Those who wear bifocals may find that the reading portion of their lenses does not provide good focusing ability for medium-range tasks. With this in mind, hobbyists, recreationalists, and workers who require a prescription suited to the particular distance requirements of their pursuits may want a third prescription that is different from the ones needed for reading and distance viewing. This is where trifocals come into play. The distance prescription at the top of the lens allows the wearer to see clearly from about 5 feet to infinity, while the reading prescription enables him or her to read up close. The in-between segment can be formulated for a specific purpose in the 1.5- to 4-foot range. Trifocals are generally prescribed for individuals with advanced presbyopia. Presbyopia, from the Latin words for "aging eyes," is a normal loss of visual accommodation. As individuals move into their 40s, most begin to notice problems seeing near objects – especially small print. “Progressive lenses” provide three viewing prescriptions without telltale dividing lines between prescriptions.