Dear Don,

Subject: Consistent over-prescription by minus two diopters.

Re: People currently working with the plus for prevention

Re: Statements by ODs on sci.med.vision

Re: These various "mono-studies", and there implication.

For a long time I suspected that the minus was
"over-prescribed" -- but I did not know how much -- or why.

From reports of Mike who contacted me, I found that:

1. When he decided to go "cold turkey", he discovered that

a. His prescription was for -2.75 diopters. (a 1 diopter =
20/70, the would mean a visual-acuity of 20/200 --
approximately, or close to legal blindness). But Mike could
function with out the minus lens.

b. When I asked him to read a standard eye-chart, he reported a
"blurry" 20/70. The Florida DMV standard is 20/70 --
believe it or not.

2. Since he was alread working with out the minus lens, I stated
that he had to "clear" to 20/40 (1.8 cm at 6 meters) to
truly reject the legal requirement for a minus lens. Why
was Mike so serious over-prescribed?

a. The public "loves" over-prescription, so the ODs prescribe for
20/20. However, adolescent and children's eyes can "do
better" that 20/20. According to Stacy OD, his will keep on
"cranking" until he gets to 20/10. This probably adds 1
diopter to a prescription.

b. Thus a child that has 20/30 vision and has no rational need
for that minus -- gets a -1.5 to -2 diopter lens, and worse,
is told to "wear it all the time.

3. It was a lot of work (following Colgate's method) but Mike
gradually cleared to 20/40 and slightly better, i.e., passes
the legal standard for driving a care. At his mother's
requiest he went back to the OD.

a. The OD puts him in a darkened room, with a low-illumination
Snellen, and "cranks" on that minus lens, and insists that
Mike's prescription is -2.0 diopters. Why this conflict?

b. As far as I am concerned, a person who PASSES all legal
visual-acuity standards that apply to him, is
over-prescribed by the prescription -- which is not
necessary, i.e., -2 diopters.

4. I believe that a -2 diopter lens will totally PREVENT
vision-restoration -- if it is worn all the time -- and
particularly when there is no legal need for it.

5. I appreciate the idea that the OD believes that he is doing
wonderful work when he "prescribes" this -2 diopter lens,
but I think he has fallen in "love" with practice, and
really has no idea of the long-term damage he is doing. It
is tragic that NO ONE raises this issue.


Fortunately, Mike has understood these issues. Currently he
reports 20/30 to 20/25, which is incredible considering his
prescription of -2.75 dioters. I have no idea if Mike can reach
20/20, but I do know that that "last" step seems to be the most
difficult. There is nothing "easy" in any of this.

Best,


Otis

______________________________


To: "Otis Brown" <otisbrown@...>

Subject: phillips paper

Date: Thursday, September 01, 2005 3:16 PM

Otis.

Someone sent me this:

Don Rehm


Br J Ophthalmol. 2005 Sep;89(9):1196-200.

Monovision slows juvenile myopia progression unilaterally.

Phillips JR.

Department of Optometry and Vision Science, University of
Auckland, Private Bag 92019, Auckland, New Zealand.
j.phillips@....

AIM: To evaluate the acceptability, effectivity, and side effects
of a monovision spectacle correction designed to reduce
accommodation and myopia progression in schoolchildren.

METHODS: Dominant eyes of 11 year old children with myopia (-1.00
to -3.00 D mean spherical equivalent) were corrected for
distance; fellow eyes were uncorrected or corrected to
keep the refractive imbalance < / = 2.00 D. Myopia
progression was followed with cycloplegic autorefraction
and A-scan ultrasonography measures of vitreous chamber
depth (VCD) for up to 30 months. Dynamic retinoscopy
was used to assess accommodation while reading.

RESULTS: All children accommodated to read with the distance
corrected (dominant) eye. Thus, the near corrected eye
experienced myopic defocus at all levels of
accommodation. Myopia progression in the near corrected
eyes was significantly slower than in the distance
corrected eyes (inter-eye difference = 0.36 D/year (95%
CI: 0.54 to 0.19, p = 0.0015, n = 13); difference in
VCD elongation = 0.13 mm/year (95% CI: 0.18 to 0.08, p
= 0.0003, n = 13)). After refitting with conventional
spectacles, the resultant anisometropia returned to
baseline levels after 9-18 months.

CONCLUSIONS: Monovision is not effective in reducing
accommodation in juvenile myopia. However, myopia
progression was significantly reduced in the near
corrected eye, suggesting that sustained myopic defocus
slows axial elongation of the human eye.