The Eyes Almost Have It

March 17, 2013 | By More

A closeup of a human eye reveals that the pupil is almost a perfect circle.

Humans, like other vertebrates that are mainly active during the daytime, have round pupils that are designed to be effective in bright light. Nocturnal animals, meanwhile, have slit pupils to protect their big lenses and sensitive retinas, which allow them to hunt during the night.

But pupil shapes go beyond just round and slit. Some vertebrates’ pupils are shaped like a heart or a crescent, while others’ are shaped like a keyhole.

Associated press writer for Human Rights Observers –


Category: Health and Fitness

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