Just so we're clear

[Hiro]

It happens when I stand up way too quickly.

yeah, that's often what triggers it.

Sometimes when I stand up too quickly, my peripheral vision will fade to black, slowly closing in toward the center of my vision until I can barely see at all. I get lightheaded and have to wait a few seconds before I can see again. It's rare but it happens.

I'm pretty sure this is what he's describing.

yep

[ikanaide]

I become unbalance too

[Hiro]

I become unbalance too

yeah, it can be a little disorienting sometimes

[Hippopo]

Mine is usually triggered by reading...  And it lasts for about an hour.

Are yours like that, Hiro? 

[Hiro]

Mine is usually triggered by reading...  And it lasts for about an hour.

Are yours like that, Hiro? 

I can't recall it particularly happening when reading, no.
you get tunnel vision for an hour straight? 

[?????]

I only feel a headrush if I stand up too quickly. My vision is fine

[Hippopo]

I can't recall it particularly happening when reading, no.
you get tunnel vision for an hour straight? 

For an hour +.  Sometimes it lasts for multiple.

My shortest episode was 30 minutes.  Generally I go completely blind before my vision starts returning.

I'm guessing you don't have it this bad. 

[?????]

For an hour +.  Sometimes it lasts for multiple.

My shortest episode was 30 minutes.  Generally I go completely blind before my vision starts returning.

I'm guessing you don't have it this bad. 

See a doctor.