Spectacles with standard reading or progressive lenses are generally not ideal for working at the computer because the relevant areas of the lens are not optimised for office work. Reading glasses, for example, only enable optimum vision for a short distance – too short for working at the computer or looking at your desk. With progressive lenses, however, the wearer looks at the monitor through the lower area of the lens and must tilt their head upwards in order to see the screen clearly. Both types of lenses promote an unnatural posture while sitting, potentially causing muscle tension in your back, shoulders and back as well as headaches.