When you meet volo at camp, watch his gestures carefully during the surgery conversation - his enthusiasm and wild hand movements are a clear sign this might not be the safest choice. Refusing keeps both your natural eyes and prevents that permanent blue glow effect, plus your companions will actually respect you more for being cautious. The real trade-off comes with the see invisibility effect you're missing, which helps spot hidden enemies within 9 meters that fail their dexterity saves.

If you're planning ahead, keeping volo around camp longer by refusing isn't a bad idea, especially since he's got some useful items for trade. Maybe interesting to note that turning him down keeps your options open for auntie ethel's deal later, though that comes with its own complications around hag interactions. The surgery itself is purely optional, and the game doesn't penalize you narrative-wise for playing it safe with your character's original eyes.

Just remember that while the see invisibility effect is pretty strong for combat encounters, the aesthetic and roleplay elements might matter more depending on your character's story.