loss of vision riding bicycle

I was riding bicycle with someone who lost vision when he went over an
extremely bumpy patch on a trail. As soon as the path leveled out a
bit, the problem disappeared but it was quite alarming when it
happened. Is there an obvious explanation for this?

On Oct 18, 4:41 pm, "Mike Tyner" <mty...@mindspring.com> wrote:
>
> It isn't a common problem. Your friend should have this investigated.
> Transient loss of vision may indicate a problem with blood circulation.
>
> -MT

Would that be a problem with someone who is fairly active? The rough
path
gave him a fairly severe shaking. I assumed the shaking caused the
temporary loss of vision. Would that be a circulation problem?

aj <(E-Mail Removed)> wrote in news:1192738702.685931.256850
@k35g2000prh.googlegroups.com:

> I was riding bicycle with someone who lost vision when he went over an
> extremely bumpy patch on a trail. As soon as the path leveled out a
> bit, the problem disappeared but it was quite alarming when it
> happened. Is there an obvious explanation for this?
>

Is it loss of vision, or loss of clear vision? If the latter, its
vestibular problems.

--
Scott
Reverse name to reply

Only if your friend could repeat the problem -- could
there be some resolution.

I think Mike is correct. If there is loss of oxygen (blood) to
the retina, a person's vision can "blank" for a short time.

This happens to pilots in high "G" pull-outs.

If this happens again, he should have this checked
by a medical doctor.

Just one man's opinion,

Otis

On Oct 18, 5:34 pm, aj <jane.ha...@gmail.com> wrote:
> On Oct 18, 4:41 pm, "Mike Tyner" <mty...@mindspring.com> wrote:
>
>
>
> > It isn't a common problem. Your friend should have this investigated.
> > Transient loss of vision may indicate a problem with blood circulation.
>
> > -MT
>
> Would that be a problem with someone who is fairly active? The rough
> path
> gave him a fairly severe shaking. I assumed the shaking caused the
> temporary loss of vision. Would that be a circulation problem?

"Mike Tyner" <(E-Mail Removed)> wrote in
news:(E-Mail Removed) :

> Pilots sometimes lose their vision in vertical acceleration, and if he's
> younger, that might be all the explanation they offer.

That's an extremely clear pooling of blood in the legs, away from the
brain, easily demonstrated in a centrifuge, and somewhat alleviated by a g-
suit. No other explanation would be necessary, or correct.

--
Scott
Reverse name to reply

"Mike Tyner" <(E-Mail Removed)> wrote in
news:y-GdnddlrY-(E-Mail Removed):

>
> "Scott Seidman" <(E-Mail Removed)> wrote
>
>> That's an extremely clear pooling of blood in the legs, away from the
>> brain, easily demonstrated in a centrifuge, and somewhat alleviated
>> by a g-
>> suit. No other explanation would be necessary, or correct.
>
> It's just bothersome that blood doesn't pool instantaneously and the
> lift wasn't constant.
>
> Probably I'm watching too much House.
>
> -MT
>
>
>

The venous side is tremendously important for cardiac output. Extended
shuttle or space station stays are particularly problematic-- No gravity-->
decreased venous pooling in legs--> increased cardiac output---> long term
decrease in blood volume.

Now, that astronaut returns to Earth, tries to stand up, and doesn't have
the blood volume necessary to feed his brain. Astronauts just can't walk
in such condition, and are often wheeled off the shuttle. They just don't
show this on TV (except for John Glenn's return!).

--
Scott
Reverse name to reply