Why good vision is so important

The human senses are our contact to the environment. The human brain combines the fireworks of neurons of seeing, hearing, smelling, tasting, and touching into a meaningful whole. But we don't think about our senses until an organ stops working.

Humans have five senses: the eyes to see, the tongue to taste, the nose to smell, the ears to hear, and the skin to touch. By far the most important organs of sense are our eyes. We perceive up to 80 per cent of all impressions by means of our sight. And if other senses such as taste or smell stop working, it's the eyes that best protect us from danger.

Cold viruses hit on average three or four times a year. When people catch cold they feel terribly tired and their sense of smell and taste deteriorates. As a result, it is suddenly no longer possible for us to smell rotten food. Smell is a genetically predetermined program. It used to be essential for survival, as the only possible way to distinguish what was edible from what was inedible was through smell. If the sense of smell stops working, the eyes need to take over, both in looking for mould and other traces as well as in reading the small print of the expiry date.

It may sound strange at first, but in addition to the sense of taste, the eyes also play a major role in deciding whether something tastes good or not. In contrast to the other senses, the sense of taste is very weak: while it is possible for us to distinguish thousands of colours with our eyes, we have the ability to distinguish only five flavours: sweet, sour, salty, bitter and umami, which roughly translates to meaty, a natural flavour enhancer, which is found especially in tomatoes, cheese, and meat. But as already mentioned, the sense of taste does not only rely on the tongue, but also on the eyes. For example, yellow, orange, and especially red food is considered sweeter than food of other colours. Even professional wine connoisseurs have been fooled in the past. When French researchers offered them white wine dyed with red food colouring, nine out of ten professionals could not distinguish it from ordinary red wine.

The sense of sight plays a decisive role in the magic of the first moment. Gestures, facial expressions, and body language make up a large part of the overall impression. Within fractions of a second, people decide whether they find someone attractive or not. It is only getting to know each other better that other senses - in particular the sense of smell - have a role.

Millions of people all over the world face problems with their hearing. Only very few of them make use of the currently existing technical possibilities in order to improve the situation. For these people, a conversation in a large group may become a word salad, and music just a blend of noises. There are also many dangersfor these people as they can no longer hear cars honk, police sirens, or the whistle of a water kettle. At this point, the eyes must take over – in traffic, in the household, in free time.

Blind people also compensate for their handicap with other senses. For example, with intensive training, they can use their sense of hearing to orient themselves in space or their sense of smell to recognise people and places.

Formerly seeing people who have lost their sight because of illness or an accident can remember colours for the rest of their lives. People who have been blind from birth have no proper idea of colours, but they still understand the meaning of light and dark, of bright and dull.