One more thing...
A bifocal lens is a more antiquated solution to combine distance vision and near vision. There is a small area at the bottom of the lens that is separated by a line from the rest of the lens. You can compare it to a ‘half-moon’ that is lying on its curved side. This area of the lens is used for reading. The lens is less aesthetically pleasing due to the visible line that separates the half-moon from the rest. The lens provides good vision for distance and near vision; however this lens does not contain any refraction for intermediate distances. Therefore, it is harder to see objects clearly that are 50 to 150 cm away.
The plastic, bifocal lenses are named Orgalit®, and the glass or mineral lenses have the name Optolux®.
With these lenses, you can choose various indexes, materials and coatings. Different treatments can also be added: color, photochromic, polarized, eye care or driving.