Is the Jeweler's and Watchmaker's Job a Strain on the Eyes?
An Old Prejudice-Bad Conditions Must Be Avoided
Scientific investigation has proved, however, that this supposition is incorrect. While, for instance, 30 to 40 per cent of typesetters and lithographers are found to be nearsighted after many years of work, there is only about ten to fifteen per cent of nearsightedness among jewelers and watchmakers.
Short Sight and Headaches
Moderate nearsightedness (myopia) does not prevent a jeweler or watchmaker from working. In nearsightedness the eyeball is too long from front to back, and light rays entering the eye focus the image in front of the retina instead of exactly upon it. Nearsighted people can see objects close at hand, but distant objects appear blurred. Normal nearsightedness usually improves with the course of years. Doing very close work is a great strain for nearsighted eyes especially during the period of growth.
Well fitted concave glasses may eliminate all troubles originating from nearsightedness. A nearsighted watchmaker whose glasses are too weak is working with the upper part of his body bent forward. He looks through the rims of his glass in order to see more clearly.
The degree of nearsightedness and of other optic disturbances is determined by the strength of the lenses which are required to correct it. The degree of concavity or convexity to which the lenses are ground is expressed in diopters. The lenses scatter or gather the rays of light which fall upon the eyes so that the correct spot on the retina is reached and a sharp image of the object is projected upon it. Other disorders of vision can be corrected in practically the same way.
Astigmatism is concerned with a rotation of the eye to the side. There is a difference in degree of refraction in different meredians. Vision is then blurred at close range as well as at distance. Lenses which are ground correspondingly are of value - in such cases too. There are some methods of treatment which try to exercise the eye muscles and strengthen the eyes in this way. However, this may work out, it is sure that a person with nearsightedness, astigmatism and similar troubles has to wear glasses if he wants to do his work in, the most efficient way.
In farsightedness (hyperopia) the eyeball is too short from front to back, and light rays entering the eye focus the image back of the retina.
Such eyes cannot see objects near at hand without giving considerable extra work to the muscles of accommodation. This often results in eyestrain, but the condition can be corrected by glasses. Usually between the ages 40 to 50 -
Old Sight (presbyopia)
begins. It is a normal change due chiefly to loss of elasticity of the lens of the eye. A jeweler of 42 or 35 who has always had a good eyesight may note that he must push his work (or his head) farther away in order to see dearly. He prefers strong illumination. This, by contraction of the pupil, improves the vision temporarily.
Different glasses are needed in this condition, for working, reading, writing at close range, and for seeing in distance. In such cases either two pairs of glasses are used; or glasses are used the upperpart of which is ground for distance the lower part for objects at close range. Otherwise the presbyopic may suffer from pain, fatigue, headache and lacrymation, all of these symptoms being more marked with poor light or at night with artificial illumination.
and strong illumination help greatly to avoid eye-strain, and that is important to prevent additional eye troubles. Improper lighting shortens the duration of normal seeing. The same holds true for flickering light. In bright light tinted Or dark glasses are desirable. Sunlight and lamplight glaring into the eyes or reflected from such surfaces as glossy paper and tabletops and walls are harmful. Proper care can prevent unnecessary strain on the eyes and prevent very unpleasant disturbances in an easy way.