Changes

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It's happened to me, and like as not it has or will happen to you, too. I mean the receipt of certain little numerical results, with a positive or negative before them to prove the correction needed to my vision to make me see with the intended clarity and normality. I've had that gizmo that photos the back of my eye to check for diabetes and other problems, I've had different tests to check the pressure inside my eye, and I've come away with glasses I don't need to wear all the time, but certainly benefit from on holiday, or when watching TV or a cinema or theatre production. And above and beyond that I've stared at – and got wrong – the simple, seemingly ageless test, of various letters in various configurations that diminish in size, to prove to the relevant scientist at what stage things get blurry for me. Of course it's not ageless, but the scientific progress that led to it, the changes other people made to it, and the cultural impact it's had are all on these eye-opening small pages.