Snapchat are about to launch sunglasses that capture video of what you see.

Your brain already does that.

Many of us think visually. We see ourselves in our experiences. We recall memories this way; in our “mind’s eye”. We even create imagined futures by running video or slide shows of what might happen. Our imagination is cool.

If we start replacing the need to do this because technology does it for us, might we evolve to lose the ability?

Evolution of course takes time, but there is already evidence that more people are becoming nearsighted because of recent changes in patterns of behaviour. A new paper published in the journal Ophthalmology looks at worldwide trends in myopia (nearsightedness) by doing a meta-analysis of 145 studies involving 2.1 million total participants. It predicts that by the year 2050, 4.8 billion people will be nearsighted. That’s 49.8 percent of the world’s population. The theory is that this is because of increased close work in the office, use of handheld devices and because less time is spent outdoors.

So what next? No need to visually recall our experiences; just download what we saw from our sunglasses?

Now that’s a dark thought to dim the brightness of anyone’s day.