This section is from the book "Smith's Family Physician", by William Henry Smith. See also: Natural Physician's Healing Therapies: Proven Remedies that Medical Doctors Don't Know.
Squinting may be caused by some defect in the formation before birth; or it may be induced by bad habits; such as the imitation of parents, nurses or schoolfellows, if they happen to squint, or by constantly looking at spots or pimples on the nose; or it may follow affections (such as a sty) which render motion of the eye painful; and during which the patient turns the eye inwards, and keeps it motionless. It may be caused by using One eye constantly to the neglect of the other: It may be observed, that nearly all short-sighted persons have more or less tendency to squint, for the following reason. They never use both eyes whilst they are reading, or examining small objects near the eye; but sometimes use the right eye, and sometimes the left: If, however, they were by accident to persist in using one only, it would become stronger by use, and the other weaker by disuse: and the weaker might squint. In this manner squinting has been known to occur after one eye has been for a long time shaded in consequence of an inflammatory attack; which shows the expediency of always covering both eyes when a shade is necessary.
Squinting is sometimes a relic of fevers or other diseases. It may be induced by irritation or disorder of the stomach and bowels, teething, worms, constipation, etc. It may be caused by fright or violent fits of passion; and in some children it always appears when the health is out of order, and disappears when it is restored. Lastly, it may be caused by some disorder of the brain.
Thus, it is pretty frequently the precursor of water on the brain or convulsions in children; and when it is associated with dropping of one or both eyelids, and. with an unusual sleepiness, or torpor of the intellect, or faltering in the gait, some mischief within the head may fairly be anticipated.
If the affection is recent, it may perhaps be removed by judicious medical treatment. The patient should be kept away from the society of every squinting person who might be imitated. Any disorder in the stomach or bowels should be removed by purgatives, antacids, and tonics; and, if the patient is a weakly child, and if the squinting has followed a severe illness, a course of Wine of Iron, or Mixture of Iron, or Citrate of Iron and Quinine, might be of service. An endeavour should be made to strengthen and exercise the squinting eye, by covering the sound one with a light shade, for one or two hours every day; but this must be done with moderation; because it has happened, that, while a squinting eye has been cured by this means, the sound one has been weakened by seclusion, and has been made to squint instead. If a child is beginning to squint, it should be carefully watched, and be told to endeavour to correct it; close application to study should be interdicted; plenty of exercise should be taken in the open air; and if the sight is short, a pair of shallow concave spectacles should be used.
But, if the squint is of long standing and habitual, very little good can be done unless the muscle which pulls the eye out of its place is divided.