TOG is the brand for basic single vision lenses and bifocal lenses
Basic single vision lens is an optical lens with one single corrective value either for myopia (nearsightedness), hyperopia (farsightedness), or astigmatism
Bifocal lens consists of two distinct areas; the top area is for seeing far while the bottom area is for up close vision like reading. Bifocal lens is used mainly to help people who have hyperopia that occurs with advanced age usually for people who are 40 years old and above.
