12.9 Basketball-sized eyes

[Left] The caption reads: "Colossal squid corneas—relatively small parts of the animal's basketball-size eyes (file picture). Photograph by Marty Melville, Getty Images." - National Geographic Daily News (3/15/2012)

This is incorrect, both appear to be the crystalline lens, not the cornea at all.

The colossal squid (Mesonychoteuthis hamiltoni) has basketball-sized eyes - "10.6-inch-wide", and someone is trying to figure out why eyeballs of this size are needed to see at an depth of the ocean where it is essentially pitch-dark.

The answer, according to the report seems:

"The team's models [developed by Dan-Eric Nilsson et al at Sweden's Lund University] revealed that, what the colossal and giant squid's supersize pupils and retinas lacked in close-up vision they made up for with extreme farsightedness. The cephalopods are fine-tuned to spot very large objects at a distance—such as the sperm whales that prey on the squid.

"Still, no matter how large the eye, or how big the object being seen, darkness presents a visual problem.

"With their great light-gathering capacity, squid eyes are able to detect even a faint glow the equivalent of a football field away, the study found.

"Not coincidentally, when a sperm whale is on the move, it disturbs tiny bioluminescent life-forms, creating a faintly glowing trail in the whale's wake—and giving squid an unintentional warning sign."

Hmm... the squids "lacked in close-up vision they made up for with extreme farsightedness"?

To spot tiny bioluminescence a football field away, emmetropic vision, i.e., 20/20 or better, is of course needed. If they are extremely farsighted, then accommodation is required, and if they don't have "close-up vision", then all bets are off. It'll be blurry as heck...

12.8 Farewell, Mr Spock?

News today (see here):

Brain scans of NASA astronauts who were in space for more than a month revealed potentially serious abnormalities that could set back plans for longer deep space missions, according to a US study published Tuesday.

Researchers from The University of Texas Medical School in Houston scanned the eyes and brains of 27 astronauts who had spent an average of 108 days in space, either on space shuttle missions or aboard the International Space Station.

They found that those who spent more than a month in space were more likely to suffer from intracranial hypertension -- a potentially serious condition that occurs when pressure builds within the skull.

The symptoms included excess cerebral-spinal fluid around the optic nerve in 33 percent of the astronauts studied, while a fifth showed a flattening of the back of the eyeball, which affects the ability to focus, research published in the journal Radiology showed.

OK, what about female astronauts?