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:
I need some bifocal sunglasses.
An interesting issue is the extent to which bifocal and varifocal spectacles might be a contributory factor in falls on stairs.
If falls begin shortly after the issue of bifocal spectacles, they should be abandoned and optimal correction ensured for everyday living.
The musical text is similarly bifocal.
You can go and buy bifocal spectacles in the private sector for well over £100.
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.
