How do you approach cases of transient monocular vision loss when initial carotid imaging and cardiac workup are unrevealing?

As you eluded, it is essential to rule out amaurosis fugax in a case of TMVL, and carotid Doppler and cardiac echo are two essential tests to evaluate the two potential sources of embolization in this setting.

I would also recommend an MRI of the brain (to check for possible evidence of other ischemic/CVA changes) and an MRA of the head and neck for evaluation of the posterior circulation (as sometimes the visual loss is actually bilateral but homonymous, and the patient only appreciate the loss in the eye with temporal loss, which is more pronounced than visual loss in the nasal hemifield).

Also, I have seen patients with rare etiologies like paraophthalmic artery aneurysm with thrombosis that was the source of embolism to the retina. Two ...