How to Diagnose Amaurosis Fugax

Amaurosis fugax is a temporary loss of vision that is usually caused by a lack of blood flow to the retina. It has a highly variable presentation that usually lasts for a few minutes, although it can persist for hours.

Instructions

• 1

  Obtain the patient's history for amaurosis fugax. The onset is sudden and only affects one eye with some patients describing it as a dark shade coming down over their eye. Other patients report complete blindness, blurring, dimming and fogging in the affected eye.

• 2

  Measure the duration of the loss in vision to get an indication of the etiology. Amaurosis fugax that lasts only seconds may be caused by a papilledema but a severely atherosclerotic carotid artery may cause blindness that lasts for up to 10 minutes.

• 3

  Conduct an ophthalmic examination with particular emphasis on signs of oclular ischemia if at all possible. Abnormal findings will indicate ocular disease as the likely cause of the amaurosis fugax.

• 4

  Run laboratory tests to detect systemic causes of amaurosis fugax. These will typically include a complete blood count, blood glucose level, lipid panel and sedimentation rate. Common systemic causes include cardiac emboli, vasospasms and giant cell arteritis.

• 5

  Perform imaging tests. Carotid artery duplex scanning is useful for detecting stenosis of the ipsilateral artery and a Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) will be helpful in the case of a cerebral embolism. An angiography is the standard method for identifying carotid atherosclerotic disease.