Why7
Subject: The Snellen Eye Charts
Note: We are in desperate need of a prevention-minded optometrist
like Steve Leung to help us with vision-clearing. See:
www.chinamyopia.org
There is a great deal that you can do to help yourself -- until
you find a supportive prevention-minded optometrist. Checking
your visual-acuity yourself is that first step.
+++++++++++++++++++++++++++++++++++++++++++++++++++
The Snellens are in on the myopiafree page:
It is a good idea to do a general verification check on
these Snellens.
The standard chart distance is 20 feet. Just measure
the 20/60 letter size. It must be one inch in size.
If that is correct, then the rest of the Snellen
should be accurate for your purposes.
In general, if you read 1/2 the letters correctly, you
pass that given line.
In most states the requirement is for 20/60 to
20/40 vision. These are the lines you MUST PASS
to receive a valid DMV license to drive a car
with naked-eye vision.
On the path to vision clearing you will "clear"
these lines. Obviously the goal is to get your
visual-acuity above these standards.
You should verify your vision before you
go take the DMV test.
It is often said that "vision improvment" is
because the person memorized the Snellen. This is
the reason you should use the IVAC (Random) Snellen,
for a very accurate confirmation of your
visual acuity.
That is why the IVAC-Monitor Snellen is best.
++++++++++++++++++++++++++
WHY PREVENTION IS NOT OFFERED.
(Except by Steve Leung OD)
We might ask why a myopia prevention discussion is not
offered by optometrists. Here are some of the reasons for this
reluctance to discuss the possibility of prevention with a person
whose vision is 20/50 to 20/70.
I acknowledge that it takes a strong person to implement
prevention at the 20/50 level -- when we judge that the effort
must start, so that the effort can become effective.
The one thing that bothered me as I was digging into the
question of nearsightedness was that I was challenging established
authority. This type of a questioning attitude is necessary in
science -- and we should understand some of the objections that
exist concerning effective prevention with a plus lens.
OPTOMETRISTS HAVE PRACTICALLY NO CHOICE
(IN MOST CASES) BUT TO USE THE MINUS LENS.
As I became friends with ophthalmologist and optometrists I
realized that they did not "love" the minus lens either -- but
they had no choice at all but to use it if vision was more
negative than 20/70.
Some optometrists have called the minus lens "poison glasses
for children". This fact should provide you with a sense of their
judgment (and frustration) about the secondary effect that the
minus lens on the eye.
In fact I greatly respect the few optometrists who challenge
the existing theory (Donders-Helmholtz). This concept insists
that the natural eye does not change its status in a negative
direction from either a forced confined environment or the forced
wearing of a minus lens.
Many optometrists have understood these basic facts. For this
reason they choose to NOT PRESCRIBE the minus lens at all. This
is possible, but ONLY if the child's distant vision meets the DMV
standard of 20/40 or better,
While the intention is understood, the decision to avoid the
use of a minus lens does not work in the long run. In other
words, doing nothing for "prevention" at that point does not work. This is
because the child will go back to his bad reading (at 4 inches)
habit -- and will simply gets deeper into it. See the analysis
of the effect of a primate eye in Chapter 6 of my book. Also
look at the -12 diopter picture if you do not believe me.
Eventually, with the habit of reading at 4 inches (optically,
-10 diopters) the eye becomes even more negative. When it is at
-0.75 diopters (20/60) the optometrist has no choice at all but to
apply the minus lens. A great deal of responsibility must
rest with "us" to prevent this bad habit in children. The
optometrist should be more forceful in explaining this type
of responsibility that we must assume.
There is need for a strong "second opinion" discussion
concerning the use of the plus lens at this point, and the
long-term consequences of NOT using the plus properly.
This is indeed a now-or-never decision. If the person can
master the "preventive" skills, then the child, parents and
optometrist can be effective in restoring the child's distant
vision to normal at that point.
But the effort must not stop at that point, and must be
continued AFTER the child reaches 20/20. In fact the strength of
the plus used for reading should be increased by +1/2 diopter,
when the child's vision changes by +1/2 diopter.
Since no optometrist or ophthalmologist can stop your child
from reading at 4 inches (optically -10 diopters) it follows that
the optometrist can only react to the eventual effect this bad
habit has on the child's focal status.
When you talk honestly with some ophthalmologists you find
that they also realize that this reading at 4 inches produces the
resultant (negative change of focus) of their eyes into
nearsightedness.
This is a major problem and the child and parents must
understand the need to stop this type of reading. Please click on
"-12 D" to see a child doing this. The "classical" theory insists
that reading at this distance has NO EFFECT ON THE REFRACTIVE
STATUS OF THE EYE. The development of nearsightedness can not be
stopped until this nose-on-the-book habit is stopped completely.
But the parents and their child often fail to recognize this
issue and problem at the time. For this reason the optometrists
states, " ...but the public will not accept advocacy for
prevention with a plus lens". In most cases they are right on
that point. They state that they have no choice but to do what
the public expects -- which is to make your child's vision
instantly sharp with a strong minus lens. Unless you are "wise"
about this issue at the threshold, you will not tolerate the use
of a plus lens for your child.
Until we learn to break ourselves of this cycle at the start
we can not resolve this issue of personal responsibility and
control for preventing nearsightedness. This is necessary a
"shared" responsibility with you and your child taking
responsibility to do what is necessary.
Tragically, both the doctor and patient seem to always be
marching downward by our use of the minus lens -- because it is so
easy and quick, and requires no discussion, review or choice. It
will take strong personal resolve to prevent this situation from
the start.
But let anyone suggest that "all natural eye move minus when
a minus lens is placed on them", (which is a matter of direct
experimental, scientific and factual truth) and a great many
people (including optometrists) get upset.
At some point you must begin to share "authority" -- by
putting on your "scientific hat" and acting more competently about
advocacy for prevention with a plus lens. To ignore the warning
about this issue is to accept the ultimate long-term consequences.
This intellectual and scientific process fact review should
lead to a restating of the problem. This work will produce a
better-organized effort at prevention.
In this struggle no one should suggest that I disrespect
optometrists. In fact they have argued FOR PREVENTION as the
"second opinion." I strongly support that advocacy, and we need
to understand the use of the plus on that basis.
PROFESSIONAL ADVOCACY FOR PREVENTION
In fact, the recommendations made on this site have been
amplified and repeated by the professionals. Dr. Theodore
Grosvenor of the University of Houston College of Optometry
insists that persistent close work causes the eye to "change" in a
negative direction.
He further states that, "Once the eye has started to stretch,
it may be too late to keep it from stretching". This should be a
warning to us about the need to start using the plus -- before the
minus lens is applied.
Further, as the minority opinion, we agree that, "The
ultimate study would be to put reading glasses on first-graders
before anyone has developed myopia" as Theodore states. What
prevents us from taking this major step for the welfare of our own
children?