Eye Exam Tricks for Tricky Patients

This video discussed advanced eye tricks you can perform on those “difficult” patients (malingerers, neuro disorders, and myasthenia gravis). This was recorded at an ophthalmic tech conference several years ago, but I’ve recently updated the slide-graphics and cleaned up the audio. Enjoy.


TwentyEyeTricks.m4v (124 mb)

Screenshots from this video:
(comments below)

Eye tricksNear vision
The techniques for confirming fictitious blindness are discussed, including the handoff and shake.

optokinetic drumloose lensThe optokinetic drum and flag are used. Most people believe that your vision must be 20/200 or better to see optokinetic nystagmus.

ProprioceptionPinhole PAM
Finger touch proprioception testing is shown. The pinhole PAM (potential acuity meter) test is then demonstrated (very useful before cataract surgery).

Entoptic phenomenonPencil Fields
The entoptic phenomenon (Troxler fading or Purkinje effect) is shown. Then pencil field testing to determine macular sparing lesions.

Myasthenia Upgaze TestMyasthenia IcePack testMyasthenia Gravis can be detected with the upgaze test. The ice-pack rest test is shown as well.

Ocular Dominance Test
Determining the dominant eye before surgery with the “ocular dominance test”


Dr. Timothy Root is a practicing ophthalmologist and cataract surgeon in Daytona Beach, Florida. His books, video lectures, and training resources can be found at:


  1. Yep, the “entoptic phenomenon” it is. I couldn’t remember the name or find it anywhere online when I prepared the lecture. It has also been described as the “Troxler’s fading phenomenon.” Thanks for the comment!

  2. excellent work
    I need your permission to use your anatomy video in my class at the ophthalmology department, faculty of medicine, Cairo university, Egypt.
    I must congratulate you on the innovation, dedication and your teaching style. very inspiring indeed.
    wishing you all the best and thank you.

  3. I’m looking forward to buy your book in order tu support your hard work.

    All the stuff published here is extremely useful, and i really aprecciate it.

    Thanks to all the people who made this!

  4. Great stuff – I plan to study medicine and wouldn’t have particularly have gone to Ophthalmology but I am glad to have come across it. Interesting and fun stuff.

    @Miss Marlene M.D – it is very stupid to post your site on this one promoting a subscription service for Medical Advice. Not only is it annoying, it promotes self diagnosis which in most cases can and will lead to further problems.

    Respect this as an Educational free source of information.

    Great stuff.


  5. Dr. you know your truly great! I wish your one of my professor you did an excellent teaching skills, its easy to understand and remembered. Your videos really really help me a lot, for me your much easier to understand than books..Please post more videos in the future. I’m so happy to find your website. 🙂 thanks a millions….. keep up the truly helpful works.

  6. hi,
    i love your lectures and your teaching style
    i have given the presentation on anatomy of eye and retinoscopy in my clss room in front of my all senoir teachers and i got help from your lactures.
    my all teachers liked my presentation and i got fully marks how i tell that to which extent i was happy just sying thank u de tim root thanks a lot.
    uzma sattar
    2nd yr optometry student
    king edward medical college

  7. U have truely amazing teaching skills Dr. Root sir! ophthalmology was never so easy ..will definetely buy your book as appreciation and respect! Please do visit India ..


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