After the age of 45, most people will need reading glasses. However, looking at far distance with these, everything gets blurred. In the progressive glasses, there is a zone in the lower part of the lens, where you naturally look through when reading. In the upper/straight ahead zone of the lens, you have no optical refraction for those who do not need glasses for distance, or the prescription for others. You may keep the glasses on all day, or in situations where this is needed.