single vision means a person needs one prescription in their lenses only. The lenses can have matching prescriptions or different ones. These can consist of a plus or minus prescription, or even no prescription in one eye, while the other has either a plus or a minus prescription, or both.
Single vision lenses refer to lenses that have only one use, either to see objects in the distance, or for reading (Reading glasses). While bifocals/progressives are a type of prescription eyeglasses that can be used to correct both near and farsightedness.Hope this helpful.