Eyesight, and how to care for it / edited by George Black.

Date:
[1888]
Catalogue details

Licence: Public Domain Mark

Credit: Eyesight, and how to care for it / edited by George Black. Source: Wellcome Collection.

    91/168 (page 87)
    the eyes are directed to some near object; then oc- casionally even when a distant object is looked at steadily or carefully, particularly if the child is not well, and is therefore less equal to the strain than usual; and, finally, one eye remains constantly turned in towards the nose. The origin of the squint is fre- quently referred to some attack of sickness, as measles, scarlet-fever, whooping-cough, or convulsions. This may be merely a question of coincidence, as these dis- eases occur very frequently at about the age when squint is developed; or they may act as exciting causes, by reducing the strength of the patient so that the eyes are less able to bear the strain ; but the real cause is a defect in focus, due to the fact that the eye is not properly formed — is not according to measure. It will be remembered that when a want of har- mony in the action of the external muscles of the eyeball causes the image to fall on parts of the retina that do not correspond, double vision at once results (see page 42). To avoid this annoyance, persons with squint learn to use only one eye, and the image on the retina of the other is said to be suppressed. In consequence of this constant suppression, the vision of the squinting eye becomes greatly impaired, in fact, accurate vision is lost, though the eye remains perfectly healthy. In the early or periodic stage, before it becomes