What colour do YOU see? This woman's eyes aren't actually blue trends now
What colour would you say this woman's eyes are? Your brain will probably tell you they are blue.
But it has fallen victim to a mind-boggling optical illusion, as it turns out that the model's irises are actually grey.
This is made more obvious when the red filter is removed from the image and a grey bar is placed right next to the eyes.
The trick was shared on TikTok by serial illusionist Dean Jackson, or @beatonthebeeb, who explains how it works.
'Your brain detects the pigment - the grey area around the pupil - and it assumes that the red filter has trapped the blue light,' he said.
What colour would you say this woman's eyes are? Your brain will probably tell you they are blue. But it has fallen victim to an optical illusion, as the model's irises are actually grey
'So it tries to help you out, as your brain should, by putting the blue colour back into the picture for you, and your brain is completely misleading you in the process.'
At the back of the human eye are photoreceptors - cells that respond to the light shining in.
These come in two types, 'rods' or 'cones', and while rods are sensitive to motion and night vision, the cones that are able to detect colour.
Humans have three types of cone cells, and each of these are most sensitive to a particular colour, either red, green or blue.
A red filter only lets through red light, so any other colours should appear as grey or black, including green and blue.
The original image of the woman is in black and white, and it is only when the red filter is placed over the top that the eye colour appears blue.
However, if our brain recognises the context of the image and believes it should appear blue, it can interpret the grey light as