There's theories, but no proof as to the effect on fish...
There is proof though, that there are no advantages to having bubbles in a saltwater tank and there are also obvious disavantages...
But another theory is that the air bubbles accumulate in the fish and slowly build in it's bloodstream and eventually coming to a stop behind the fish's eye and building up there. Many fish get air bubbles behind their eye and it looks like pop eye, but nobody can be 100% sure it's because of the air bubbles in a tank...
This is referring to intentionally added air stones and air lines.
The micro bubbles that you see if you have to look really really hard, are in everybody's tanks and are of no consequence.