order to carry out a vision task. The following table gives several examples: Required visual acuity Vision task Visual acuity 0,8 Reading travel timetables Visual acuity 0,7 Reading a telephone directory [...] acuity 0,1 Orientation outdoors As the table shows, a very clear distinction must be made between the different vision tasks. So it is not surprising that a special magnifying vision aid is usually required [...] aids are able to compensate for the impaired vision by magnifying the images on the retina. Before a suitable magnifying vision aid can be selected, it is necessary to find out what the magnification