Where do I start?

I am looking for a book or books that will give me information on the
following:

The mathematics of eyeglass prescriptions, including -

The "prime focus" distance and the expected range ("depth of field" in
photography) at various light levels surrounding the prime focus. I would
expect this to be given as a percent or fraction of the prime focus
distance.

Variation of "depth of field" related to light levels - mid day sunshine
to light from a full moon, for example.

The 'assumed' distances commonly used for prescribing "reading glasses",
"short range?", and "far distance" - as for driving a vehicle.

I have a good background in both photographic technology and physics
research technology - and very little in either human health or organic
bio-chemistry.

I have many chemical sensitivities and a very few "allergies", and some of
my reactions to changes in environment (air and/ or ingested foods)
include significant changes in the distance at which my eyes have a sharp
and clear focus, even in bright daylight.

I am a 'senior' who had excellent vision for most of my life, until the
onset of my environmental sensitivities. Present age, mid 70's.

Ben F.

In article <h3kk26$a0b$(E-Mail Removed)>,
(E-Mail Removed) (Ben Fullerton) wrote:

> I am looking for a book or books that will give me information on the
> following:
>
> The mathematics of eyeglass prescriptions, including -
>
> The "prime focus" distance and the expected range ("depth of field" in
> photography) at various light levels surrounding the prime focus. I would
> expect this to be given as a percent or fraction of the prime focus
> distance.
>
> Variation of "depth of field" related to light levels - mid day sunshine
> to light from a full moon, for example.
>
> The 'assumed' distances commonly used for prescribing "reading glasses",
> "short range?", and "far distance" - as for driving a vehicle.
>
> I have a good background in both photographic technology and physics
> research technology - and very little in either human health or organic
> bio-chemistry.
>
> I have many chemical sensitivities and a very few "allergies", and some of
> my reactions to changes in environment (air and/ or ingested foods)
> include significant changes in the distance at which my eyes have a sharp
> and clear focus, even in bright daylight.
>
> I am a 'senior' who had excellent vision for most of my life, until the
> onset of my environmental sensitivities. Present age, mid 70's.
>
> Ben F.

There is nothing magic about spectacle lenses. I have not looked, but I
will bet that Wikipedia would have a good introduction to optometry.

As for optics, I would recommend the old standby Fundamentals of Optics
by Jenkins and White. I still refer it occasionally in preference to
Born and Wolf.

Bill

--
Most people go to college to get their missing high school education.

On Jul 15, 9:03*am, benfnos...@chebucto.ns.ca (Ben Fullerton) wrote:
> I am looking for a book or books that will give me information on the
> following:
>
> The mathematics of eyeglass prescriptions, including -

It is the same as the mathematics of optics. Any optics text will
do. You could look in your local library for a text on ophthalmic
optics, don't know if you would find one outside of a medical/
optometry/optician school library.


>
> The "prime focus" distance and the expected range ("depth of field" in
> photography) at various light levels surrounding the prime focus. I would
> expect this to be given as a percent or fraction of the prime focus
> distance.

The depth of field will depend upon the pupil size and internal eye
aberrations. Optical equations are the same ones used in photography
with regard to the pupil, eye aberrations are an uncontrolled
varible. Pupil size will depend upon eye colour, light level,
emotional state and age.


> Variation of "depth of field" related to light levels - mid day sunshine
> to light from a full moon, for example.
>
> The 'assumed' distances commonly used for prescribing "reading glasses",
> "short range?", and "far distance" - as for driving a vehicle.

Standard near acuity charts are set for 40cm (16 inches). Prescribing
will be based on the distance the patient actually uses. That
distance will vary with task and arm length -- quilters and decoy
carvers may use 12 inches, computer users may use 22 inches, cello
players may use 30 inches.

Distance testing is done at about 20ft, depending on the examiner's
office size. I use a mirror system in my office that gives a
effective test distance of 23 ft.


> I have a good background in both photographic technology and physics
> research technology - and very little in either human health or organic
> bio-chemistry.
>
> I have many chemical sensitivities and a very few "allergies", and some of
> my reactions to changes in environment (air and/ or ingested foods)
> include significant changes in the distance at which my eyes have a sharp
> and clear focus, even in bright daylight.

Don't look to optics for an explanation of your varible vision, tear
quality and pupil size may be the issue.


Judy

Ben,

You may have interest in this text:

http://archopht.ama-assn.org/cgi/con...ract/123/5/712

Good primer on many of the topics you reference....

Happy hunting!

Neil Brooks ((E-Mail Removed)) wrote:
: Ben,

: You may have interest in this text:

: http://archopht.ama-assn.org/cgi/con...ract/123/5/712

: Good primer on many of the topics you reference....

: Happy hunting!

I want to say "THANK YOU" to you AND others who responded to my questions.

I now have a lot of "homework" to do - and may be back if I have
difficulty understanding some of the more technical or medical details.

I am to pick up a new pair of "driving glasses" this week - I requested
bifocals with "distant" for the main lenses and about 8 or 10 ft. for the
closer detail part of the lenses.

If all is well with these, I will be following up with new "reading
glasses" - after taking some time to convince the optician that I want the
prime focus at 18 to 20 inches, NOT the 12 to 14 in that they wanted me to
accept. (OK after they checked with the doctor who did the testing, and
was willing to accept my requested distances.)

Ben F.