Huh, the machine must have bust. The one with the LEDs is very good cos it shows very low light-levels sometimes. It sums the patches in a way that clearly shows the blind-spots, so despite being a tad unsure about the low light ones, the averaging really does paint the picture.
A bit of drift, but my AME used to slide the near sight thing down to my nose, and I would go cross-eyed and say, 'custom, on the first day of every...'
"marvelous! you're better than a lot of the young chaps just starting."
Had to fess up eventually, as I needed glasses to fill in the form.