Deep Sea Fish Has Eyesight Similar to Humans

A deep sea fish,  called the anglemouth or Cyclothone microdon,has eyesight similar to a middle aged human adult. The fish is found at a depth of 200 to 500 meters.

Tony Kuhar, a PhD student from University of Western Australia, who studied the fish said the eyes had about 69,000 photoreceptors per square millimetre.

"That sounds like a lot, but if you compare it to fish like, there's a specific myctophid fish that lives at that depth also, they have something around the number of two million [photoreceptors],"  Kuhar said, reports Phys.org.

These fish have smaller eyes compared to other fish who generally have bigger eyes to let in more light.

"But that doesn't mean that they can't see anything," he says.

"Their eyes can probably see as well as a middle-aged human being can.

"I wouldn't say 20/20 vision, probably a little bit worse than that, but not really requiring glasses as such."

 C, microdon is a very common species on earth.

"They inhabit zones of the ocean like the mesopelagic zone where it is completly dark, there's no natural light, but other other organisms give off what they call bioluminescent point light, so little flashes of light in the distance or close by," he said.

"They would be able to pick that green flash up."

As the fish develops it loses the ability to see in light and color, hence, it migrates deep down as it gets older

"They lose the cone part of the retina, so they lose all the cones and they're just left with the rod parts, which is what we use to help us with low-light vision."

He says that the brain part of the fish that controls vision is very developed and it relies more on its vision for prey and avoid predators.

The research was presented last month at the UWA Oceans Institute's Oceans Community.