You are right to say that "There is certainly debate about whether
NITM is important in the development of axial myopia,"  and that
"there are hints that one is involved with the other".

I goofed in my response. By using caps for "elongation" and
accidentally leaving out a sentence,  I gave the impression that I
support this idea. I don't, at least not yet. The ones who do support
it are some of the "retinal defocus" people.

To quote one of the them on the role of NITM, "We speculate that the
retinal defocus CAUSED BY  (my emphasis) the NITM may act as a trigger
mechanism in the development of myopia" (1) (And of course the
"retinal defocus people" favor the elongation theory).

Based on the quote above, I guess that they reason as follows:

1.    A blurred retinal image causes the eye to elongate
2.    NITM produces a blurred retinal image
3.    Ergo, NITM causes the eye to elongate

Most of the "NITM people", as far as I can tell, don't even mention
elongation.  They only say that if nearwork is prolonged, the lens
takes time to relax its accommodation after ending the near task. The
result is a blurred retinal image. Many or most of them attribute this
to changes in tonic accommodation.

According to the "retinal defocus people", the blurred retinal image
causes the eye to elongate: during nearwork the lens fails to
accommodate sufficiently; the resulting  "lag" of accommodation
triggers a neural process that causes the eye to elongate, so that the
retina is moved backwards to match the focal point.

Wait a minute! you say. It may make sense to say that hyperopic blur,
i.e. from a focal point located behind the retina, might trigger a
mechanism that makes the eye grow longer to match it. But, what happens
in the case of NITM? If, after the nearwork task is ended, the lens
remains somewhat accommodated even when looking at a distance, then the
blur is *myopic*, i.e. from a focal point in *front* of the retina.

How could the two different types  of blur produce the same
effect--cause the eye to elongate?  Theoretically only the blur from
*behind* the retina should trigger this. They can't have it both
ways, you might say.

Oh, but they can! No matter what objection you raise, they've got an
answer. Two, actually.

One is this: A newborn's eye starts out being hyperopic. As it
develops, the hyperopia decreases and tends toward emmetropia, so that
the progression is usually  hyperopia>emmetropia> myopia  (if it goes
that far). I'm trying to remember as much of this as I can, from one
of the major vision journals.

So, the visual control mechanism is so "accustomed" to this
progression, always from hyperopia to emmetropia to myopia, that it
interprets *any* blur as hyperopic blur, no matter where it comes from.
As to the other explanation, this post is already getting too long.

Unlike some posters who cite references that don't actually exist, I
list 6 (below) that I guarantee do exist.

This pseudomyopia/NITM/retinal defocus stuff is a bit complicated, at
least for me. As everyone knows, I'm not too bright, and the proof is
that I propose ideas that *conflict* with what everybody knows about
the eye.

Of course it's good to be skeptical, but you can go too far, like the
scientist in the joke about a flock of sheep. The scientist is driving
in the country with a friend. The friend, a non-scientist, says,
"Look at that flock of sheep. They've just been sheared".
"Well", says the scientist, "they've been sheared on THIS
side".

I'm skeptical about claims that "the purpose of this newsgroup is
to discuss issues related to eye health and vision care from a
scientific viewpoint".

The case for being skeptical about this? Easy. Too many posts like this
one by "Dr" Grant:

"It appears you are a lesbian Nazi with genital
piercings and a penchant for torturing small animals.  ROFLOL"

Does anybody really believe that this crap is appropriate for s.m.v.? I
put Dr in quotes because I know close to a hundred doctors (I work in a
very large hospital/clinic/research institute) and not one of them
comes even *close* to "Dr" Grant for low-class vulgarity. Of course
he really could be a doctor of something, but I'm skeptical.

So, here I go again, with a post about what this forum is supposed to
be about, discussions concerning vision, not ridicule. Of course I will
get some smart-a.s responses, and they will serve precisely to prove my
point.

Actually, I'm sure that most s.m.v.ers are smart, but also modest,
too. I don't check in all the time, but I have never seen a post
about the eye research they do, the papers they have written and
presentations of their work at international conferences.

I have been lurking and posting, off and on, for several years, but
have never mentioned international conferences. I'm doing so now to
differentiate myself from those who want to lump me in with the
weirdos. I prefer not to be associated with *anybody* on this forum

Even though I said above that "I propose ideas that *conflict* with
current knowledge of the eye", there are some people in the research
community, in contrast to s.m.v., who *have*  been somewhat receptive
to my ideas. At the various conferences I have taken part in at least
it's nice to actually discuss vision. Sure, some of them hint that
I'm crazy, but at least they are polite about it.

They don't maliciously twist my words to mean something I never
intended (it happens all the time here) and they don't insult me.  I
meet interesting people too; in Alicante, Spain, two Nobel Prize
winners, David Hubel and Torsten Weisel.

Various papers that I have written have been accepted by the organizing
committees of five international conferences:

University of Missouri at St. Louis, Vision Science Symposium
Sixth International Congress of Eye Research, Alicante, Spain
CLADE Conference, Porto Alegre, Brazil
10th International Myopia Conference, Cambridge, England
CLADE Conference, Santiago, Chile

At St. Louis, Elio Raviola, a noted vision researcher from Harvard, was
on the same program as me. Unfortunately, he left just after finishing
his presentation, so he missed hearing mine :-)

If you're wondering about the acronym CLADE, it's a research
organization dealing with strabismus/muscular imbalance and related
topics.  However, they agreed with me that although my subject is
myopia,  my paper was appropriate for their conferences because a major
part of it deals with the extraocular muscles and their effect on
refraction.

Now, it's s.m.v.-ers turn to tell us all about their accomplishments
in  vision science.   If nobody responds, then what does that suggest?

The trips are nice, and those Brazilian babes!  Ooooooh!!! (they go
topless at the beach, just like in Spain)...OOPS!!!! I'm getting
*way* off topic here! Well, so what? Everybody else does.

One of the advantages of international conferences is this: If I said
to my "significant other", "Hey, I'm going to Brazil, see ya in
a week", you can imagine the response: "You're going WHERE!!!? No
you're NOT!!"  But if I say, "I'm going to Brazil for a vision
conference", no problem!

There is so much viciousness and vulgarity on this forum that, along
with my more technical posts about vision, I sometimes try to mix in a
little entertainment and humor to counterbalance it. Naah, it's not
working-forget it. No more entertainment from me.

But speaking of entertainment, I think Otis and the Bateseians are
essential to s.m.v. They're a perfect target for your hostility, and
how else are you going to display your superiority if you don't have
them as targets? S.m.v. would be a lot duller without them, don't you
agree?

I'm starting to think I should just stick with international
conferences. The travel is nice (money is no problem) and I meet a
better class of people.

--Rich

1.  Ong and Ciufredda, Documenta Ophthalmologica 91: 57-85, 1995
Nearwork-induced transient myopia
----------------------------------------------

(According to the source of these referencees, they deal with
NITM/axial elongation. I haven't read them so I don't know for
sure).

Coleman J, Wuchinich D, Carlin B. Accommodative changes in the axial
dimension of the human eye. In: Gitter KA, Keeney AH, Sarin LK, Meyer
D, eds. Ophthalmic Ultrasound. St. Louis: C.V. Mosby Co., 1969: 134-41.

Storey JK, Rabie EP. Ultrasound- a research tool in the study of
accommodation. Ophthal Physiol Opt 1983; 3: 315 - 20.

Beauchamp R, Mitchell B. Ultrasound measures of vitreous chamber depth
during ocular accommodation. Am J Optom Physiol Opt 1985; 62: 523-32.

Lepper RD, Trier HG. Measurement of accommodative changes in human eyes
by means of a high-resolution ultrasonic system. In: Ossoinig KC, ed.
Ophthalmic Echography, Proceedings of the 10th SIDUO Congress. Doc
Ophthalmologica Proc Series 48. Dordrecht: Martinus Nijhoff/Dr. W. Junk
Publishers,1987: 157-62.

Soriano HM. Echographic findings in accommodation. In: Ossoinig KC, ed.
Ophthalmic Echography, Proceedings of the 10th SIDUO Congress. Doc
Ophthalmologica Proc Series 48. Dordrecht: Martinus Nijhoff/Dr. W. Junk
Publishers, 1987: 163-9.

Shum PJT, Ko LS, Ng CL, Lin SL. A biometric study of ocular changes
during accommodation. Am J Ophthalmol 1993; 115: 76 - 81.