0 used to refer to lenses that are divided into two parts. The upper half is for looking at things that are far away and the lower half is for reading or for looking at things that are near: --
This created a giant bifocal system which allowed him to see the blackboard through the right side, then use the left side to write down what he had seen.
It is sometimes also referred to as the bifocal tensor.
This is the first ever recorded use of bifocal technology in the animal world.
It offers pure science as well as bifocal subjects.
The large eyes at the front of the head provide it with the bifocal vision and depth perception it needs to catch prey.
In a creative sense, the bifocal reward is that you are bound by neither.
We have bifocal vision, we have carnivore-type teeth, and we have never developed the multiple stomachs that would enable us to live off grass and to chew the cud.
If, as a consequence of not being able to get bifocal glasses there is a deterioration, then obviously bifocals ought not to have been recommended, but two pairs of glasses.