I got my first pair of varifocals a few months ago. When I put them on I felt I was swimming in a sea of blur and I was tempted to abandon the experiment.  Nathaniel said, don’t worry, in a few days you’ll be used to them and the world will look good again.

He was right.  My brain adjusted comprehensively and my new eyesight quickly became the new normal.  On a glorious walk along the South Downs Way yesterday, for example, I almost never noticed that the focussed fraction of my field of vision is half what it was a year ago.

Your first thought may be pleasure at how easily our brains adjust, but your second should be one of horror.  How diabolically our brains disguise our declining powers!  My visual input is half what it was a year ago, and I don’t notice.  It’s probably a tenth what it was when I as a teenager, and I don’t notice that either.  It’s a safe bet the power of my thought has diminished too.  As the engine slows down, occasionally there are puzzling artifacts out there in the periphery, but for the most part, we don’t notice.

[11 April 2016]