The Relative Afferent Pupillary Defect

Subscribe to Resus

Get the latest updates on our Conferences PLUS our Webcasts and Education Newsletters. And it's FREE!

  • We respect your privacy
  • This field is for validation purposes and should be left unchanged.

Register Now:

Sorry, we couldn't find any posts. Please try a different search.

This is an important part of the neurological examination of the eye. The Relative Afferent Pupillary Defect (RAPD), is also called the Marcus Gunn pupil, after the ophthalmologist that described the defect in 1883. The sign causes much confusion, but in reality is a very simple sign. In summary, a light is swung between both eyes. If all is normal, both pupils will remain constricted. If there is an optic nerve lesion, both pupils will ‘paradoxically’ dilate, when the light is shone into the affected side . It is really a test for decreased visual acuity. The side of decreased acuity will see a decreased afferent feed to the brain. The RAPD is a partial lesion and thus there is still some response. If the CNII lesion were complete, there would be no reaction in the eye. Other causes of RAPD include retinal detachment and central retinal artery occlusion.


The RAPD can only be demonstrated when the swinging light test is used. This is because the dynamic dilatation of both eyes gives the diagnosis. When the light being shone into the normal eye. The afferent fibres are intact and so the information goes to the brain and returns as a direct response of pupillary constriction and a consensual response(opposite eye) When the light being shone into the affected eye. Because there is impairment of the afferent fibres, the information is not adequately fed back to the brain, so minimal information is returned back to the eyes. The result is a much reduced direct and consensual response. This in effect gives the impression of the pupils dilating.

Light in the normal eye causes constriction of both pupils, ie., direct and consensual response. Light into the affected eye – Because the afferent fibres aren’t able to transmit the same amount of information to the brain, there is no time for a direct and consensual response, so both pupils appear to dilate.

Dr Peter Kas

Emergency Physician, Educator. Key Interests: Resuscitation, Airway, Emergency Cardiology, Clinical Examination. Creator


  1. Sven on 29/09/2021 at 11:43 am

    Hi there! This blog post couldn’t be written any better!
    Reading through this article reminds me of my previous roommate!
    He continually kept talking about this. I’ll send this post to him.

    Fairly certain he’s going to have a great read.
    Many thanks for sharing!

  2. declining testosterone on 29/09/2021 at 11:49 am

    It’s amazing in favor of me to have a site, which is beneficial in favor of my knowledge.
    thanks admin

    My site declining testosterone

  3. Hi there, this weekend is fastidious for me, because this point
    in time i am reading this wonderful educational article here at my house.

    my page

  4. on 29/09/2021 at 12:07 pm

    It’s very straightforward to find out any topic on net as compared to textbooks, as I found this piece of writing at
    this website.

    my site …

  5. healthy weight on 29/09/2021 at 12:10 pm

    You got a very great website, Gladiolus I discovered it through yahoo.

    My homepage :: healthy weight

  6. weight loss diet on 29/09/2021 at 12:18 pm

    Just wanna input that you have a very decent site, I enjoy
    the pattern it really stands out.

    Also visit my blog; weight loss diet

  7. Greetings! Very useful advice within this article!
    It’s the little changes that will make the biggest changes.
    Thanks a lot for sharing!

    Here is my blog post – carb diet (

  8. good healthy eating on 29/09/2021 at 12:41 pm

    Aw, this was a really good healthy eating post.

    Spending some time and actual effort to create a very good article…
    but what can I say… I put things off a lot and
    don’t manage to get anything done.

  9. firming skin care on 29/09/2021 at 1:05 pm

    I’ve learn several excellent stuff here. Certainly worth bookmarking for
    revisiting. I surprise how much attempt you put to create the sort of excellent informative web site.

    my page firming skin care

  10. concerned hemp on 29/09/2021 at 1:15 pm

    I like this web site very much, Its a rattling nice post to read and incur information.

    my webpage – concerned hemp

  11. skin care routine on 29/09/2021 at 1:15 pm

    I like what you guys are usually up too.
    This kind of clever work and coverage! Keep up the good works guys
    I’ve added you guys to our blogroll.

    Feel free to visit my site – skin care routine

  12. small seeds on 29/09/2021 at 1:29 pm

    Of course, what a splendid website and enlightening posts, I surely will bookmark your website.All
    the Best!

    Feel free to surf to my homepage … small seeds

  13. diet plan includes on 29/09/2021 at 2:06 pm

    Thanks for one’s marvelous posting! I genuinely enjoyed reading it, you are a great author.
    I will make certain to bookmark your blog and will come
    back sometime soon. I want to encourage that you continue your
    great job, have a nice evening!

    My web-site – diet plan includes

  14. Valencia on 29/09/2021 at 2:24 pm

    I really wanted to develop a simple remark to be able to express gratitude to you for these superb tricks you
    are writing at this website. My time-consuming internet investigation has now been compensated with reliable ideas to go over with my family and friends.

    I would tell you that many of us site visitors are undoubtedly
    fortunate to dwell in a remarkable community with many wonderful individuals with helpful advice.
    I feel rather privileged to have discovered the webpage and look forward to really more thrilling times reading here.
    Thanks once again for everything.

    my blog … healthy life (Valencia)

  15. skilled drug crime on 29/09/2021 at 2:31 pm

    Admiring the hard work you put into your site and in depth information you present.
    It’s nice to come across a blog every once in a while that isn’t the same
    unwanted rehashed information. Fantastic read!
    I’ve bookmarked your site and I’m including your RSS feeds to my Google account.

    My web blog – skilled drug crime

  16. cannabis license maybe on 29/09/2021 at 2:52 pm

    Thank you, I’ve recently been looking for info approximately this subject for a while and yours is the best I have found out
    till now. But, what in regards to the conclusion? Are you positive about the source?

    Feel free to surf to my page: cannabis license maybe

  17. on 29/09/2021 at 2:55 pm

    For the reason that the admin of this website is working, no question very rapidly it will be
    well-known, due to its feature contents.

    Here is my web site personal cannabis seeds;,

  18. drug rehab centres on 29/09/2021 at 3:00 pm

    Very interesting points you have observed, regards for putting up.

    Look into my web-site :: drug rehab centres

  19. growing cannabis on 29/09/2021 at 3:15 pm

    I want to to thank you for this good read!! I absolutely enjoyed every bit of it.
    I’ve got you bookmarked to look at new things you post…

    Feel free to surf to my blog: growing cannabis

  20. growing cannabis on 29/09/2021 at 3:27 pm

    I enjoy your writing style really loving this website.

    my webpage; growing cannabis

  21. healthy eating cookbook on 29/09/2021 at 3:28 pm

    Hello, you used to write excellent, but the last few posts have been kinda
    boring… I miss your great writings. Past several posts are just a bit out of track!

    come on!

    my web-site … healthy eating cookbook

  22. on 29/09/2021 at 3:36 pm

    hi!,I love your writing very so much! proportion we keep up a correspondence extra approximately your post on AOL?
    I need a specialist on this house to solve my problem. May be that’s you!

    Taking a look forward to look you.

    my web blog: houston getting treatment (

  23. free indoor growing on 29/09/2021 at 3:48 pm

    It’s nearly impossible to find well-informed
    people about this subject, but you sound like you know what you’re talking about!

    My site … free indoor growing

  24. on 29/09/2021 at 4:09 pm

    I know this website gives quality based articles and additional stuff, is there any other web site which
    offers such information in quality?

    Feel free to visit my homepage – how to perform oral sex (

  25. foods rich in omega 3 fatty acids on 29/09/2021 at 5:18 pm

    Keep working ,impressive job!

    my website; foods rich in omega 3 fatty acids

  26. quit smoking on 29/09/2021 at 6:22 pm

    I got what you mean,bookmarked, very nice site.

    my page – quit smoking

  27. on 29/09/2021 at 6:23 pm

    Thanks for the marvelous posting! I really enjoyed reading
    it, you might be a great author. I will be sure to bookmark your
    blog and will often come back down the road. I want to encourage that you continue your great
    writing, have a nice afternoon!

    Also visit my web page:

  28. keto diet on 29/09/2021 at 6:31 pm

    I?m not that much of a internet reader to be honest but your sites really nice, keep it up!

    I’ll go ahead and bookmark your website to come back later.
    All the best

    Feel free to visit my site … keto diet

  29. skilled drug crime on 29/09/2021 at 7:20 pm

    I hardly leave remarks, however after reading through some of the comments on The Relative Afferent Pupillary Defect – Resus.
    I do have some questions for you if it’s allright.
    Could it be just me or do some of the remarks look like they
    are left by brain dead individuals? 😛 And, if you are writing at other social sites,
    I’d like to follow you. Would you make a list of the
    complete urls of all your social community pages like your twitter feed, Facebook page or linkedin profile?

    Also visit my homepage skilled drug crime

  30. growing indoors on 29/09/2021 at 9:11 pm

    Hello, you used to write great, but the last several posts have been kinda boring?
    I miss your great writings. Past few posts are just a little
    bit out of track! come on!

    My blog post :: growing indoors

  31. Thanks for some other great article. The place else may just anybody get that kind of info
    in such an ideal approach of writing? I have a presentation next
    week, and I am at the search for such info.

    My page; atkins diet weight loss protein based diet revolution diet plan surrounding atkins diet diet book

  32. portable ac rentals on 29/09/2021 at 11:31 pm

    Awesome job over again. I am looking forward for your next post.

    Check out my website … portable ac rentals

  33. portable air conditioner reviews on 29/09/2021 at 11:40 pm

    Thanks for this post, I am a big big fan of this site would like to go on updated.

    my page – portable air conditioner reviews

  34. facial care on 30/09/2021 at 2:37 am

    Very well written story. It will be helpful to everyone who utilizes it, as well as me.
    Keep doing what you are doing – i will definitely read more posts.

    Look at my web page … facial care

  35. Horacio on 30/09/2021 at 12:14 pm

    For the reason that the admin of this site is working, no uncertainty very shortly
    it will be renowned, due to its quality contents.

  36. on 01/10/2021 at 2:53 am

    Hi there to every body, it’s my first pay a visit of this website; this blog contains amazing and in fact
    fine information for readers.

    Also visit my site – keto diet (

  37. sexual communication on 01/10/2021 at 3:35 am

    If some one wants expert view concerning blogging then i advise him/her to visit this
    webpage, Keep up the good work.

    Have a look at my website :: sexual communication

  38. balanced diet on 01/10/2021 at 4:07 am

    I enjoy what you guys tend to be up too. Such clever work and coverage!
    Keep up the very good works guys I’ve incorporated you guys to

    Feel free to surf to my blog … balanced diet

  39. potato diet on 01/10/2021 at 4:25 am

    Hi there Dear, are you genuinely visiting this web site daily, if so afterward you will
    absolutely get nice knowledge.

    Stop by my homepage; potato diet

  40. Oma on 01/10/2021 at 5:49 am

    Woah! I’m really enjoying the template/theme of this site.

    It’s simple, yet effective. A lot of times it’s challenging
    to get that “perfect balance” between usability and appearance.
    I must say you have done a amazing job with this.
    Additionally, the blog loads extremely fast for me on Safari.
    Outstanding Blog!

  41. on 01/10/2021 at 6:52 am

    Article writing is also a excitement, if you be acquainted with afterward you can write otherwise it is difficult to

    my web site :: focused diets,,

  42. brace company 60403 on 01/10/2021 at 8:17 am

    As soon as I discovered this web site I went on reddit to share some
    of the love with them.

    Check out my website :: brace company 60403

  43. ways to have great sex on 01/10/2021 at 8:25 am

    I’m still learning from you, while I’m improving myself.
    I certainly love reading everything that is posted on your blog.Keep the information coming.
    I liked it!

    Here is my webpage – ways to have great sex

  44. Daniele on 01/10/2021 at 9:13 am

    I could not resist commenting. Well written!

  45. Winfred on 01/10/2021 at 9:27 am

    This piece of writing is really a fastidious one it helps new the web visitors,
    who are wishing for blogging.

  46. Victoria on 01/10/2021 at 9:42 am

    Very nice post. I just stumbled upon your blog
    and wanted to say that I’ve really enjoyed browsing your blog posts.
    After all I will be subscribing to your rss feed and I hope you write again very soon!

  47. rid belly fat on 01/10/2021 at 9:42 am

    Excellent way of describing, and fastidious post to obtain facts regarding my presentation subject, which
    i am going to deliver in institution of higher education.

    Have a look at my homepage rid belly fat

  48. on 01/10/2021 at 10:08 am

    Thanks for one’s marvelous posting! I actually enjoyed reading it, you
    could be a great author.I will make certain to bookmark your blog and will often come back someday.
    I want to encourage you to continue your great posts,
    have a nice holiday weekend!

    Stop by my web blog … carb nite solution (

  49. cannabis dispensaries-san diego on 01/10/2021 at 10:30 am

    Good ? I should definitely pronounce, impressed with your website.
    I had no trouble navigating through all tabs as well as related information ended up being truly easy to do to access.

    I recently found what I hoped for before you know it at all.
    Quite unusual. Is likely to appreciate it for those who add forums
    or something, website theme . a tones way for your customer
    to communicate. Nice task.

    Also visit my site; cannabis dispensaries-san diego

  50. Lena on 01/10/2021 at 11:32 am

    It’s a shame you don’t have a donate button! I’d definitely donate to this
    outstanding blog! I guess for now i’ll settle for book-marking and adding
    your RSS feed to my Google account. I look forward to brand new updates and will share this
    site with my Facebook group. Chat soon!

    my blog post – perfect skin care (Lena)

  51. weight watchers on 01/10/2021 at 11:32 am

    I was suggested this web site by my cousin. I’m not sure
    whether this post is written by him as nobody else know such detailed about my problem.
    You are wonderful! Thanks!

    Also visit my blog post: weight watchers

  52. Debora on 01/10/2021 at 12:12 pm

    Definitely believe that which you said. Your favorite reason seemed to be on the web the simplest thing
    to be aware of. I say to you, I certainly get annoyed while
    people consider worries that they just do not know about.
    You managed to hit the nail upon the top and defined
    out the whole thing without having side effect , people could take a signal.
    Will probably be back to get more. Thanks

  53. Marcelino on 01/10/2021 at 12:13 pm

    I am extremely impressed together with your writing abilities and also with the
    layout for your blog. Is this a paid theme or did you
    customize it your self? Either way keep up the excellent high quality writing, it
    is uncommon to peer a nice blog like this one these days..

  54. Wayne on 01/10/2021 at 2:21 pm

    Hello, I enjoy reading all of your article post.
    I like to write a little comment to support you.

  55. poor eating habits on 01/10/2021 at 3:16 pm

    It’s very effortless to find out any topic on net as compared to books, as I found this article
    at this site.

    My blog: poor eating habits

  56. Mitchell on 01/10/2021 at 3:20 pm

    Your style is so unique in comparison to other people I have read stuff from.
    Many thanks for posting when you have the opportunity, Guess
    I will just bookmark this blog.

  57. Gerard on 01/10/2021 at 3:27 pm

    I blog quite often and I really thank you for
    your content. This great article has truly peaked my interest.
    I will take a note of your site and keep checking for new
    information about once per week. I subscribed to your Feed as well.

  58. Blaine on 01/10/2021 at 3:51 pm

    Hey! I could have sworn I’ve been to this blog before but after reading through some of the post I realized it’s new to me.
    Nonetheless, I’m definitely delighted I found it and I’ll be
    book-marking and checking back often!

  59. Sean on 01/10/2021 at 3:53 pm

    I have read so many content regarding the blogger lovers except this piece of writing is truly a
    fastidious piece of writing, keep it up.

  60. Bev on 01/10/2021 at 4:40 pm

    This post offers clear idea for the new people of blogging, that genuinely how to do blogging.

  61. Melisa on 01/10/2021 at 4:48 pm

    I believe what you published was actually very reasonable.
    However, what about this? suppose you typed a catchier post title?

    I mean, I don’t want to tell you how to run your website, however suppose
    you added a title to possibly get a person’s attention? I mean The Relative Afferent Pupillary Defect – Resus is a little plain.
    You could look at Yahoo’s home page and watch
    how they create post headlines to grab viewers to click. You might add a video or a
    pic or two to grab readers interested about what you’ve written. Just my
    opinion, it could make your blog a little bit more interesting.

  62. on 01/10/2021 at 5:25 pm

    hey there and thank you for your information ? I
    have definitely picked up something new from right here.
    I did however expertise some technical points
    using this website, as I experienced to reload the website many
    times previous to I could get it to load properly.

    I had been wondering if your web host is OK? Not that I’m complaining, but sluggish loading instances times
    will sometimes affect your placement in google and can damage your quality score if advertising and marketing
    with Adwords. Well I am adding this RSS to my e-mail
    and can look out for a lot more of your respective interesting content.
    Ensure that you update this again soon..

    Here is my web site – seeds require long []

  63. cannabis license on 01/10/2021 at 5:45 pm

    After I initially commented I appear to have clicked on the -Notify me when new comments are added- checkbox and from now on whenever a comment is added I
    receive four emails with the same comment.

    There has to be an easy method you can remove me
    from that service? Thank you!

    Here is my blog: cannabis license

  64. I am just writing to make you be aware of of the outstanding encounter our princess
    enjoyed viewing your site. She realized such
    a lot of issues, which include how it is like to have a wonderful giving
    character to get the mediocre ones clearly fully understand chosen advanced subject matter.
    You really exceeded our own expectations. I appreciate you for
    displaying such great, safe, educational as well as unique thoughts on the topic to Evelyn.

    my web page freshly hatched seeds –,

  65. Debbie on 01/10/2021 at 7:51 pm

    Hello there! Do you know if they make any plugins to safeguard
    against hackers? I’m kinda paranoid about losing everything I’ve worked hard on. Any tips?

  66. Wendy on 01/10/2021 at 8:16 pm

    Hello, I log on to your blogs regularly. Your story-telling style is witty, keep it up!

  67. Gabrielle on 01/10/2021 at 8:46 pm

    What a information of un-ambiguity and preserveness of precious
    experience on the topic of unexpected feelings.

  68. Aretha on 01/10/2021 at 9:01 pm

    Thanks to my father who informed me about this blog, this web site is actually awesome.

  69. Clara on 01/10/2021 at 9:16 pm

    My family all the time say that I am killing my time here at net, except I know I am getting familiarity everyday by reading thes
    good articles.

  70. Lupe on 01/10/2021 at 9:33 pm

    Hello! Do you know if they make any plugins to help with SEO?
    I’m trying to get my blog to rank for some targeted keywords but I’m not seeing very good success.
    If you know of any please share. Appreciate it!

  71. Marc on 01/10/2021 at 9:52 pm

    An outstanding share! I’ve just forwarded this onto a co-worker who was doing a
    little homework on this. And he in fact bought me lunch simply because I discovered it
    for him… lol. So let me reword this…. Thank YOU for the meal!!
    But yeah, thanks for spending some time to talk about this matter
    here on your website.

  72. care tips honey on 01/10/2021 at 10:18 pm

    I like your writing style truly loving this site.

    Feel free to surf to my web-site … care tips honey

  73. Zachery on 01/10/2021 at 11:11 pm

    Excellent items from you, man. I’ve keep in mind your stuff previous to and you’re simply extremely fantastic.
    I actually like what you have received here, really like what you are stating and the way during which you assert it.
    You are making it enjoyable and you still take care of to stay it smart.
    I can’t wait to learn far more from you. This is actually a terrific site.

  74. Gavin on 02/10/2021 at 12:20 am

    Wow that was odd. I just wrote an very long comment but after
    I clicked submit my comment didn’t show up. Grrrr…
    well I’m not writing all that over again. Anyhow, just wanted to say superb blog!

  75. Deangelo on 02/10/2021 at 2:56 am

    I’m amazed, I have to admit. Rarely do I come across a blog that’s both equally educative and entertaining, and let me tell you,
    you have hit the nail on the head. The problem is something which not enough men and
    women are speaking intelligently about. I am
    very happy that I stumbled across this during my hunt for something relating to this.

  76. best skin on 02/10/2021 at 4:06 am

    hey there and thank you for your information ? I?ve definitely picked
    up something new from right here. I did however expertise some technical issues using this site, since I experienced to reload the site lots of times previous to I could get it to load properly.
    I had been wondering if your web host is OK?
    Not that I am complaining, but slow loading instances times will often affect your placement in google and can damage your high-quality
    score if ads and marketing with Adwords. Well I am
    adding this RSS to my e-mail and could look out for
    a lot more of your respective interesting content. Make sure you update
    this again very soon..

    my website … best skin

  77. Leta on 02/10/2021 at 4:35 am

    There’s definately a lot to learn about this subject.
    I really like all of the points you made.

  78. Yanira on 02/10/2021 at 4:48 am

    It’s nearly impossible to find experienced
    people about this subject, but you sound like you know what
    you’re talking about! Thanks

  79. Ewan on 02/10/2021 at 6:18 am

    Wow, this post is fastidious, my sister is analyzing these kinds of things, thus I am going to tell her.

  80. Clyde on 02/10/2021 at 8:03 am

    What’s up Dear, are you in fact visiting this web page regularly, if so then you will without
    doubt take nice experience.

  81. Georgina on 02/10/2021 at 9:16 am

    Hey there! I know this is sort of off-topic however I had to ask.
    Does running a well-established blog like yours take a lot of work?
    I’m completely new to blogging however I do write in my diary on a daily basis.
    I’d like to start a blog so I can easily share my personal experience and feelings online.

    Please let me know if you have any kind of ideas or
    tips for new aspiring blog owners. Thankyou!

  82. Mattie on 02/10/2021 at 9:50 am

    For newest news you have to visit web and on the web I found
    this site as a most excellent web site for latest updates.

  83. Daryl on 02/10/2021 at 10:06 am

    We’re a gaggle of volunteers and starting a new scheme in our community.
    Your website provided us with useful information to work on. You have done an impressive job and our entire community will likely
    be grateful to you.

  84. I’m not sure where you are getting your information, butt great
    topic. I needs to spend sme time learning mor or understanding more.
    Thanks for great information I was looking for this informatiion for
    myy mission.

  85. Estelle on 02/10/2021 at 11:33 am

    Hello I am so happy I found your blog page, I really found you by
    accident, while I was researching on Askjeeve
    for something else, Anyhow I am here now and would just like to
    say thanks for a incredible post and a all round interesting blog (I also love the theme/design), I don’t have
    time to read it all at the minute but I have saved it and also added in your RSS feeds, so when I have time I will be back to
    read more, Please do keep up the excellent jo.

  86. Paula on 02/10/2021 at 11:45 am

    Hello, I read your blogs on a regular basis. Your writing style is awesome, keep doing what you’re

  87. Fredericka on 07/10/2021 at 10:26 am

    Hi there friends, nice piece of writing and good urging commented at
    this place, I am really enjoying by these.

  88. Google on 09/10/2021 at 2:33 am


    Here are some of the web pages we recommend for our visitors.

  89. on 09/10/2021 at 7:21 am

    Nice post. I used to be checking constantly this weblog and I am impressed!
    Extremely useful information specially the last section 🙂 I handle
    such information a lot. I used to be looking for this particular info for a long time.
    Thank you and good luck.

    Take a look at my web-site :: kids smoking (

  90. Sheryl Deonarine on 12/10/2021 at 6:02 pm

    How do I change the background on my blogspot including sidebars?

  91. uberti.45 long colt on 13/10/2021 at 9:14 pm

    uberti.45 long colt

    […]The data talked about in the report are some of the ideal readily available […]

  92. savage 110 tactical on 13/10/2021 at 11:44 pm

    savage 110 tactical

    […]we prefer to honor many other online web pages around the internet, even though they aren’t linked to us, by linking to them. Underneath are some webpages really worth checking out[…]

  93. aa12 for sale on 14/10/2021 at 7:29 am

    aa12 for sale

    […]we came across a cool web page that you just may well get pleasure from. Take a search for those who want[…]

  94. sig p320 on 14/10/2021 at 11:56 am

    sig p320

    […]that would be the end of this report. Right here you’ll locate some web pages that we believe you will value, just click the hyperlinks over[…]

  95. mossberg mvp patrol on 14/10/2021 at 6:57 pm

    mossberg mvp patrol

    […]always a major fan of linking to bloggers that I enjoy but do not get a good deal of link appreciate from[…]

  96. munsters slot machine for sale on 14/10/2021 at 8:58 pm

    munsters slot machine for sale

    […]check below, are some completely unrelated sites to ours, on the other hand, they may be most trustworthy sources that we use[…]

Leave a Comment