What's the problem with the LED, does the liquid filling cause TIR off the watch-face/external air boundary? If that's not the problem, you could try side-mount

What's the problem with the LED, does the liquid filling cause TIR off the watch-face/external air boundary? If that's not the problem, you could try side-mounting the led, as here: https://www.instructables.com/id/Watch-LED-Light-Mod/ https://www.instructables.com/id/Watch-LED-Light-Mod/ Does the oil leak out of the buttons when they're pressed? How about the buzzer? I think it's attached to the back of the watch so shouldn't be affected too much? Someone mentioned improved readability. I assume underwater that is definitely the case, as you no longer get TIR reflections off the back of the watch-face/internal air boundary at steep angles, but how is readability affected in air?