Greyout / Focus/ BlackOut

[Knite]

Just a silly graphical request.

I am not a pilot, but I have experienced the edge of a blackout due to G-Forces before. One thing I remember was that it didn't start with my vision getting dark on the edges, it more seemed like I lost some color acuity around the time that the edges of my vision lost focus, and that was before the blackout began... so that's what I'm putting as wishlist...

Current setup for G force effects = Black tunnel vision

Wish : gradual loss of color with increasing blurryness around the outside of screen (tunnel vision), then entire screen darkening.

Any thoughts? Is my memory fuzzy? I think it could look great and less "construction paper cutout" than our current method seems to for a more immersive and informative (greyout likely would likely begin slightly before current blackout range) . I also think this would look fantastic in making of AH films. Recovery from blackout would be the reverse with the screen lightening, "tunnel vision" receeding and color returning.

Thanks!

[Soulyss]

Sounds interesting, if it's more accurate then I'd give it a thumbs up.

But now I can't help but wonder what's happening physiologically that would cause those symptoms.  I understand the basics of why pilots black out under G load but why would you lose color vision first?

[Knite]

Sounds interesting, if it's more accurate then I'd give it a thumbs up.
But now I can't help but wonder what's happening physiologically that would cause those symptoms.  I understand the basics of why pilots black out under G load but why would you lose color vision first?

Actually, I can answer that =)

It's a loss of blood flowing to the eye. The eye is really 2 distinct sets of nerve clusers called Rods and Cones. Rods are very high resolution black and white recepors, and Cones are the color receptors (basically). Cones seem to need slightly more oxygen/blood flow to see properly. Since Greyout/Blackout is the removal of blood flow from the upper extremeties, Cones start losing their ability to respond before the Rods do, leaving you with the Rods signaling most of what you see. When blood flow returns, the Cones again begin broadcasting signals properly.


As far as more realistic, I just checked it on Wiki (I know, not the end all-be all of resources, but it's a start), and the entry on G-Loc : http://en.wikipedia.org/wiki/G-LOC
States that there are 4 main stages of G-Force effects, in this order :
--Greyout- a loss of color vision
--Tunnel vision - loss of peripheral vision, retaining only the center vision
--Blackout a complete loss of vision but retaining consciousness.
--G-LOC where consciousness is lost.

So apparently my memory wasn't altogether off. =)

[Soulyss]

That would certainly explain it, I knew about the rod/cone structures in the eye but I wasn't aware that the cones needed more blood to function. 

I love AH, fun AND educational.

[Knite]

That would certainly explain it, I knew about the rod/cone structures in the eye but I wasn't aware that the cones needed more blood to function. 
I love AH, fun AND educational.

Well, I could be wrong on that. I've heard two reasons for greyout, that being one of them. The other reason I heard is that because there are so many rods compared to cones in our eye, when we lose, let's say 50% blood flow, that cuts off 50% of both... we have about 7 million "cones" so we're down to about 3 to 3.5 million functioning... in terms of Rods, we've got 120 million, and they are generally considered more sensitive, so we're still down to 60 million.

That's 60 million very sensitive rods compared to 3.5 million not so sensitive cones.

That's the 2nd theory I've heard. Still no idea which one (if either) are correct.

[vafiii]

Rods and cones, man. it's all about rods and cones.

[Ex-jazz]

The Red Bull Air Racer pulling 10G's without G-suite:
http://www.youtube.com/watch?v=P46VayKmRew

I'm really wondering how these guys are seeing the world during those high G maneuvers.

[RedTeck]

I think with the Red Bull racers, its more of a high g spike than sustained high g's. I watched in that video and the pulls, like at the half cuban, only lasted about 3 seconds. The effects of a blackout can also be reduced with technique (the "hic" manuever), core strength, and the persons body type. A short hefty guy with high blood pressure is going to have an advantage over the tall lanky marathon runner with low blood pressure. An FYI, part of the agreement that comes with the Blue Angels performing at an air show is the hotel must have a gym so they can work the core. As I understand it, with abs flexed more blood gets trapped in the upper body.