Two in every 100 people have aphantasia, otherwise known as a 'blind imagination'.

When you close your eyes and try and imagine a beach, what happens?

Can you actually see a beach? Is it clear like a photograph? Can you make out the colour of the sand and the shape of the shoreline?

For a small percentage of people, this is entirely impossible. And I’m one of them.

It wasn’t until very recently, when a Professor of Cognitive and Behavioural Neurology stumbled across what he thought was an “odd” case, that he discovered an estimated two in every 100 people have a “blind mind”.

Professor Adam Zeman met a patient in his mid-60s who had undergone an operation on his heart. He told Zeman that while he had previously enjoyed “imagining the faces of friends and places he’d been”, all of a sudden, after the surgery, he became “unable to summon imagery voluntarily.”

Since this case study, Zeman has heard from over 10,000 people with the condition, now named aphantasia.

People with aphantasia cannot imagine a landscape or the face of a person. They see nothing. Their mind’s eye is effectively blind.

In April of 2016, Blake Ross, creator of the Mozilla Firefox web browser, wrote about living with the condition.

“I have never visualised anything in my entire life…” he writes. “I can’t ‘see’ my father’s face or a bouncing blue ball, my childhood bedroom or the run I went on ten minutes ago. I thought ‘counting sheep’ was a metaphor. I’m 30 years old and I never knew a human could do any of this. And it is blowing my goddamned mind.”

Even in regards to something simpler, like a red triangle, Ross says, “I can’t even understand the question. I can think about the idea of a red triangle. But it’s blackness behind my eyes. Blackness next to my ears. Blackness in every nook and kindle of my brain.”

When it comes to dreams, he overwhelmingly can’t recall them. And when he can “there was no visual or sensory component to them.” It just appears as a list of plot points.

Professor Zeman has explored what causes this abnormality, and thinks there is “something a bit different about [aphantisic people’s] brains, and that there may be a genetic component.” For some, the condition is lifelong. For others, it emerges later in life.

You can test the strength of your mind's eye through online tests such as this one. Some of the questions include:

• Conjure up an image of a friend or relative who you frequently see; how clearly can you see the contours of their face, head, shoulders and body?
• Rate how vivid the colours of that person's clothes look in your mind?
• Visualise a rising sun and look carefully at the details of that mental picture; how clearly do you see that sun rising above the horizon in a hazy sky?

During this test I realised something.

I can barely see any of these things. I know what the colour pink looks like, but I can't evoke the tone in my mind. I cannot close my eyes and see my mother's face. I can understand and perceive the features of an image, but I cannot truly 'see' it.

There are some exceptions. I can see a very hazy image of my bedroom. I am hit with a flash of colour or a shape, but it doesn't hold long enough for me to fully make out what it is. I never see an image in its entirety.

A few things are beginning to make sense. I have terrible spatial awareness. I can't go shopping and judge what would go with something I have at home. I can't tell, even almost, if that lounge will fit in my living room simply by looking at it. I've never understood mindfulness. My mind's eye is sort of...useless.

I also dream almost entirely in feelings. There are no faces or images or distinct places, although sometimes I know instinctively who someone is. I am never, however, left with a picture.

It is endlessly interesting that what I think, and what you think, and what you see, and what I see, may be completely different.

If you want to make contact with other aphantasics, or participate in research, you can follow Sydney Aphantasia Research on Facebook.