How to perform retinoscopy

How to perform retinoscopy

How does one perform static retinoscopy using a direct retinoscope? Do
dilate the eyes w/ atropine, darken the lights, take the retinoscope,
stand 20' away, and try to neutralize the cat's-eye reflex w/ the
phoropter?

Which is better, direct or indirect, sreak or spot?

Thanks!

Re: How to perform retinoscopy


Dear Friend,

A Phoropter is used to measure the refractive status of the eye.

It is basically and "enhanced" trial-lens kit.

If you are nearsighed, say 20/70, then then a minus lens (in the
Phoropter) is
used to clear the Snellen. Typically, about -1.25 diopters is used to
clear the 20/20 line. If you are being prescribed for "Best Visual
Acuity",
then you will get a much stronger minus lens for your prescription.

That is one means to determine your refractive STATE.

A retinascope and induced paralysis creates a profoundly
different measurement. (By some people this is a so-called
"objective" measurement.)

Enjoy,





On Apr 29, 6:52 pm, douglas <Protoman2...@gmail . com > wrote:
> How does one perform static retinoscopy using a direct retinoscope? Do
> dilate the eyes w/ atropine, darken the lights, take the retinoscope,
> stand 20' away, and try to neutralize the cat's-eye reflex w/ the
> phoropter?
>
> Which is better, direct or indirect, sreak or spot?
>
> Thanks!

Re: How to perform retinoscopy

You'll, of course, have to forgive Otis.

He's ... well ... he's stupid.

Re: How to perform retinoscopy

On Apr 29, 8:01 pm, Neil Brooks <neil0...@yahoo . com > wrote:
> You'll, of course, have to forgive Otis.
>
> He's ... well ... he's stupid.

And, the correct answer I'm looking for is...?

Re: How to perform retinoscopy


Do you wish to make the measurement?



On Apr 29, 11:22 pm, douglas <Protoman2...@gmail . com > wrote:
> On Apr 29, 8:01 pm, Neil Brooks <neil0...@yahoo . com > wrote:
>
> > You'll, of course, have to forgive Otis.
>
> > He's ... well ... he's stupid.
>
> And, the correct answer I'm looking for is...?

Re: How to perform retinoscopy

On Apr 29, 9:29 pm, otisbr...@embarqmail . com wrote:
> Dear Friend,
>
> A Phoropter is used to measure the refractive status of the eye.
>
> It is basically and "enhanced" trial-lens kit.
>
> If you are nearsighed, say 20/70, then then a minus lens (in the
> Phoropter) is
> used to clear the Snellen. Typically, about -1.25 diopters is used to
> clear the 20/20 line. If you are being prescribed for "Best Visual
> Acuity",
> then you will get a much stronger minus lens for your prescription.
>
> That is one means to determine your refractive STATE.
>
> A retinascope and induced paralysis creates a profoundly
> different measurement. (By some people this is a so-called
> "objective" measurement.)
>
> Enjoy,
>
> On Apr 29, 6:52 pm, douglas <Protoman2...@gmail . com > wrote:
>
> > How does one perform static retinoscopy using a direct retinoscope? Do
> > dilate the eyes w/ atropine, darken the lights, take the retinoscope,
> > stand 20' away, and try to neutralize the cat's-eye reflex w/ the
> > phoropter?
>
> > Which is better, direct or indirect, sreak or spot?
>
> > Thanks!

Here goes Otis with his misinformation again!

If you are a 20/70 myope, then minus lenses will restore your distance
acuity, Its hard to predict, but assuming no astigmatism, I would
guess
about -1.5D should be close to providing clear 20/20 distance vision.
Of course there might some astigmatism also playing into the senario
but Otis likes to make things simple so we are pretending the patient
is a simple myope.

Most accomplished refractionists prefer a streak retinoscope for the
exam. A retinoscope is held about 16" from the eyes while the patient
is looking at a distance target using a working distance of optical
infinity or about 20 ft. The minimum lens strength that is necessary
to give the patient clear 20/20 vision is determined as the spectacle
prescription. As Otis likes to imply, patients are not overcorrected
(i.e. given excess minus lens power) to obtain clear BVA. Giving
excessive power minus lenses is harmful in that it can gives patient
eyestrain, and makes it less comfortable than using the exact
emmetropic state.

Re: How to perform retinoscopy

In article
<0f4a0581-24fc-42dd-9a5e-864907bcfbb6@m44g2000hsc.googlegroups . com >,
retinula <retinula@hotmail . com > wrote:

> On Apr 29, 9:29 pm, otisbr...@embarqmail . com wrote:
> > Dear Friend,

> > That is one means to determine your refractive STATE.

I don't need it. I already know. It is California.

> Here goes Otis with his misinformation again!

I seldom let Otis give me misinformation anymore. I just don't normally
read what he posts.

--
Dan Abel
Petaluma, California USA
dabel@sonic . net

Re: How to perform retinoscopy


"douglas" <Protoman2050@gmail . com > wrote

> How does one perform static retinoscopy using a direct retinoscope?

"Direct" and "indirect" don't apply to retinoscopes. Ophthalmoscopes yes.

> Do
> dilate the eyes w/ atropine, darken the lights, take the retinoscope,
> stand 20' away, and try to neutralize the cat's-eye reflex w/ the
> phoropter?

You could stand at 20 feet but it'd be unworkable. Better to stand at 67 cm
and use a +1.50 lens over the patient's eye as your "zero," simulating
infinity (1/1.50=0.67).

Three advantages - you can reach the patient, you can see the reflex better,
and using +1.50 over both eyes "fogs" the vision in a way that encourages
the patient to relax accommodation.

If your arms are short, you could test at 50 cm and use a +2.00 "fogging"
lens to simulate optical infinity.

You could dilate, and that's helpful sometimes, but I'm usually more
interested in the patient's "habitual" refractive state. Artificially
eliminating accommodation with atropine gives an "objective" result but you
don't walk around every day with atropine in your eyes. You don't buy size
34 pants just because you can suck in your 38 belly and squeeze into them in
the dressing room.

I work at 67 cm. If it takes +2.50 to neutralize the reflex, I know this is
a +1.00 hyperope. If the reflex neutralizes at -1.00, it's a -2.50 myope.

> Which is better, direct or indirect, sreak or spot?

There is no direct/indirect afaik.

Most retinoscopes these days are streak. IMO it's easier to determine axis
with a streak. because the streak reflex "twists" better, indicating axis.
But vertical/horizontal differences appear readily in the moving light,
whether it's spot or streak, and some old optometrists will be buried with
their spot scopes; for me it's a Copeland streak.

Early ret was done with a gas flame behind the patient's head. The "scope"
was a flat handheld mirror with an observation hole in the center. Modern
scopes aren't fundamentally different.

-MT

Re: How to perform retinoscopy

On Apr 29, 6:52 pm, douglas <Protoman2...@gmail . com > wrote:
> How does one perform static retinoscopy using a direct retinoscope? Do
> dilate the eyes w/ atropine, darken the lights, take the retinoscope,
> stand 20' away, and try to neutralize the cat's-eye reflex w/ the
> phoropter?

It would be impossible to do at 20', the reflex would be far too dim
and you would be unable to reach either the phoropter or trial lenses
in a trial case.

Can be done with or without cycloplegia. Usually done at 50cm or
67cm, depending on the length of the examiner's arms. Either loose
lenses in trial frame, lens bar or lenses in phoropter can be used.
An allowance is made for the working distance.

>
> Which is better, direct or indirect, sreak or spot?

There is no indirect retinoscope, streak is preferred as it is much
easier to detect astigmatism with it.

Judy

Re: How to perform retinoscopy

On Apr 30, 6:10 am, Dr Judy <mpac...@rogers . com > wrote:
> On Apr 29, 6:52 pm, douglas <Protoman2...@gmail . com > wrote:
>
> > How does one perform static retinoscopy using a direct retinoscope? Do
> > dilate the eyes w/ atropine, darken the lights, take the retinoscope,
> > stand 20' away, and try to neutralize the cat's-eye reflex w/ the
> > phoropter?
>
> It would be impossible to do at 20',  the reflex would be far too dim
> and you would be unable to reach either the phoropter or trial lenses
> in a trial case.
>
> Can be done with or without cycloplegia.  Usually done at 50cm or
> 67cm, depending on the length of the examiner's arms.  Either loose
> lenses in trial frame, lens bar or lenses in phoropter can be used.
> An allowance is made for the working distance.
>
>
>
> > Which is better, direct or indirect, sreak or spot?
>
> There is no indirect retinoscope, streak is preferred as it is much
> easier to detect astigmatism with it.
>
> Judy

OK, I know how to check the base refractive error, but how do you
check for astigmatism? I know the retinoscope has a protractor on it,
and I'm pretty sure you use it just for that, but...how?

If you did both a static cycloplegic and a dynamic non-cycloplegic
retinoscopy on your patient, which reading would you use, or would you
somehow combine the readings? Coul you give me an example?

Who makes good retinoscopes? Keeler? And what's the diff b/w a
retinoscope and an ophthalmoscope? Can you use a indirect
ophthalmoscope for retinoscopy?

And has any beginning optometry student accidently held the
retinoscope backwards, and temporarily blinded themselves?

Thanks!

Re: How to perform retinoscopy

Dear Doug,

You can not self-measure your refractive STATE with
a retinoscope.

You will have to enlist the support of another person who
has your interest in measuring the eye's refractive STATE.

With support, you (and your friend) could probably learn
to make these measurements in a day. With practice,
accuractly, in a week. But you need an educated
friend to help you -- and help each other.

Doug> Who makes good retinoscopes? Keeler? And what's the diff b/w a
retinoscope and an ophthalmoscope? Can you use a indirect
ophthalmoscope for retinoscopy?


Doug> And has any beginning optometry student accidently held the
retinoscope backwards, and temporarily blinded themselves?

Otis> Each and ever day.

Enjoy,








On Apr 30, 11:02 pm, douglas <Protoman2...@gmail . com > wrote:
> On Apr 30, 6:10 am, Dr Judy <mpac...@rogers . com > wrote:
>
>
>
>
>
> > On Apr 29, 6:52 pm, douglas <Protoman2...@gmail . com > wrote:
>
> > > How does one perform static retinoscopy using a direct retinoscope? Do=

> > > dilate the eyes w/ atropine, darken the lights, take the retinoscope,
> > > stand 20' away, and try to neutralize the cat's-eye reflex w/ the
> > > phoropter?
>
> > It would be impossible to do at 20',  the reflex would be far too dim
> > and you would be unable to reach either the phoropter or trial lenses
> > in a trial case.
>
> > Can be done with or without cycloplegia.  Usually done at 50cm or
> > 67cm, depending on the length of the examiner's arms.  Either loose
> > lenses in trial frame, lens bar or lenses in phoropter can be used.
> > An allowance is made for the working distance.
>
> > > Which is better, direct or indirect, sreak or spot?
>
> > There is no indirect retinoscope, streak is preferred as it is much
> > easier to detect astigmatism with it.
>
> > Judy
>
> OK, I know how to check the base refractive error, but how do you
> check for astigmatism? I know the retinoscope has a protractor on it,
> and I'm pretty sure you use it just for that, but...how?
>
> If you did both a static cycloplegic and a dynamic non-cycloplegic
> retinoscopy on your patient, which reading would you use, or would you
> somehow combine the readings? Coul you give me an example?
>
> Who makes good retinoscopes? Keeler? And what's the diff b/w a
> retinoscope and an ophthalmoscope? Can you use a indirect
> ophthalmoscope for retinoscopy?
>
> And has any beginning optometry student accidently held the
> retinoscope backwards, and temporarily blinded themselves?
>
> Thanks!- Hide quoted text -
>
> - Show quoted text -

Re: How to perform retinoscopy


"douglas" <Protoman2050@gmail . com > wrote

> OK, I know how to check the base refractive error, but how do you
> check for astigmatism? I know the retinoscope has a protractor on it,

You don't see protractor markings on modern retinoscopes. The markings are
on the phoropter.

> I'm pretty sure you use it just for that, but...how?

Once you get a good reflex, you rotate the streak and sweep it in different
directions across the pupil. Many times it's obvious that the streak
neutralizes in one meridian (say, sweeping side-to-side) yet it's way off
90 degrees away, when you sweep up-and-down. That's astigmatism, and the
trick is to determine the maximum and minimum meridians.

> If you did both a static cycloplegic and a dynamic non-cycloplegic

Dynamic retinoscopy isn't useful for determining refractive error. Many
doctors never use dynamic and have forgotten how, because it's only valuable
for determining accommodative response and there are other ways to do that.
A few years ago the "Prio system" was pushed out, basically an LCD nearpoint
card with a hole it it, thru which you could do dynamic retinoscopy. It was
gimmicky ("computer vision") and seldom indicated any unique sort of
treatment, but you were obligated to prescripe Prio lenses from it. It
wasn't that much better than a plastic nearpoint card with the same hole.

Retinoscopy is a dying art. Most retinoscopy used to be done to gain a
starting point for subjective refraction, an estimate. Many doctors now use
autorefractors for that, and consequently never pick up a retinoscope. I
wouldn't either, except sometimes I get ahead of my staff and patients
haven't had the autorefraction done yet.

Cycloplegic retinoscopy may be used to help determine latent hyperopia but
dry (non-cyclo) ret is often a good indicator of LH, revealing results that
are a half- or full diopter more plus than the patient's chosen subjective.

> Who makes good retinoscopes? Keeler?

Copeland and Welch-Allyn. Don't know the Keeler.

> And what's the diff b/w a
> retinoscope and an ophthalmoscope?

BIG diff. A ret just generates a streak of light. The streak can be focused
but it's designed to focus an image of the filament (the streak) to the
retina, such that you can see it moving in the pupil.

Ophthalmoscopes are illuminated too, but more important they have an
observation system that lets you see the details of what you're
illuminating. Direct and indirect o'scopes both produce an image of the
retina. In direct scopes, the image is upright and magnified. Indirect
scopes produce upside-down images that are wider-field (less detailed, not
as magnified.)

> Can you use a indirect
> ophthalmoscope for retinoscopy?

Not very well, I'm not sure it could be done because retinoscopes all focus
the streak in different planes. The ophthalmoscope generates only parallel
light for illumination.

>And has any beginning optometry student accidently held the
> retinoscope backwards, and temporarily blinded themselves?

Oh sure. Ophthalmoscopes are much brighter. But with all hand-held scopes,
it's habit to turn it on, then shine it somewhere like your hand or the
wall, to make sure it's working. Putting it to your eye backwards is dumb
but even dumber is getting up in your patient's face then finding the scope
is dead.

-MT

Re: How to perform retinoscopy

On May 1, 9:21 am, "Mike Tyner" <mty...@mindspring . com > wrote:
> "douglas" <Protoman2...@gmail . com > wrote
>
> > OK, I know how to check the base refractive error, but how do you
> > check for astigmatism? I know the retinoscope has a protractor on it,
>
> You don't see protractor markings on modern retinoscopes. The markings are=

> on the phoropter.
>
> > I'm pretty sure you use it just for that, but...how?
>
> Once you get a good reflex, you rotate the streak and sweep it in differen=
t
> directions across the pupil. Many times it's obvious that the streak
> neutralizes in one meridian (say, sweeping side-to-side) yet it's way off
> 90 degrees away, when you sweep up-and-down. That's astigmatism, and the
> trick is to determine the maximum and minimum meridians.
>
> > If you did both a static cycloplegic and a dynamic non-cycloplegic
>
> Dynamic retinoscopy isn't useful for determining refractive error. Many
> doctors never use dynamic and have forgotten how, because it's only valuab=
le
> for determining accommodative response and there are other ways to do that=
.
> A few years ago the "Prio system" was pushed out, basically an LCD nearpoi=
nt
> card with a hole it it, thru which you could do dynamic retinoscopy. It wa=
s
> gimmicky ("computer vision") and seldom indicated any unique sort of
> treatment, but you were obligated to prescripe Prio lenses from it. It
> wasn't that much better than a plastic nearpoint card with the same hole.
>
> Retinoscopy is a dying art. Most retinoscopy used to be done to gain a
> starting point for subjective refraction, an estimate. Many doctors now us=
e
> autorefractors for that, and consequently never pick up a retinoscope. I
> wouldn't either, except sometimes I get ahead of my staff and patients
> haven't had the autorefraction done yet.
>
> Cycloplegic retinoscopy may be used to help determine latent hyperopia but=

> dry (non-cyclo) ret is often a good indicator of LH, revealing results tha=
t
> are a half- or full diopter more plus than the patient's chosen subjective=
.
>
> > Who makes good retinoscopes? Keeler?
>
> Copeland and Welch-Allyn. Don't know the Keeler.
>
> > And what's the diff b/w a
> > retinoscope and an ophthalmoscope?
>
> BIG diff. A ret just generates a streak of light. The streak can be focuse=
d
> but it's designed to focus an image of the filament (the streak) to the
> retina, such that you can see it moving in the pupil.
>
> Ophthalmoscopes are illuminated too, but more important they have an
> observation system that lets you see the details of what you're
> illuminating. Direct and indirect o'scopes both produce an image of the
> retina. In direct scopes, the image is upright and magnified. Indirect
> scopes produce upside-down images that are wider-field (less detailed, not=

> as magnified.)
>
> > Can you use a indirect
> > ophthalmoscope for retinoscopy?
>
> Not very well, I'm not sure it could be done because retinoscopes all focu=
s
> the streak in different planes. The ophthalmoscope generates only parallel=

> light for illumination.
>
> >And has any beginning optometry student accidently held the
> > retinoscope backwards, and temporarily blinded themselves?
>
> Oh sure. Ophthalmoscopes are much brighter.  But with all hand-held scop=
es,
> it's habit to turn it on, then shine it somewhere like your hand or the
> wall, to make sure it's working. Putting it to your eye backwards is dumb
> but even dumber is getting up in your patient's face then finding the scop=
e
> is dead.
>
> -MT

But I'm sure you could use a direct ophthalmoscope for retinoscopy, if
you lacked a retnoscope, would the procedure be any different for
using an ophthalmoscope for static retinoscopy? Which provides better
bva, cyclo, or non-cyclo?

Re: How to perform retinoscopy


Dear Doug,

Subject: Best Visual Acuity -- METHOD

This is the standard that is preferred by most ODs.

Using a trial lens kit (or Phoropter), and a minus lens -- you do the
following.

Have the person read the Snellen. OK, 20/70

Now you place a weak minus lens in your trial-lens frame, of -1
diopter.


20/30, OK

You then increase the power (asking 1 or 2 better) until you get the
sharpest
vision possible.

20/20. OK with a -1.5 diopter lens.

Now let is see if we can do better. Using a cyl lens, you rotate the
lens
from zero to 90 degrees, looking for that to sharpen the image.

So you get to 20/15 for that person.

You think write the prescription for the Spherical and Cyl and angle.

Enjoy,






On May 1, 3:18 pm, douglas <Protoman2...@gmail . com > wrote:
> On May 1, 9:21 am, "Mike Tyner" <mty...@mindspring . com > wrote:
>
>
>
>
>
> > "douglas" <Protoman2...@gmail . com > wrote
>
> > > OK, I know how to check the base refractive error, but how do you
> > > check for astigmatism? I know the retinoscope has a protractor on it,
>
> > You don't see protractor markings on modern retinoscopes. The markings a=
re
> > on the phoropter.
>
> > > I'm pretty sure you use it just for that, but...how?
>
> > Once you get a good reflex, you rotate the streak and sweep it in differ=
ent
> > directions across the pupil. Many times it's obvious that the streak
> > neutralizes in one meridian (say, sweeping side-to-side) yet it's way of=
f
> > 90 degrees away, when you sweep up-and-down. That's astigmatism, and the=

> > trick is to determine the maximum and minimum meridians.
>
> > > If you did both a static cycloplegic and a dynamic non-cycloplegic
>
> > Dynamic retinoscopy isn't useful for determining refractive error. Many
> > doctors never use dynamic and have forgotten how, because it's only valu=
able
> > for determining accommodative response and there are other ways to do th=
at.
> > A few years ago the "Prio system" was pushed out, basically an LCD nearp=
oint
> > card with a hole it it, thru which you could do dynamic retinoscopy. It =
was
> > gimmicky ("computer vision") and seldom indicated any unique sort of
> > treatment, but you were obligated to prescripe Prio lenses from it. It
> > wasn't that much better than a plastic nearpoint card with the same hole=
.
>
> > Retinoscopy is a dying art. Most retinoscopy used to be done to gain a
> > starting point for subjective refraction, an estimate. Many doctors now =
use
> > autorefractors for that, and consequently never pick up a retinoscope. I=

> > wouldn't either, except sometimes I get ahead of my staff and patients
> > haven't had the autorefraction done yet.
>
> > Cycloplegic retinoscopy may be used to help determine latent hyperopia b=
ut
> > dry (non-cyclo) ret is often a good indicator of LH, revealing results t=
hat
> > are a half- or full diopter more plus than the patient's chosen subjecti=
ve.
>
> > > Who makes good retinoscopes? Keeler?
>
> > Copeland and Welch-Allyn. Don't know the Keeler.
>
> > > And what's the diff b/w a
> > > retinoscope and an ophthalmoscope?
>
> > BIG diff. A ret just generates a streak of light. The streak can be focu=
sed
> > but it's designed to focus an image of the filament (the streak) to the
> > retina, such that you can see it moving in the pupil.
>
> > Ophthalmoscopes are illuminated too, but more important they have an
> > observation system that lets you see the details of what you're
> > illuminating. Direct and indirect o'scopes both produce an image of the
> > retina. In direct scopes, the image is upright and magnified. Indirect
> > scopes produce upside-down images that are wider-field (less detailed, n=
ot
> > as magnified.)
>
> > > Can you use a indirect
> > > ophthalmoscope for retinoscopy?
>
> > Not very well, I'm not sure it could be done because retinoscopes all fo=
cus
> > the streak in different planes. The ophthalmoscope generates only parall=
el
> > light for illumination.
>
> > >And has any beginning optometry student accidently held the
> > > retinoscope backwards, and temporarily blinded themselves?
>
> > Oh sure. Ophthalmoscopes are much brighter.  But with all hand-held sc=
opes,
> > it's habit to turn it on, then shine it somewhere like your hand or the
> > wall, to make sure it's working. Putting it to your eye backwards is dum=
b
> > but even dumber is getting up in your patient's face then finding the sc=
ope
> > is dead.
>
> > -MT
>
> But I'm sure you could use a direct ophthalmoscope for retinoscopy, if
> you lacked a retnoscope, would the procedure be any different for
> using an ophthalmoscope for static retinoscopy? Which provides better
> bva, cyclo, or non-cyclo?- Hide quoted text -
>
> - Show quoted text -

Re: How to perform retinoscopy

On May 1, 3:31 pm, otisbr...@embarqmail . com wrote:
> Dear Doug,
>
> Subject:  Best Visual Acuity -- METHOD
>
> This is the standard that is preferred by most ODs.
>
> Using a trial lens kit (or Phoropter), and a minus lens -- you do the
> following.
>
> Have the person read the Snellen.  OK, 20/70
>
> Now you place a weak minus lens in your trial-lens frame, of -1
> diopter.
>
> 20/30, OK
>
> You then increase the power (asking 1 or 2 better) until you get the
> sharpest
> vision possible.
>
> 20/20.  OK with a -1.5 diopter lens.
>
> Now let is see if we can do better.  Using a cyl lens, you rotate the
> lens
> from zero to 90 degrees, looking for that to sharpen the image.
>
> So you get to 20/15 for that person.
>
> You think write the prescription for the Spherical and Cyl and angle.
>
> Enjoy,
>
> On May 1, 3:18 pm, douglas <Protoman2...@gmail . com > wrote:
>
>
>
> > On May 1, 9:21 am, "Mike Tyner" <mty...@mindspring . com > wrote:
>
> > > "douglas" <Protoman2...@gmail . com > wrote
>
> > > > OK, I know how to check the base refractive error, but how do you
> > > > check for astigmatism? I know the retinoscope has a protractor on it=
,
>
> > > You don't see protractor markings on modern retinoscopes. The markings=
are
> > > on the phoropter.
>
> > > > I'm pretty sure you use it just for that, but...how?
>
> > > Once you get a good reflex, you rotate the streak and sweep it in diff=
erent
> > > directions across the pupil. Many times it's obvious that the streak
> > > neutralizes in one meridian (say, sweeping side-to-side) yet it's way =
off
> > > 90 degrees away, when you sweep up-and-down. That's astigmatism, and t=
he
> > > trick is to determine the maximum and minimum meridians.
>
> > > > If you did both a static cycloplegic and a dynamic non-cycloplegic
>
> > > Dynamic retinoscopy isn't useful for determining refractive error. Man=
y
> > > doctors never use dynamic and have forgotten how, because it's only va=
luable
> > > for determining accommodative response and there are other ways to do =
that.
> > > A few years ago the "Prio system" was pushed out, basically an LCD nea=
rpoint
> > > card with a hole it it, thru which you could do dynamic retinoscopy. I=
t was
> > > gimmicky ("computer vision") and seldom indicated any unique sort of
> > > treatment, but you were obligated to prescripe Prio lenses from it. It=

> > > wasn't that much better than a plastic nearpoint card with the same ho=
le.
>
> > > Retinoscopy is a dying art. Most retinoscopy used to be done to gain a=

> > > starting point for subjective refraction, an estimate. Many doctors no=
w use
> > > autorefractors for that, and consequently never pick up a retinoscope.=
I
> > > wouldn't either, except sometimes I get ahead of my staff and patients=

> > > haven't had the autorefraction done yet.
>
> > > Cycloplegic retinoscopy may be used to help determine latent hyperopia=
but
> > > dry (non-cyclo) ret is often a good indicator of LH, revealing results=
that
> > > are a half- or full diopter more plus than the patient's chosen subjec=
tive.
>
> > > > Who makes good retinoscopes? Keeler?
>
> > > Copeland and Welch-Allyn. Don't know the Keeler.
>
> > > > And what's the diff b/w a
> > > > retinoscope and an ophthalmoscope?
>
> > > BIG diff. A ret just generates a streak of light. The streak can be fo=
cused
> > > but it's designed to focus an image of the filament (the streak) to th=
e
> > > retina, such that you can see it moving in the pupil.
>
> > > Ophthalmoscopes are illuminated too, but more important they have an
> > > observation system that lets you see the details of what you're
> > > illuminating. Direct and indirect o'scopes both produce an image of th=
e
> > > retina. In direct scopes, the image is upright and magnified. Indirect=

> > > scopes produce upside-down images that are wider-field (less detailed,=
not
> > > as magnified.)
>
> > > > Can you use a indirect
> > > > ophthalmoscope for retinoscopy?
>
> > > Not very well, I'm not sure it could be done because retinoscopes all =
focus
> > > the streak in different planes. The ophthalmoscope generates only para=
llel
> > > light for illumination.
>
> > > >And has any beginning optometry student accidently held the
> > > > retinoscope backwards, and temporarily blinded themselves?
>
> > > Oh sure. Ophthalmoscopes are much brighter.  But with all hand-held =
scopes,
> > > it's habit to turn it on, then shine it somewhere like your hand or th=
e
> > > wall, to make sure it's working. Putting it to your eye backwards is d=
umb
> > > but even dumber is getting up in your patient's face then finding the =
scope
> > > is dead.
>
> > > -MT
>
> > But I'm sure you could use a direct ophthalmoscope for retinoscopy, if
> > you lacked a retnoscope, would the procedure be any different for
> > using an ophthalmoscope for static retinoscopy? Which provides better
> > bva, cyclo, or non-cyclo?- Hide quoted text -
>
> > - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

That's subjectively. And, according to House, patients lie. So, how do
we use retinoscopy to *objectively* determine our patient's refractive
error? I believe its as follows:

Dim the lights, instill cyclopentolate into the patient's eyes, and
have them look at at a target at optical infinity. You stand 67cm away
from the patient, and set the phoropter to -1.50D --please explain to
me exactly why this is done? To set the effective curvature to zero,
perhaps? And I know that -1.50D is the reciprical of 67cm--, and move
the retinoscope across the pupil. If you see with-motion, add plus
lenses; against-motion, add minus lenses. Stop when the pupil fills w/
light, and there's no motion. Rinse and repeat for all meridians.
Rinse and repeat for the other eye. Subtract -1.50D from the readings
to get the prescription.

How would you use the autorefractor to find an inital starting point
for the static retinoscopy?