1.0Glossaryhttps://www.healthbenefitstimes.com/glossaryGlossaryhttps://www.healthbenefitstimes.com/glossary/author/adminglossary/rich600338<blockquote class="wp-embedded-content" data-secret="zA3GDnCND3"><a href="https://www.healthbenefitstimes.com/glossary/afferent-pupillary-defect/">Afferent pupillary defect</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://www.healthbenefitstimes.com/glossary/afferent-pupillary-defect/embed/#?secret=zA3GDnCND3" width="600" height="338" title="“Afferent pupillary defect” — Glossary" data-secret="zA3GDnCND3" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script> /*! This file is auto-generated */ !function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document); //# sourceURL=https://www.healthbenefitstimes.com/glossary/wp-includes/js/wp-embed.min.js </script> An abnormal reflex response to light that is a sign of nerve fiber damage due to optic neuritis. A pupil normally gets smaller when a light is shined either into that eye (direct response) or the other eye (indirect response). In an afferent pupillary defect (also called Marcus Gunn pupil), there is a relative decrease in the direct response. This is most clearly demonstrated by the "swinging flashlight test." When the flashlight is shined first in the abnormal eye, then in the healthy eye, and then again in the eye with the pupillary defect, the affected pupil becomes larger rather than smaller.