The types of lenses you choose depends on whether you want your glasses to suit all activities or a single activity such as viewing a computer screen or reading only.
single vision lenses
If you’re under the age of 45 and need prescription glasses, single vision lenses may be sufficient enough for your visual requirements. Single vision lenses have the same lens power over the whole surface of the lens and up until this age are generally good for all distances. If you’re over 45 then they may only be good for reading and not long distance.
progressive (multifocal) lenses
If you’re over 45 you probably require progressive lenses which provide a gradual change in lens power from the top of the lens for distance, to the middle of the lens for intermediate or computer distance, down to the bottom of the lens for reading. Progressive lenses have the advantage of being able to see all distances without taking your glasses on and off.