When your baby first opens their eyes what do they see?

We now know exactly what a newborn can see and for the first time it can be recreated, experts say.

Babies who are only a few days old can perceive faces and may be able to read emotional expressions at about 30cm, according to a Norwegian and Swedish study.

The ruler-length distance is about the same distance between a mother breastfeeding or bottle-feeding their baby.

That means when I locked eyes with my baby when he was first born, perhaps he could see my teary eyes.

This image shows how a newborn perceives expressions. Image courtesy of Olof von Hofsten/EclipseOptics and Bruno Laeng/UiO

The researchers mixed the information already known about infant’s visual world with mathematics and new technology.

“Previously, when researchers have tried to estimate exactly what a newborn baby sees, they have invariably used still photos.

“But the real world is dynamic. Our idea was to use images in motion," says Professor Svein Magnussen from University of Oslo.

The professor wanted to research it about 15 years ago but it didn’t come to fruition until recently.

“Back then we had neither the equipment nor the technical competence to test our idea,” he said.

What was already known about babies visual perception came from research mainly conducted in the 1980s.

Back then, tests were conducted by presenting a figure against a grey background, which caused the infant to direct its gaze towards the figure.

Researchers say the distance is an important one for picking up mother's signals. Image via iStock

"By choosing a certain stripe width and frequency, the field would appear uniformly grey, and the child would not direct its gaze towards it.

“Changing the width and frequency to make up figures, made it possible to determine the exact level of contrast and spatial resolution needed to make the infant direct its gaze towards the figure," Magnussen said.

So to modernise the test, the researchers used video recordings of happy, angry, and surprised faces.

They combined the test with some complicated mathematics to come up with photo images that represent exactly how a baby sees the world.

Researchers haven’t yet worked out what a baby can understand about the visual world their seeing but they think the distance isn't a chance measurement.

"It's an important distance for a baby to be picking up mothers signals,” Professor Tim Brennen told Reuters.

"It’s not by chance that the results were much better at 30cm than 60 or 120,” he said.

Researchers from the University of Uppsala along with experts from Eclipse Optics in Sweden joined the University of Oslo for the study.