Latitude Affects Human Eye Size

People living near the Earth’s poles, where days are often short and light often low, have larger eyes and visual cortices than those closer to the equator.

Written byJef Akst

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As has been found in some bird and primate species, human eye and visual system sizes vary with the levels of ambient light in a given environment, according to a study published yesterday (July 26) in Biology Letters. Near the Earth’s poles, where average day length and light levels decrease, people have evolved larger orbital volumes, which are known to correspond to larger eyeballs and visual cortex volumes. Visual acuity, however, does not vary among human populations by latitude, suggesting that the changes in ocular size exactly compensate for the lower light levels to maintain an average visual performance.

While a similar relationship between low light levels and visual system size is well documented in birds and non-human primates, which are active at dawn and ...

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Meet the Author

Jef Akst
Jef (an unusual nickname for Jennifer) got her master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses. After four years of diving off the Gulf Coast of Tampa and performing behavioral experiments at the Tennessee Aquarium in Chattanooga, she left research to pursue a career in science writing. As The Scientist's managing editor, Jef edited features and oversaw the production of the TS Digest and quarterly print magazine. In 2022, her feature on uterus transplantation earned first place in the trade category of the Awards for Excellence in Health Care Journalism. She is a member of the National Association of Science Writers.
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