otisbrown@pa.net> wrote

In fact there are two DIFFERENT methods of judging
a person's refractive STATE.

Yes but your two "methods" don't really address her question, do they?

She is asking why you can't predict VA from refraction.

In article <QN2dnWfu16wm-AjYnZ2dnUVZ_o-knZ2d@giganews.com>,
"Mike Tyner" <mtyner@mindspring.com> wrote:

otisbrown@pa.net> wrote

In fact there are two DIFFERENT methods of judging
a person's refractive STATE.
Yes but your two "methods" don't really address her question, do they?

She is asking why you can't predict VA from refraction.


My wife was a chemist. Her boss was also. He wanted a formula to
convert volume into weight. She couldn't do that.

In article <QN2dnWfu16wm-AjYnZ2dnUVZ_o-knZ2d@giganews.com>,
"Mike Tyner" <mtyner@mindspring.com> wrote:

otisbrown@pa.net> wrote

In fact there are two DIFFERENT methods of judging
a person's refractive STATE.

Yes but your two "methods" don't really address her question, do they?

She is asking why you can't predict VA from refraction.

My wife was a chemist. Her boss was also. He wanted a formula to
convert volume into weight. She couldn't do that.

On 12/29/06 7:41 AM, in article
1167406898.484719.25500@i12g2000cwa.googlegroups.com, "otisbrown@pa.net"
otisbrown@pa.net> wrote:

For instance, one 2 year-old had a Snellen of
20/60 -- which is functional for a child of that age -- and
a retinoscope/cycloplegic of -11 diopters.

How can you even rely upon a 2 year-old to read a Snellen chart correctly?

Bill
-- Fermez le Bush

Good question.

There are Snellens that have pictures. By these means
an estimate of visual acuity can be obtained.

I would bet that if this two-year old were the
daughter of some of these ODs -- they
would do a lot more checking before
they put their child into a -10 diopter lens.

In fact I do believe that some children have
an adverse reaction to these drugs, that
"freeze" the accommodation at the
maximum "near" position of -10 diopters.

But let us say that some second-opinion
optometrists would suggest "holding off"
on plunging a child that age
into a -10 diopter lens.

Second-opinions vary on this subject.

Otis





Salmon Egg wrote:
On 12/29/06 7:41 AM, in article
1167406898.484719.25500@i12g2000cwa.googlegroups.com, "otisbrown@pa.net"
otisbrown@pa.net> wrote:

For instance, one 2 year-old had a Snellen of
20/60 -- which is functional for a child of that age -- and
a retinoscope/cycloplegic of -11 diopters.

How can you even rely upon a 2 year-old to read a Snellen chart correctly?

Bill
-- Fermez le Bush

I would bet that if this two-year old were the
daughter of some of these ODs -- they
would do a lot more checking before
they put their child into a -10 diopter lens.

In fact I do believe that some children have
an adverse reaction to these drugs, that
"freeze" the accommodation at the
maximum "near" position of -10 diopters.

But let us say that some second-opinion
optometrists would suggest "holding off"
on plunging a child that age
into a -10 diopter lens.