suleimaan,
It is most likely that what you are observing is the result of any one
or more of a number of other factors, rather than just the fact that
someone has been asleep or has become sleepy.
One reason people may get bloodshot eyes is not BECAUSE they are
drowsy, but rather, they are drowsy and have bloodshot eyes because
their body is desperately in need of sleep.
From Prevention.com's Health Center topic "Bloodshot Eyes":
Diagnosis:
"As eye problems go, bloodshot eyes are easy to self-diagnose: The
tiny network of blood vessels on the surface of your eyeballs (barely
noticeable, most times) are swollen and your eyes are red. Anything
that irritates your eyes can leave them instantly bloodshot: Wind.
Crying. A smoke-filled room. An allergic reaction to pets. Mold. Even
troublesome makeup..."
"Prevention:
Know your allergies and usual irritants, and steer clear. Drinking too
much alcohol can also cause the blood vessels to dilate and redden,
says Anne Sumers, M.D., an ophthalmologist in Ridgewood, New Jersey,
and a spokeswoman for the American Academy of Ophthalmology..."
"Treatment:
To shrink those vessels and get the red out, follow these tips:
- Chill. Applying a cold compress to your eyes for 30 minutes...
- Artificial tears...will lubricate and remoisten, ease that stinging
feeling and clear up the underlying irritation that makes your eyes
red...
- If you wear contacts, rewetting drops will...serve the same function
as artificial tears..."
"When to See a Doctor:
If your eyes are still red after a day, see your doctor. Blood-shot
eyes may be a sign of a foreign body trapped in your eye or
allergies..."
http://web.archive.org/web/20011008051525/www.prevention.com/cda/finder/1,1345,1807,00.html
From Vitamin For Life's section on "Eye Problems":
"Causes: A great many factors can contribute to visual problems
including nutritional deficiency, alcohol, drugs, physical strain,
dental problems, environmental pollution, harmful lighting, and
emotional stress. Many cases of eye disturbances and vision loss are
signs of disease elsewhere in the body...
red, swollen and/or watery eyes may be an indication of allergies..."
http://www.vitaminforlife.com/eye_problems%20disorders.htm
From All About Vision's "Ask The Eye Doc: Your Questions About Contact
Lenses":
"Q: I recently have started to wear my contacts again after not
wearing them for three or four months (I've just been wearing my
glasses). My eyes keep getting really bloodshot with them in. Is this
an issue, or is it just my eyes readjusting to the contacts? My eyes
get really "veiny," so to speak. — B.V., Idaho
A: Bloodshot eyes are a sign that something is not right. It could be
as simple as a solution allergy or dirty lenses. But it could also be
a sign that your corneas are not getting enough oxygen. Go see your
eyecare practitioner and find out why your eyes are so red! — Dr.
Dubow"
http://www.allaboutvision.com/askdoc/contact-lenses.htm
From All About Vision's "Ask The Eye Doc: Your Questions About
Computer Vision Syndrome":
"Q: The whites of my eyes are not white. They often become red when I
work hard (such as read a book or use a computer). I am 39 years old.
I'm Thai, but now I stay in Belgium to study. Could this be caused by
the change in climate? Should I go to buy eye drops? — R.M., Belgium
A: Your redness could be a sign that you are having trouble focusing
comfortably. Have your eyes examined to see if you should wear glasses
to alleviate near vision stress. It is not a good idea to use
over-the-counter eye drops on a regular basis without talking to your
eye doctor first — some of them are addictive and can have other
unwanted effects. — Dr. Dubow"
http://www.allaboutvision.com/askdoc/computer-vision-syndrome.htm
"10 visual clues that your body needs help", by Donovan Webster, Men's
Health (June 5, 2002):
"What you see: Your eyes are bloodshot.
What it might mean: Yeah, we know the obvious reasons. But it also may
mean you're taking too much aspirin for those repeated hangovers.
"Aspirin slows clotting and thins your blood, and that ends up
flooding the small vessels in your eyes," says Dr. Monica."
http://my.webmd.com/content/article/1685.53223
Search Strategy
reasons "bloodshot eyes"
://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=reasons+%22bloodshot+eyes%22&btnG=Google+Search
Before Rating my Answer, if you have questions or need additional
information, please post a Request for Clarification, and I will be
glad to see what I can do for you.
I hope this Answer provides you with exactly the information you
needed!
Regards,
aceresearcher |
Request for Answer Clarification by
suleimaan-ga
on
22 Nov 2002 00:05 PST
Hello aceresearcher, thanks for taking my question and I appreciate
all the research you have done in the area of bloodshot eyes.
My questions remain unanswered, though. Let me expand on them for
clarification of what information I need.
1. When people are sleepy, or when awoken prematurely from a sleep,
they have red eyes. Why does the body react to these states by
engorging the eyes with blood? What causes this reaction in the first
place?
2. What happens to eyeballs when someone is asleep? Now I've noticed
that they roll back and face inwards. Do they also get engorged with
blood? If so, I assume this is related to why interrupting someone's
sleep results in their waking up with bloodshot eyes.
I have tried to look for research papers related to these topics, but
couldn't find any. I don't expect it to be a heavily researched area
in the scientific community, but I do expect there exists at least
some work related to these topics.
(Just as a side note, one of the reasons I want this information is
because I need to understand the possible dangers of vasoconstrictors
to the eyes.)
|
Clarification of Answer by
aceresearcher-ga
on
22 Nov 2002 00:13 PST
suleimaan,
I'm not clear on what you're saying about vasoconstrictors. Are you
saying that you are going to be using them in your eyes?
aceresearcher
|
Request for Answer Clarification by
suleimaan-ga
on
22 Nov 2002 00:19 PST
Aceresearcher, the vasoconstrictors was just an irrelevant note, you can ignore it.
I look forward to your answer clarification.
|
Clarification of Answer by
aceresearcher-ga
on
22 Nov 2002 00:27 PST
suleimaan,
I reviewed quite a few resources in putting together your answer. I
was also unable to find any references to people's eyes becoming red
BECAUSE they were sleepy or being prematurely awakenened from sleep.
This is because that is *not* the biological mechanism that is causing
the bloodshot eyes.
What is causing the bloodshot eyes is either eye strain and fatique
from being awake for too long a period without any sleep, or from
being awakened prematurely when the body still has not yet received
enough sleep.
Again, before Rating my Answer, if you have questions or need
additional
information, please post a Request for Clarification, and I will be
glad to see what I can do for you.
I hope this Answer provides you with exactly the information you
needed!
Regards,
aceresearcher
|
Request for Answer Clarification by
suleimaan-ga
on
22 Nov 2002 00:47 PST
Aceresearcher,
I don't mean to be annoying, but I still don't have my answer! For
example, I asked why eyeballs get red when someone is prematurely
woken from sleep. You answered below by saying: "What is causing the
bloodshot eyes is ... from being awakened prematurely when the body
still has not yet received
enough sleep."
That's not an answer-- that's a restatement of my question. Do you
see what I mean??
_________________
What is causing the bloodshot eyes is either eye strain and fatique
from being awake for too long a period without any sleep, or from
being awakened prematurely when the body still has not yet received
enough sleep.
|
Clarification of Answer by
aceresearcher-ga
on
22 Nov 2002 01:28 PST
suleimaan,
I'm sorry, I misunderstood that you were asking "When people are
sleepy, or when awoken prematurely from a sleep, they have red eyes.
Why does the body react to these states by engorging the eyes with
blood?"
My reply was that the body is NOT engorging the eyes with blood as a
REACTION to the states of being sleepy or being awakened prematurely
from sleep.
What IS happening is vasodilation -- expansion and enlargement of the
blood vessels in the eyes, thus making the blood in them more visible
-- caused as the body's reaction to --> reduced levels of oxygen in
the eye tissues. <-- This reduced oxygen is often caused by lack of
sleep and eye strain, and sometimes by other triggers such as
allergies.
While a person's eyes are closed in sleep, the eyelids act as "closed
windows", permitting the eyes to retain and replenish the oxygen in
the tissues of the eye. Because the windows are closed, very little
oxygen is able to escape.
When the eyelids (windows) are open for long periods of time, that
oxygen escapes faster than the body can replenish it, just as cool air
escapes through an open window faster than an air conditioning unit
can create more cool air.
Thus, the body signals the blood vessels in the eye to open wider, so
that more oxygen from the blood can get out into the eye tissues. When
that happens, the blood vessels become more prominent and enlarged,
making the blood in them more visible, and causing the red tinge to
the eyes.
From the Frontiers in Bioscience website:
"Vascular Reactivity following Ischemia/Reperfusion", by Joseph N.
Benoit & Mark S. Taylor, Department of Physiology, University of South
Alabama College of Medicine (Received 4/19/97; Accepted 4/30/97;
On-line 5/15/97)
"The physiological role of the resistance vasculature in the
regulation of organ blood flow is well documented. In general, factors
that relax vascular smooth muscle increase blood supply while factors
that contract vascular smooth muscle reduce organ perfusion. The
balance between vascular relaxation (vasodilation) and vascular
contraction (vasoconstriction) is carefully maintained in the resting
organ such that resistance to blood flow and organ perfusion are
maintained relatively constant. Any disturbance that alters this
balance raises or lowers organ blood flow."
http://www.bioscience.org/1997/v2/e/benoit1/htmls/3.htm
In this case, the "disturbance" is the lowered oxygen level caused by
the eyes being open for too long a period of time, allowing oxygen to
escape from the eye tissues faster than it is released into the eye
tissues from the blood vessels in the eye, thus causing the body to
trigger enlargement of the blood vessels so that oxygen will perfuse
the eye tissues more quickly.
Search Strategy
"mechanism of vasodilation"
://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=%22mechanism+of+vasodilation%22&btnG=Google+Search
Again, before Rating my Answer, if you have questions, please post a
Request for Clarification, and I will try to answer your questions.
I hope that this Clarification has provided the information that you
seek.
Regards,
aceresearcher
|
Request for Answer Clarification by
suleimaan-ga
on
22 Nov 2002 12:44 PST
Very interesting. Where did you get this information? I'd love a
link if you have one. (The link you listed isn't where you go thte
information about eyes specifically is it? I couldn't tell, as the
jargon was heavy.)
I am a confused though, about one thing. This explanation would sovle
the mystery of drowsy people's eyes redenning. But why is it that
when I wake someone up suddenly, they always have red eyes? I've seen
this in many people so I doubt it's a symptom of a problem.
Perhaps a little more explanation of what you describe as a "closed
window" would help. Is it because in this "closed window" process you
describe, the reason that oxygyn can be easily replenished is simply
because, well, under the eyelid covers the eye vessels are expanding
and filling with blood? In other words, the exact same thing happens
whether you actually sleep, or try to fight off sleep-- your vessels
enlarge to go through the daily cycle of getting more oxygyn.
|
Clarification of Answer by
aceresearcher-ga
on
22 Nov 2002 15:47 PST
suleimaan,
You are right, the last article I quoted is from a medical journal,
and it is extremely jargon-heavy. That may be fine for doctors, but
for those of us who have not formally studied "medicalese", it's a bit
much. I created the "windows" analogy myself in the hopes that it
would enable you to better understand the mechanism of the body that
is causing the reddening of the eyes.
At this point, I feel that I have provided you exceptional value for
your fee. I really don't know what else I would be able to add the
Answer.
I appreciate your business, and hope that you feel you understand much
better the reasons that people get bloodshot eyes.
Thanks very much!
aceresearcher
|
