In article , Clive D. W. Feather
writes
In article , Andrew P Smith
writes
(4) The person has an intermittent eyesight problem that doesn't stop
them playing a game but isn't safe for something like train driving.
For example, temporary blindness in one part of the retina, or
temporary blindness in low light.

But they can see a squash ball whizzing around a brightly lit white
court at 35 mph.........

To continue with this one as an example:
(1) I said "one part of the retina", or "low light"; neither case would
prevent you seeing a brightly lit squash ball in continual motion
relative to your sightlines.


I didn't realise all tube tunnels were lit. If you can see a moving
squash ball then you can see a signal.

(2) If they fail to spot the ball once, the worst they get is a clonk
from it. If they fail to spot a signal or other hazard once, people can
die.


Signal is a red herring, I believe you know all about tripcocks. If the
drivers eye sight is defective then they will be rumbled at the medical
each year and stop driving trains.

Sheesh. Do I have to make the difference any clearer?

When in a hole Clive, stop digging.
--
Andrew
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