The Valsalva Maneuver has many applications and benefits when used correctly. When misused due to a prolonged or forceful application it can have several drawbacks also.
PADI always list the issue they consider primary to divers being the rupture of The Round Window but there can be more adverse effects.
If you ever see a diver attempting forceful Valsalva address the issue and help them work on their equilisation technique or underlying issues that may be causing them to feel they need to forcefully equalise.
Interested in physiology? Why not join one of my upcoming Emergency First Response Instructor programs.