to the eyes in order to obtain the larger retinal image. Prophylaxis.—The prevention of myopia is one of the im- portant branches, if not, as already indicated, the origin of school hygiene. It has given us the large, bright schoolrooms, and almost palatial buildings of the present day. The seats, desks, books and paper, blackboards, and all the other furnish- ings of the schoolroom, as well as the arrangement of the lessons, are all subject to the principles laid down by Cohn.