The fun of reading in the evenings is often clouded by the fear that the eyes could be damaged in the long term. However, this concern is unfounded, as a closer examination of the visual process in the dark shows. On the retina of the eye are two different types of light receivers (photoreceptors). The rods are highly sensitive to light and responsible for the night vision and the cones are claimed in color vision.
Visual purple is transformed
When light falls on the retina of the eye, it is absorbed, and the visual purple (rhodopsin) is chemically transformed and is no longer available to the eye until its regeneration. This regeneration is only possible when the eyes are closed or when no further light incidence can take place on the retina.
Another prerequisite for the regeneration of the visual purple is a sufficient supply of provitamin A (beta carotene) which occurs mainly in carrots, cabbage and spinach. Lack of vitamin A can even lead to night blindness, corneal inflammation or dryness of the eye.
Although reading at dusk leads to an increased degradation of the visual purple, but does not cause long-term damage, since the visual purple regenerates. However, it is not advised to drive in the dark after reading because the amount of visual purple and thus also the sight may have decreased in the course of the evening. The next morning, however, the eyes are fully powerful again, since the visual purple has rebuilt completely during sleep.