In Real Life, it's very difficult to see underwater without wearing a facemask or goggles. Even things that are less than a foot away from your face come across as vague, indistinct blurs. This is because air and water have different refractive indices, and our eyes have adapted to focusing the light from the outside air through the (mostly watery) humors inside the eye onto the retina. When we replace air with water, the eye cannot physically adapt to different refraction angles and starts focusing the light far behind the retina, making all images blurry, at best. Read more about it here.
On top of that, depending on what's in the water around your head, opening your eyes can be anything from irritating to excruciating, and in the case of extremely contaminated water, may result in a nasty infection that'll lose you your eye.
This is not the case in TV Land, however, where characters have the same crystal-clear visibility underwater as a camera lens, and can routinely read individual letters from long distances with their bare eyes.
A subtrope of Water Is Air.
- British comic character Fishboy (appearing in the weekly anthology Buster) was an amphibious Wild Child who also didn't need goggles underwater.
- In Atlantis: The Lost Empire, Milo Thatch reads ancient Atlantean underwater inscriptions with glasses on. Note that reading them with his glasses off could actually be possible—extremely shortsighted people can see more or less normal underwater, due to their eye's skewed refraction.
- Inversion with Abe Sapien in the Hellboy films: He requires goggles (or in the second film, contact lenses) to put water around his eyes to see clearly through air.
- Galen in Dragonslayer is able to determine Valerian's real sex underwater, in a fairly murky pond, from about 5 feet away.
- At the end of Mindhunters, the heroine and killer wind up in an underwater gunfight, in which they can clearly see one another's actions from a few yards apart. The heroine even mouths insults at her opponent, who gives her dirty looks in response.
- Will in Pirates of the Caribbean: Dead Man's Chest has no problem opening his eye underwater and seeing the attacking Kraken.
- The characters in Poseidon navigate a convoluted passage that's flooded with salt water, very obviously using flashlights to look where they're going and keep track of one another.
- The classic adventure novel The Coral Island by R.M. Ballantyne describes the characters swimming underwater and looking around at the marine life, which they can see clearly.
- In Warrior Cats, Flametail is able to see clearly underwater as he drowns.
- On Lost, nobody ever has problems seeing things underwater, from Kate and Sawyer finding the suitcase full of guns in Season 1, to Nikki and Paolo finding their bag of diamonds in the same pond in Season 3, to following Richard Alpert underwater to the bomb in Season 5.
- If a game features water, it's more likely to use this trope than not, so aversions:
- Half-Life 2 has water that you can only see a few feet out from you in while swimming, but that's only a fog that represents mud, pollution and other particles in the water. The underwater view is otherwise completely clear. However, Episode Two subverts this trope by adding a blur effect while underwater. And of course, see Half-Life's entry on this page for the debate about how much of a Justified Trope this might or might not be.
- In Metroid Prime, your view is obscured underwater even though Samus already has a face mask. The powerup that lets you move freely in water also upgrades your visor so you can see freely, as well.
- In The Elder Scrolls III: Morrowind, unless you swim at exactly the right height, you can't see far.
- In Minecraft, in addition to the general blue overlay and particles floating around, water gets darker the deeper down you go, making it impossible to see more than a few blocks down. There are ways to make it easier to see under water; the Respiration enchantment for headgear partially removes the blue overlay and the Night Vision potion helps with the darkness. Respiration III plus a Night Vision potion allows the player to see just as well under water as on land.
- However, Starting in Version 1.13, underwater vision improves the longer the player is underwater, even without enchantments or potions. The update also changed light to spread the same way as on land, compared to being three times dimmer underwater.
- This Mias and Elle comic finds salt water in the eyes to not be very romantic.
- Many semi-aquatic animals have a transparent second eyelid that corrects for refraction and allows them to see clearly underwater.
- The four-eyed fish, which spends its life at the surface of ponds and streams, has eyeballs with double pupils: an upper one for seeing in air, and a lower one for seeing clearly in water.
- People with nearsighted vision can see better underwater than people with 20/20 vision, due to the way the water magnifies and refracts light.
- These people can not only hold their breath a very long time, but they are either adapted or have learned from childhood to compensate for the difference in refraction to see very well underwater. They spend a lot of time diving!
- Loch Ness is an aversion, which makes the Loch Ness Monster both more and less plausible. The water of the loch is extremely dark, which makes exploration difficult and allows people to imagine all sorts of things living undiscovered in its depths. On the other hand, the darkness of the water results in less vegetation, which results in fewer fish feeding on the vegetation, which results in fewer predatory fish feeding on them. It's thus very unlikely that some kind of leftover dinosaur or something could have survived there.