The effect of damage to optical pathways on posture and movement

Of all man's senses, his ability to see is undoubtedly the most important. It is through vision that we derive pleasure from television, movies and ballet, that we can enjoy the convenience of driving a motor vehicle and maintain the ability to protect ourselves from other lethal weapons on our roads. Memory, dreams, imagination, sound, smell and taste all have visual associations. We judge time, in seconds, days or seasons by what we see. Memory in particular is based to a large extent on visual experiences, and those who lose vision can still recall its highlights and understand its meaning. Those who are born blind must have great difficulty in understanding seemingly simple things we take for granted, such as the meaning of light and dark, the concepts of colour, the beauty of sunsets, and the information imparted by various facial expressions. We with vision can observe a small degree of contraction of the orbicularis oris which changes an insulting remark into a humorous one.