Like a Fish Out of Water?

Last night, as I was trying to fall asleep, I started thinking about something I saw on a TV show I had just watched. The show was on the Discovery Channel and this lady had looked underwater and clearly seen sharks. This is something I just don't understand. How can you see such detail underwater without goggles? I have thought about this before and the only thing I can come up with is salt water. I am in the pool all the time and without goggles you can see shapes (which would explain the sharks), but you can't see details.

This is my possible theory: Maybe you can see more detail in salt water than you can in fresh/pool water. People's eyes are covered by a salty liquid. I know for a fact that chlorine affects your eyes. If you keep your eyes open underwater in a pool for too long, your eyes will get fuzzy and you'll see rainbows around lights and such. Trust me. I also know from experience that underwater in a freshwater lake you can see shapes and colors, but no details. However, I haven't spent much time underwater in the ocean recently, and I don't plan on doing so anytime soon. So maybe, because our eyes are salty we can see more detail under salty water. Maybe the mixture of the freshwater and the salty liquid of your eyes creates an estuary like anomaly. That could cause the eyes to blur and make it hard to see. On the other side of things, maybe saltwater mixing with the salty eye fluid does...something different.

I first really started thinking about this after I watched Poseidon. The characters spend quite a bit of time underwater motioning to each other, reading signs, doing whatever they have to to find their way out of the overturned ship. Kurt Russell's character even sacrifices himself to shut off the propeller blades. When he sees that the OFF button is broken, he flips a different switch to make the blades to spin the reverse direction, which allows the others to throw stuff into the blades and blow them up...blah blah blah. I don't see how this is possible. I realize it is a movie and fictional (it might be based on a true story actually), but it just makes me think. How did Russell's character see what the switches and buttons are for? He couldn't have been able to read the labels. Maybe saltwater does allow you to see better. I'll have to test this out someday.