On 08/06/2021 03:58, Joey wrote:


"Steve Walker" wrote in message
...
On 07/06/2021 21:02, Joey wrote:


"Jeff Layman" wrote in message
...
On 07/06/2021 00:48, Dave Plowman (News) wrote:
In article ,
newshound wrote:
I have the bottom of mine about 12 inches above the desk, so the tops
are about level with the top of my head. But although I use varifocals
elsewhere, I have dedicated single focus "computer" glasses, IIRC +1.5
on my infinity prescription.

Same here. Need more powerful ones for reading, though.

I also require glasses for reading small print (moderate
long-sightedness - +2.5D glasses). I really dislike wearing them because
apart from making the print clearer, they also magnify it. I can't get
my head round whether or not this is solely a consequence of the lenses
correcting the long-sightedness being convex, or it's something else.
Why is it not possible to correct the focal deficiency without
magnification?

As an aside, does anyone else feel that an eye-test where you are asked
if different lenses are clearer or not isn't very scientific?

There isnt any other way to do it.

There is - an Autorefractor.

I hadn't heard of that. Thanks for pointing it out.

It doesnt replace what he doesnt like.
https://en.wikipedia.org/wiki/Autorefractor#Uses

The conclusions stated under "Retinoscopy" in that Wiki are based on old
papers from about 15 years ago. Even the stated "recent studies..."
references papers from 2006 and 2007.

If you look at ref 2, which is from 2005
(https://pubmed.ncbi.nlm.nih.gov/15630406/), at the bottom of the
paper is a list headed "Similar articles". The second paper is from
2019. and if you also look at the "Cited by" heading you will find
papers from 2018 - 2021. I had a look at all the conclusions in these
recent papers, and it seems to me the general view was that modern
automatic methods give a satisfactory result, acceptably similar to
clinical retinoscopy in most cases.

If I do a self-test for reading strength (eg at
https://www.readingglassesetc.com/pages/reading-lens-guide/reading-glasses-strength-and-reading-test.html),
I can read down to the smallest line (+1.25D) without problem. Why then
does my optician prescribe +2.75D glasses for me? I assume it's because
of the responses I gave during the eye test, which is entirely
subjective. I don't have an issue with corrective lenses for astigmatic
issues, but I find the "solution" for long-sightedness less than
satisfactory. Do those with short-sightedness have the same problem with
their prescribed glasses?

--

Jeff