视网膜中央动脉阻塞（central retinal artery occlusion, CRAO），是一种严重的眼科急症。一个眼科急诊医生如果对此病误诊、漏诊，将给病人带来无可挽回的视力损失。

顾名思义，CRAO是视网膜中央动脉发生了阻塞。视网膜内层的血液供应完全来自于视网膜中央动脉，只有大约15-30%的人还有视网膜睫状动脉供应。因此一旦视网膜中央动脉的血流中断，整个视网膜内层也就丧失了血液供应，此时一个惊心动魄的倒计时过程就开始了——根据灵长动物的实验研究，CRAO发生超过90分钟就将给视网膜感觉层造成不可逆的损伤，对于临床医生来说，这个时间是从病人发生“无痛性视力丧失”的时间开始计算的，患者就诊时往往已经过去了数十分钟，因此更加紧张。

Ocular ischemic syndrome is the constellation of ocular signs and symptoms secondary to severe, chronic arterial hypoperfusion to the eye. Amaurosis fugax is a form of acute vision loss caused by reduced blood flow to the eye that may be a warning sign of an impending stroke. Consequently, those with transient blurring of vision are advised to urgently seek medical attention for a thorough evaluation of the carotid artery. Anterior segment ischemic syndrome is a similar ischemic condition of anterior segment usually seen in post-surgical cases. Retinal arterial occlusion leads to rapid death of retinal cells, thereby resulting in severe loss of vision.