<p>There are many causes of painless loss of vision, however, it is difficult to differentiate between causes that need immediate referral to an ophthalmologist, those which can be delayed referral or those which need referral to other specialists. This article will describe some of the most common causes of painless loss of vision and the decision-making processes surrounding referral, and assist A&amp;E nurses in deciding or advising upon effective management. The article will use the classification of loss of vision illustrated in Figure 1 in order to group together and describe some of its many causes.</p>