If you can't tell you these four celebrities are behind the dots, it could be a sign you are colour blind.
Opticians claim the bizarre test - a tweak on one commonly used in eye clinics - can show whether you are one of millions to have the condition.
The Ishihara plate test, as it is officially known, normally hides numbers behind the dots and asks patients to try and identify them. Those who struggle are often told they have red-green colour deficiencies.
But in a twist of the century-old method created by a Japanese professor, Optical Express have instead hidden four spectacle-wearing A-listers.
And if you're struggling to recognise who the famous faces are, it may help to lean back and squint.
Stephen Hannan, clinical services director at Optical Express, said the test was created to boost the profile of Colour Blind Awareness Day.
He said: 'Although a harmless condition, we want to raise awareness of just how common colour deficiency can be and stop it being overlooked in schools, the workplace and everyday life.
'Removing the stigma and providing greater information on the condition will help those who struggle to distinguish between certain colours lead a normal and unrestricted life.
'Typical vision tests don't check for colour vision deficiency.
'However, if you are struggling to see the famous faces in our Ishihara test and think you may be colour blind, your optometrist can take you through a longer version of the Ishihara test or a colour arrangement task to diagnose the severity of your case.'
Figures suggest there are almost three million Britons living with the condition, even though scores are unaware they have it.
Most patients struggle to differentiate between certain colours from birth, but, in rare cases, it can develop later in life.
It is more common in men, affecting around one in 12 men compared to one in 200 women, as it is often passed on by parents through the X chromosome.
Being colour blind does not have a direct impact on health – and most people gently adapt to the condition over time.
Notable celebrities such as Prince William, Keanu Reeves and Eddie Redmayne have confessed to having a colour vision deficiency.
Most patients find it hard to distinguish between red and green, and blue and yellow as colours often appear much duller.
Opticians say this makes it hard for patients to tell the difference between shades of purple, red, orange, yellow, brown and green.
Dr Shinobu Ishihara, a professor at the University of Tokyo, devised the idea to test for red-green colour deficiencies in 1917.
His test, named after him, is now widely used by opticians – including ones working in the NHS - as one of the main ways of diagnosing patients with the condition.
It is not part of the routine eye test given by opticians on the health service in the UK, which patients should have every two years.
But patients concerned about their vision can ask to have the test, in which they will have to identify numbers contained within images made up of different coloured dots, if they wish.
It comes after the Department for Education in the UK recognised colour blindness as a Special Education Need and a disability two years ago.
This article has been adapted from its original source.
© Associated Newspapers Ltd.