Is it true that your eyeballs stay the same size from birth?

Untitled by tee-dot, on FlickrAww, look at those big blue eyes – aren’t they adorable? There’s no denying that a baby’s eyes are one reason why we find them so cute. And, let’s face it, with all the crying and pooping, they need something to help make us fall in love with them.

So given the relatively large size of a baby’s eyes, it’s not surprising that many people say that a baby’s eyes are full size. It is, however, not true – a child’s eyes grow just like the rest of their body does.

The size and growth of human eyes has been previously studied by several researchers. Going right back to research published in 1940, researchers first charted how human eyes grew over time. Although the research is very old, the scientists did a thorough job – meticulously measuring and weighing eyeballs taken from cadavers.

The informative graph below shows how eyes grow throughout life. The lines show the size of the eyeball (on the vertical axis) over time (horizontal axis).

They discovered that that eyes grow fastest in the first year of life and then slow down while the rest of the body catches up. At adolescence (on the right hand side of the graph) there is another growth spurt. Thereafter, the size of the eyeball pretty much stays the same for the rest of a person’s life.

Growth of the eyeball over time graph

Quite why a baby has such disproportionately large eyes, no one knows. Perhaps it is to help their vision in the early years, or maybe it is to simply make them look irresistibly loveable.

It is however just as well that a baby’s eyes aren’t really full size when born. If they really were full size at birth, then they would appear at least 1.5 times larger than they do. Which would make them look like an alien – and that most definitely wouldn’t be adorable.

Answer by Dr Stu

T. WINGATE TODD, HARRY BEECHER, GUY H. WILLIAMS, & ARTHUR W. TODD (1940). THE WEIGHT AND GROWTH OF THE HUMAN EYEBALL Human Biology, 12 (1), 1-20

Image: tee-dot, on Flickr

Article by Stuart Farrimond

April 30, 2014

Doctor Stu is editor of Guru Magazine. He originally trained as a medical doctor before deciding to branch out into lecturing, writing, editing and science communication. He drinks far too much coffee, eats lots of ice cream and has a bizarre love of keeping fit.
You can check out Doctor Stu’s blog at realdoctorstu.com or his poncy personal website stuartfarrimond.com. Here's his .


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