Dear Sean and David
I could find no explicit English reference to the type of
glasses my ophthalmologist and opticien suggesetd to me, but I suppose
these are what you are calling "close to medium" prescription. I have
roughly translated what I read in French.
"Degressive lenses or mid-distance glasses (sometimes called deep field
of vision, or could that be wide field?) allow one to see from close-up
(40 cm) to middle distance (1metre). They have a variable geometry, and
are a complement to progressive lenses. They offer excellent comfort
for work on the computer."
Yes, I think these need the same accurate setting as progressive
glasses. Are these the ones you mean.
The optician suggested a cheaper make than Essilor to save money on two
pairs (but Essilor for the full progressive pair), but I am a little
wary of that. In France they don't seem to deal in Zeiss glasses.
I was having dizzy spells, and after various other tests, it seems this
could be down to reading music and the computer with glasses found in a
Christmas cracker.
Thanks for your advice.
Anthony
Dear Anthony,
I recommend the close to medium prescription for lute playing and this
should differ slightly from a regular reading prescription. When you
next go to get glasses tell them you want reading glasses for a
specific distance. Measure your eyeball to music stand distance before
you go. Have them make their prescription for that distance and
dedicate these for your lute playing. A competent optometrist will make
two adjustments to your prescription: the focus at that distance and
the parallax (the distance from the centers of the lenses changes as
you look at close objects to further objects. In other words, as you
look at closer objects your eyes "cross" and allowance should be made
for this. Of course, the distance decreases for closer objects; at
infinity the centers are the same distance as the centers of your
pupils. It may seem negligible but can be a source of eye strain and
headache if not addressed.)
I don't believe the progressive lenses always take parallax into
account though I might be wrong. I've only recently entered the world
of Needingglassess but have worked in optics for a few years.
Always the optimist,
Sean
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