Diagnosis
Usually glasses are prescribed by an ophthalmologist through a prescription. Either the optician or an optician then carries out an eye test with the patient. First, a purely geometric-optical measurement of the eyes is carried out.
For this, the patient sees through a so-called autorefractometer. The result indicates whether glasses are required. This objective test is followed by the subjective eye test.
Together with the patient, the strength of the spectacle lenses is determined by reading numbers or images from a vision test chart. The left and right eye are adjusted separately and optimally matched to each other. The respective lens strength is indicated in dioptres (abbreviation: dpt).
A minus sign is given for myopia and a plus sign for hyperopia. In an eye test, a so-called cylinder can also be determined. It corrects vision, e.g. in the case of astigmatism in a certain plane.
Pure farsightedness, old-age and short-sightedness are treated conservatively with single-vision glasses. For this purpose, both forms of farsightedness are corrected with a convex (raised on both sides) converging lens – reading glasses. Near-sightedness, on the other hand, is treated with a concave (hollow surfaces on both sides) diverging lens – distance glasses-.
When both the letters from the newspaper and objects in the distance are perceived blurred, there are so-called progressive glasses, which provide a seamless correction for all areas between distance and near. A corneal cone formation or irregular corneal curvature can only be corrected inadequately with glasses. Eyeglasses must always be adjusted correctly, otherwise health problems may occur or the person concerned may not be able to see completely despite the correct thickness of the lenses. Surgical treatment of ametropia can also be carried out using various techniques (e.g. laser therapy).
Rehabilitation
Glasses are only used to alleviate the symptoms, i.e. they enable the affected person to see normally or optimally for his or her condition. Although vision may also regress over time, the chances of recovery by wearing glasses are usually not expected.
Prophylaxis
There is no clear precaution to avoid defective vision. Excessive consumption of televisions and computers is not recommended. People who nevertheless have to work constantly with a PC in their job are advised to have regular check-ups.
Certain guidelines exist for the same occupational groups. In addition, eye drops should prevent the eyes from drying out and overexertion. All in all, glasses are probably the most useful aid for patients with impaired vision. Even if they sometimes interfere with everyday life (e.g. sports), constant development ensures that they are more comfortable to wear.
