We gather information first and foremost with our eyes. We live in a visual world. The eye is the most important sense organ of all, delivering more than 80 percent of all the information that reaches our brain. Without light, this would be impossible – light is the medium for visual perception.

In poor light and darkness, we cannot see well; we feel insecure and have difficulty getting our bearings. Artificial lighting at night gives us a sense of security.

For vision, we need only the radiation in the visible electromagnetic spectrum. During the course of evolution, our eyes have adapted specially to the wavelength region of sunlight, which pervades the Earth atmosphere in abundance and with a sufficient degree of constancy.

From eye to brain

Our eyes transmit the information they pick up ten times faster than our ears. The brain processes the information and computes a spatial impression from the marginally different images transmitted by the right and left eye. This is what enables us to see in three dimensional depth and also to judge distances.

In judging distances, the brain distinguishes between nearby and remote objects partly by registering the blue content of the light. Objects that are not so far away appear in warmer, bolder colours while more remote objects look bluish and pale.