So this two-year-old was checked only once?

And she's wearing them because an OD recommended it?

Some children accommodate excessively after cyclopentolate? That would make
a nice article, if you could find one.

And some would say we did.

And some would say it isn't your business.

-MT

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

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

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

Bill
-- Fermez le Bush

Dear Katy,

I would also add, that sometimes the difference between
Snellen and Retinoscope/cycloplegic can be profound.

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.

So what do you do?  Tell the mother that 20/60 is
OK for now, or "prescribe" based on the retinoscope/cycloplegic.

For the case in question, the child is now wearing a -10 dioper
lens all the time.

Obviously there is a majority and second opinion on this
subject.

Just one man's opinion.

Best,

Otis

Dear Katy,

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

1.  Use a Snellen and a trial lens kit.  (The so-called
"subjective" measurement).  In this method you
have the person read the snellen at say 20/50.  You
then use stronger minus lenses until the 20/20
line is cleared, with say a -3/4 diopter lens.)

2.  Measure with a retinoscope/cycloplegic (drops),
and determine a person's refractive STATE.

These two methods often do not agree -- and
can be profoundly different.

In fact it is possible to have 20/20 and a reafractive
STATE (cycloplegic) of -3/4 diopters.

This my explain some of the difference between
your refractive measurement and your current
visual acuity.

It is also true as suggested by the ODs on
sci.med.vision, that as you get older your
refractive STATE will change in a positive
direction, and your Snellen will clear.

That might also explain why you can
get along with no minus lens.

Obviously, opinions vary concerning your
distant visual acuity.

Best,

Otis

Is there a scientific explanation for why two people with the same
prescription appear to have different levels of vision?  For example, I've
read somewhere that two people who are -3 won't necessarily see the same
without glasses, one might see better/worse than the other.  What factors
influence this?