Imagine that there is no electricity, and the ancient methods of lighting – candles and lamps – are not available for whatever reason. In this case you will lose most of the day. You will just have nothing to do in the evenings, immediately after the twilight. We all are surrounded by artificial light, which we use for everything – from cooking to reading. But this artificial lighting has so thoroughly merged with the way of life of a civilized man, that we simply do not notice it. But artificial lighting is one of the main factors affecting the vision.
The best light for vision is of course, natural sunlight. But even here there are some nuances: for example, it is not recommended to look at the bright sun without dark glasses and a long stay in the scorching sun without eye protection can lead to impaired vision and contribute to the development of various diseases of the eye. The healthiest option is a little scattered daylight. But even during the day, such a light might not be enough. If you are in the room, the degree of light during the day varies due to the movement of the sun with respect to your side of the building. During the winter period it becomes darker much earlier and the light itself can be too dim and we need to use extra artificial light, but what artificial light is good for the vision?
As expected, people have not yet invented the perfect artificial light. There are still many debates about the traditional incandescent and fluorescent lamps of daylight. Incandescent lamps are in some ways superior than fluorescent lamps, but both of them do not provide an ideal light effect. The main advantage of incandescent lamps is that they do not flicker, so it does not give stress to the eye. The light of these lamps is distributed evenly and smoothly. The disadvantage of incandescent lamps is the low efficiency and, as well as the yellow tint and weak light intensity. The main advantage of fluorescent lamps is white light of high intensity, suitable for lighting large spaces. The main drawback is the flicker, though imperceptible to the naked eye theoretically can affect vision.
Too dim light ruins eyesight and makes you fall asleep, too bright light makes you feel tired (a common symptom is headaches due to overexertion of the eye muscles). The best option is a moderately intense light, in which you can see everything fine, but the eyes still feel comfortable. To achieve this effect, you can combine general and local light source. Overall light should be scattered, non-intrusive, and the local light should be in two or three times more intense than the general one. It is desirable for the local light to be controlled and directed.
Imagine that there is no electricity, and the ancient methods of lighting – candles and lamps – are not available for whatever reason. In this case you will lose most of the day. You will just have nothing to do in the evenings, immediately after the twilight. We all are surrounded by artificial light, which we use for everything – from cooking to reading.