On 07/06/2021 13:24, Dave Plowman (News) wrote:
In article ,
newshound wrote:
At my more advanced age (70 +) I certainly feel that my "prescription"
can sometimes vary through the day. I'm not sure whether this is because
it actually does, or whether it is an effect of continually reducing
accomodation (so that I notice the effect more).

Think at 70, your eyes are likely pretty well fixed focus.

My optician, a couple of years ago, initially gave me slightly more plus
than needed for infinity. Not something you'd notice in the consulting
room. But did when driving. His answer was it was a compromise most liked.
I didn't.

Certainly when I was a short sighted kid they used to under-correct for
infinity, I suspect based on the theory that your eyes would "try
harder" and otherwise deteriorate more rapidly. I always found that
slightly irritating. For my "bike" test (silver numberplate days of
course) I could not completely read the plate at the requested distance
(which was more like 35 yards than 25), but fortunately a couple of
paces was all I needed.