Otis?  Could you please answer the last question??

It wouldn't make you seem very credible if you have no sound basis for
these assertions, so I'm sure you'll be EAGER to clear this up.

Thanks.
--

And after all, getting a prescription that is somewhere in the ball park
is quite good enough, right?

In your little mind, perhaps they are.

How many patients have you refracted in this manner, and how did your
results compare to actual medically trained professionals who refracted
the same patients themselves?

Inquiring minds want to know.

Assuming you had a trial-lens "frame", and
a box of trial lenses (in 1/4 diopter steps),
and a days traing and experience you
could probably determine your refractive STATE
that would not be much difference that
a measurement made in an office.

After all they are the same thing.

What the OD can do in his office is to check
for retinal-organic problems.  And also
check for eye-ball pressure.

But once these items are cleared off the
table, then verifying your refractive STATE
would not take much training.

Just on man's opinion.

Otis

What I mean is, I can self prescribe my glasses so long as I pass the
vision test.  The FAA/DMV doesn't care as long as I can see.  The idea
that an Rx is required to protect the public from blind pilots doesn't
make sense.

--

Not my experience.  If you fail the vision screening, then you don't get
a driver's license without a form from an eye doctor.  I've done this
twice, my wife once.

None of these professions require proof of a doctor's prescription,
only proof that you can see.

--

The most obvious reason why lens prescriptions are legally required is to
minimize the risk of operating dangerous machinery, such as automobiles.
Can you imagine drivers, pilots, ship captains, etc. self-prescribing?
People cannot be trusted to be responsible and use common sense in such
situations.  How could you even tell if you hit on the correct prescription?

I can see why prescriptions are required for drugs, because those can
be easily abused or sold in the black market. But to me, eye
prescriptions don't seem that critical.

My analogy is shoes. You could probably mess up your
feet/knees/legs/back by wearing the wrong size or type of shoes, or
improper inserts long term. Yet a shoe prescription from a podiatrist
is not required for people to buy shoes.

Of course, everyone should get an initial refraction done
professionally. But what's wrong with buying disposable contacts that
are a little higher or lower than your prescription to see how they
perform? You're not going to be seriously injured. Maybe get some
headaches or eyestrain, that's all. And if you do have problems, then
go see the optometrist (just like you'd see a podiatrist if shoes were
giving you problems).