What are those floaty things in your eye? - Michael Mauser
-
0:07 - 0:10Have you ever noticed something swimming
in your field of vision? -
0:10 - 0:14It may look like a tiny worm
or a transparent blob, -
0:14 - 0:18and whenever you try to get a closer look,
it disappears, -
0:18 - 0:22only to reappear
as soon as you shift your glance. -
0:22 - 0:24But don't go rinsing out your eyes!
-
0:24 - 0:28What you are seeing is a common phenomenon
known as a floater. -
0:28 - 0:33The scientific name for these objects
is Muscae volitantes, -
0:33 - 0:35Latin for "flying flies,"
-
0:35 - 0:38and true to their name,
they can be somewhat annoying. -
0:38 - 0:42But they're not actually bugs
or any kind of external objects at all. -
0:42 - 0:45Rather, they exist inside your eyeball.
-
0:45 - 0:49Floaters may seem to be alive,
since they move and change shape, -
0:49 - 0:51but they are not alive.
-
0:51 - 0:55Floaters are tiny objects
that cast shadows on the retina, -
0:55 - 0:58the light-sensitive tissue
at the back of your eye. -
0:58 - 1:00They might be bits of tissue,
-
1:00 - 1:01red blood cells,
-
1:01 - 1:03or clumps of protein.
-
1:03 - 1:06And because they're suspended
within the vitreous humor, -
1:06 - 1:09the gel-like liquid
that fills the inside of your eye, -
1:09 - 1:12floaters drift along with
your eye movements, -
1:12 - 1:15and seem to bounce a little
when your eye stops. -
1:15 - 1:19Floaters may be only
barely distinguishable most of the time. -
1:19 - 1:23They become more visible
the closer they are to the retina, -
1:23 - 1:26just as holding your hand
closer to a table with an overhead light -
1:26 - 1:30will result in a more
sharply defined shadow. -
1:30 - 1:32And floaters are particularly noticeable
-
1:32 - 1:35when you are looking
at a uniform bright surface, -
1:35 - 1:36like a blank computer screen,
-
1:36 - 1:37snow,
-
1:37 - 1:39or a clear sky,
-
1:39 - 1:43where the consistency of the background
makes them easier to distinguish. -
1:43 - 1:47The brighter the light is,
the more your pupil contracts. -
1:47 - 1:51This has an effect similar
to replacing a large diffuse light fixture -
1:51 - 1:53with a single overhead light bulb,
-
1:53 - 1:56which also makes
the shadow appear clearer. -
1:56 - 2:00There is another visual phenomenon
that looks similar to floaters -
2:00 - 2:02but is in fact unrelated.
-
2:02 - 2:05If you've seen tiny dots of light
darting about -
2:05 - 2:07when looking at a bright blue sky,
-
2:07 - 2:12you've experienced what is known as
the blue field entoptic phenomenon. -
2:12 - 2:16In some ways,
this is the opposite of seeing floaters. -
2:16 - 2:18Here, you are not seeing shadows
-
2:18 - 2:22but little moving windows
letting light through to your retina. -
2:22 - 2:25The windows are actually caused
by white blood cells -
2:25 - 2:29moving through the capillaries
along your retina's surface. -
2:29 - 2:33These leukocytes can be so large
that they nearly fill a capillary -
2:33 - 2:37causing a plasma space
to open up in front of them. -
2:37 - 2:39Because the space in the white blood cells
-
2:39 - 2:42are both more transparent to blue light
-
2:42 - 2:45than the red blood cells
normally present in capillaries, -
2:45 - 2:48we see a moving dot of light
wherever this happens, -
2:48 - 2:53following the paths of your capillaries
and moving in time with your pulse. -
2:53 - 2:55Under ideal viewing conditions,
-
2:55 - 2:59you might even see what looks
like a dark tail following the dot. -
2:59 - 3:03This is the red blood cells
that have bunched up behind the leukocyte. -
3:03 - 3:08Some science museums have an exhibit
which consists of a screen of blue light, -
3:08 - 3:13allowing you to see these blue sky sprites
much more clearly than you normally would. -
3:13 - 3:16While everybody's eyes experience
these sort of effects, -
3:16 - 3:19the number and type vary greatly.
-
3:19 - 3:20In the case of floaters,
-
3:20 - 3:24they often go unnoticed
as our brain learns to ignore them. -
3:24 - 3:26However, abnormally numerous
-
3:26 - 3:29or large floaters
that interfere with vision -
3:29 - 3:34may be sign of a more serious condition,
requiring immediate medical treatment. -
3:34 - 3:38But the majority of the time
entoptic phenomena, -
3:38 - 3:40such as floaters and blue sky sprites,
-
3:40 - 3:44are just a gentle reminder
that what we think we see -
3:44 - 3:47depends just as much
on our biology and minds -
3:47 - 3:50as it does on the external world.
- Title:
- What are those floaty things in your eye? - Michael Mauser
- Speaker:
- Michael Mauser
- Description:
-
View full lesson: http://ed.ted.com/lessons/what-are-those-floaty-things-in-your-eye-michael-mauser
Sometimes, against a uniform, bright background such as a clear sky or a blank computer screen, you might see things floating across your field of vision. What are these moving objects, and how are you seeing them? Michael Mauser explains the visual phenomenon that is floaters.
Lesson by Michael Mauser, animation by Reflective Films.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:05
Krystian Aparta commented on English subtitles for What are those floaty things in your eye? | ||
Krystian Aparta edited English subtitles for What are those floaty things in your eye? | ||
Jessica Ruby edited English subtitles for What are those floaty things in your eye? | ||
Jessica Ruby edited English subtitles for What are those floaty things in your eye? | ||
Jessica Ruby edited English subtitles for What are those floaty things in your eye? | ||
Jessica Ruby approved English subtitles for What are those floaty things in your eye? | ||
Jessica Ruby accepted English subtitles for What are those floaty things in your eye? | ||
Jennifer Cody edited English subtitles for What are those floaty things in your eye? |
Krystian Aparta
The English transcript was updated on 7/16/2015.