I've temporarily mitigated this using electronic heat shrink/thermal fit tubing. Though that works pretty well, heat shrink isn't designed for long term skin exposure with sweat and body oils, so I should replace that soon, or hopefully find a better long term solution.

The glasses themselves were made in 1988, so replacement parts are basically out of the question.

Any ideas?

Ear pieces are replacable:

https://www.amazon.com/dp/B09YM8PZXM

Interesting, good to know. I almost wanted to say you're wrong, as these glasses were made in 1988, so the early model spring loaded earpiece hinges are no longer manufactured, but your link refers specifically to the earpiece tips, not the entire earpieces.

Thank you for the advice, I saved your comment and link for future reference. 👍

This was my first thought. An optical store would probably also have them.