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Retinoscopy Workshop (Video)

This video lecture describes the process of loose-lens retinoscopy from start to finish. You’ll learn the theory of how retinoscopy works to estimate glasses prescription, then run through 20 different patients with increasing complexity of astigmatism error. This is probably the best presentation on the internet to learn this difficult-to-learn skill:

length: 24:37 minutes

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Retinoscopy.m4v (195 MB)


(comments below)

Three Steps to Retinoscopy

1. Start with WITH motion
You need to the retina reflection to be “with” in all directions. If you see “against” motion in the beginning, you might need to hold up a -2.00, -4.00, or even a -10.00 lens in front of the eyes to get that “with” motion. Only then can you proceed without getting confused!!!

2. ADD power to neutralize reflex
Slowly add more power (plus power) until you neutralize the red-reflex. If you see “against” motion, you’ve gone too far. If the patient has astigmatism, you may get different powers for each axis … don’t worry. Just set the lenses aside so you can calculate the prescription later. Remember: the sphere power is your first lens, the cylinder power is the difference between the lenses. The axis is the angle your light beam ends up at (see example below)

3. SUBTRACT working distance at end
The last step is to subtract -1.50 from the sphere.

When the image is focused behind the retina, you see "with motion" as the reflection bounces off the retina.

When you use the perfect lens power, the reflection will be bright.

You add power until you neutralize the reflex. If you use too much power, like here, you see a "see-saw" movement of the light reflex. This is called "against" motion.

You subtract a working distance to compensate for your arm-length. For most people this is -1.50

The Final Prescription: -2.50 + 5.00 at 045


Best explanation I have ever had on this topic, (I don’t know how many attempts I made to learn the retinoscopy in observing my prof)

Margherita Montali
p.s. only a question: can you determine accurately the axis with the retinoscopy?
I mean how can you be sure than what are you measuring, for example, in an axis of 60° instead of 70°? Because, I notice, in the prescription of glasses, normally the patient can appreciate a difference of 10°.

Comment by Dr. M. Montali — November 7, 2010

Thanks Dr. Montali,
In answer to your question … no, I can’t always tell the exact axis using retinoscopy, though we can often get close.

If I have an adult (who might notice these subtle axis issues) than I can usually get them up to the phoropter anyway. I start with my retinoscopy estimation, then using the phoropter I tweak my power and axis to the exact prescription.

In kids, I just do the best I can and trust my retinoscopy. I like to put my final prescription in a trial frame to make sure the kid likes it (if old enough). Good luck!

-Tim Root

Comment by admin — November 7, 2010

Thanks Dr. Root,
yes I see.
Can I take up your time once again?

When I was student (in Italy), my prof told me it was the best technique to measure the refractives troubles. Now I am in Switzerland, and I continue to be surprise they prefer do another kind of measuration: once obtained the cycloplegia they use the autorefratometer.
What do you think about?
Margherita M.

Comment by Dr. M. Montali — November 8, 2010

The autorefractor is fine … we use it in our clinic prior to refracting new patients and children (if old enough). It gives a good place to start before manifest refraction with the phoropter. Plus, technicians can use the autorefractor with minimal training.

However, you can’t autorefract everyone … including young children, wheel-chair patients, or the demented. Also, the autorefractor is sometimes wrong or the machine refuses to take a good reading. In these cases, loose-lens refraction is the only way to go.

Comment by Tim Root — November 8, 2010

Brilliant approach, thanks so much. You are really making a difference in the ophthalmic education of many people across the world.

Comment by David — November 8, 2010

From the content point of view it look very good. Till I not seen the video.

AK Singh
FAculty Optometrist
Quality Control Manager

Comment by AK Singh — November 10, 2010

Can you explain how to do it if you use minus cylinders only

Comment by jose — November 25, 2010


Comment by DR.JAY — January 7, 2011

Fantastic! Best instruction on this topic that I have seen! Many thanks, David

Comment by DALM — January 9, 2011

the video was good and simple to understand, however we at the moment in classess work, slightly different to whats on the video, for exmple, we choose the most positive value between the two values as a sphere, then we use a negative cycl to correct for the astigmatism with axis at the positive sphere. however in this video, what type of technique is being used in the video positive cycl form or negtative, as im getting the impression its positive cycl form.

for example: we have two different meridian powers
+4.00 axis90 and +2.00 axis 180


subtract wrokin distance
thats how we work it out

Comment by waheed zaman — January 26, 2011

Thank you very much
It is very nice lecture

Comment by moha — February 11, 2011

thanks very much.i am a begining resident &i admired it very much .thanks again.

Comment by sisozizo egypt — March 16, 2011

I cannot express my great thanks for your wonderful teaching talent

Comment by abdelsattar — April 2, 2011


a small query. wud b kind of u if u cud reply…

how do u select the the axis for spherical power from which the workin distance is subtracted in case of un-rule astigmatism? is it the first one whichever gives complete bright red reflex?

Comment by raj — April 17, 2011


a small query. wud b kind of u if u cud reply…

how do u select the the axis for spherical power from which the workin distance is subtracted in case of un-rule astigmatism? is it the first one whichever gives complete bright red reflex?

Comment by raj — April 18, 2011

Thanks alot Dr. Tim. I’m an under grad and this video has become the standard study material for retinoscopy amongst all my friends. Have also seen all of your other videos. you made optha easy and interesting.

Comment by rnk — May 4, 2011

How do I get the audio portion to work? Am I required to purchase a video? Can I just buy a download?


Lynn S

Comment by Lynn Sullivan — May 23, 2011

it was a very good demo.thank u so much.but i would like to know how u would do it in a keratoconus patient and how to appreciate oil drop reflex.
thank u

Comment by sasi — June 6, 2011

Big ( Thank you ) Dr. amazing,
very interesting very nice very informant video. and for all your videos.

Comment by Dr.Anas — July 14, 2011

I’m not sure of the last two cases

Comment by hello — September 2, 2011

Brilliant lecture Dr Root. I think the best way to learn retinoscopy is using a practice model eye which you can make out of a toilet roll! Please contact me and I will send you some photos and more details.
Clive Novis (South Africa)

Comment by Clive Novis — September 7, 2011

could never have understood retinoscopy without this video..u’ve made it so understandabl that i’m so mch interested in smthn i earlier dreaded..
Today as i did retinoscopy fr d 1st time,i cn only thank u fr d knowledge u’ve given..Thank u so vry mch..lukn fwd to more of sch videos..obliged to b ur student..
al d best!!

Comment by Tulika Gupta — September 12, 2011

you are making difference to many people thank you very much i am from Egypt and i have learned a lot thank you again .

Comment by mohmedfawzy — October 24, 2011

iam an optometrist , i was see the vidoeo really iam fine . this teaching is not neglect in my life . thank u

Comment by syed abdul kader — December 26, 2011

hello doctor,

Greetings from India. Thanks for the exhaustive explanation. very easy to understand ‘FINALLY’ .i will be looking forward to see many of your videos and lectures.
Thank you

Comment by Dr.Venkatesh — March 1, 2012

i am vitreo-retina consultanat
very nice and informative lecture with easy steps and less confusion

Comment by ganesh bhamare — March 27, 2012

I,m a beginner from srilanka.i,m interesting about your explanation and need to be a professional in the trade and want some more information about retinoscopy.

Comment by ruwan janaka — August 10, 2012

How about cylinder retinoscopy.Can u explain or discuss it.
thank you

Comment by Pons Macalintal — January 8, 2013

Excellent demo

Comment by Dr. Hassan — January 21, 2013

Dear Dr. Root.

You said the word “ALONG”the meridian right? so you need to convert it to ÄXIS” so if its along 90 or @ 90 and the AXIS would be 180? am I right? I’m sorry but I’m a little bit confused, as according to the book, they use the term “@”or ÄLONG” then should convert it to axis.

Hoping for a quick respond regarding on this matter.

Best Regards,


Comment by Mark Andro Tapiz — May 29, 2013

In this video … I am using the “@” sign to mean “at.” In retrospect, perhaps I should have used the more traditional “x” sign or just spelled out “at” but I didn’t.

I wouldn’t focus on the words ALONG or AT if I were you. As long as you remember that power and axis are 90 degrees from each other, you should be ok.

Tim Root

Comment by Timothy Root, M.D. — May 29, 2013

Hello Dr Root,

Thank you so much for your AMAZING videos! They really help understand concepts from our ophthalmic technician training course!

My doctor prefers minus cylinder, do you have instructions for doing retinoscopy in minus cylinder?


Comment by Marissa — June 29, 2013

Most optometrists work in minus cylinder (which is fine). I’m not used to working in minus cylinder, however, so I don’t plan on making a minus video instruction (these videos take forever to put together). Thanks!

Comment by Timothy Root, M.D. — August 22, 2013

Thanks alot Dr Root Excellent practical demonstration for learners as well as professionals.

Comment by Dr khan — September 20, 2013

Dear Dr. Root,

Ive always believed reading up from a textbook is entirely different from whats to be practised, which is why I kept forgetting most of the things I read up prior to applying it in real life. Here, your lecture on something this interesting is as close as I could get to a practical experience. I hope to take it forward and learn the most from the foundation you’ve helped me ascertain. Thank you very much.

Akansha Sinha.

Comment by Akansha Sinha — September 26, 2013

Thank you very much doctor,,

But if i have faster and brighter reflex, is it mean i’m not far to the nuetrilize

Comment by Bader — December 24, 2013

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