Modifies a noun

• lens: Your optician will have advised you whether bifocal lenses are a suitable choice for your needs.

• glass: Bifocal glasses can contribute to balance problems for some people.

• spectacle: If you wear bifocal spectacles you end up like a nodding donkey trying to focus on different parts of a screen!

• option: Some frame styles are not suitable for bifocal lenses and, on the website, these do not offer the bifocal option.