Transient Visual Loss

Consider the following qualities of the visual loss to narrow your differential:

1. Mono or binocular: Mono suggests that the issue is anterior to the optic chiasm, perhaps ocular disease including ischemia. Binocular suggests that it is more posterior including optic chiasm, tracts, radiation or visual cortex.

2. Duration: migraines may have visual symptoms associated with aura that last 10-30 minutes, whereas a thromboembolic phenomena may only be 1-15minutes, papilledema can last only seconds.

3. Presence or absence of visual phenomena
--> photopsias, which are flashes of lights with geometric shapes, have their own differential of posterior vitreous detachment, migraine with aura, retinal detachment, occipital lobe infarction etc.
-->Phosphenes are flashes of lights without structure.
--> seizures may have visual symptoms
--> lack of visual phenomena, or having shading/black/blurring might be more suggestive of retinal ischemia

4. Precipitating factors:
- neck positioning could be a factor if there is severe carotid disease
- gaze positions suggest more of an orbital mass

5. Recurrent: think vasospasm, migraine, ischemia

6. Associated sx:
--> headaches or periocular pain: think of migraine or angle closure glaucoma or GCA
--> vertigo/dysarthria/diplopia: think of vertebrobasilar disease

7. And of course past medical history should guide your differential.

(Katharine Cheung MD, 9/24/10)