What is the possessive form of eyeglasses?

Answer 1

There are two accepted forms for possessive singular nouns ending in s:

Add an apostrophe (') after the existing s at the end of the word: lens'

Add an apostrophe s ('s) after the existing s at the end of the word: lens's

Examples:

Your lens' setting is not correct for that distance.

Your lens's setting is not correct for that distance.

Answer 2

The possessive form for the noun eyeglasses is eyeglasses'.

Example: My eyeglasses' case is in that drawer.

Answer 3

The possessive form is the glasses' lenses.