A pronoun that could refer to "her glasses" is "theirs."
In English, pronouns like "his" or "hers" are not used to refer specifically to objects like glasses. Instead, possessive pronouns are typically used for objects, such as "its" or "theirs." For example, "She left her glasses on the table. They are hers."
In this case, "they" refers to the glasses, and "hers" is the possessive pronoun indicating ownership.