1.0Glossaryhttps://www.healthbenefitstimes.com/glossaryGlossaryhttps://www.healthbenefitstimes.com/glossary/author/adminglossary/rich600338<blockquote class="wp-embedded-content" data-secret="3j4oyN2xae"><a href="https://www.healthbenefitstimes.com/glossary/visual-field-defect/">Visual field defect</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://www.healthbenefitstimes.com/glossary/visual-field-defect/embed/#?secret=3j4oyN2xae" width="600" height="338" title="“Visual field defect” — Glossary" data-secret="3j4oyN2xae" 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> A blind spot in the normal range of vision. Visual field defects caused by migraines are temporary; most others are persistent. Visual field defects have a number of possible causes. Overall narrowing of the range of vision can be caused by glaucoma (abnormal pressure within the eye). A blind spot in the center of vision may come from swelling of the optic nerve or an abnormality of the macula. Defects that affect one half or one quarter of the visual field in each eye are usually caused by strokes or tumors in the brain.