Determining whether a patient's transient visual deficit was monocular or binocular is often harder than it seems. Here's a helpful hint to help figure it out.

If the patient alternately covered each eye during the attack and can clearly describe what was seen out of each eye, then you have it easy. However, unfortunately many patients don't do this.

A helpful clue in this scenario is to ask the patient whether reading was impaired during the attack. If it was impaired, this suggests that the visual loss was binocular rather than monocular.


Source

Givre, S. and Van Stavern, G. "Amaurosis fugax" Up to Date. 18 Jan 2010.