In the end, you literally see Nothing. It's truly bizarre. It's not an experience I particularly want to repeat, but I'm kinda glad it happened just once, for the empathy value. It's not really something that can be effectively described if you haven't (not) seen it yourself; even now, I have trouble re-imagining the experience, 'cause my memory wants to fill in blackness or grayness or whatever. But at least in theory I now know exactly what the Nothing from _The Neverending Story_ (doesn't) look(s) like. :)
 What makes it even more bizarre is that migraine blindness is a strictly neurological effect- there's no damage to your eyes or optic nerves- which means you can get temporary blindsight. In my wife's case, this meant she managed to walk a couple blocks home from a friend's house, crossing suburban streets and so forth, totally normally, while all the while convinced that she was completely blind. Which, as far as conscious perception goes, was the truth!
This is the first time I've heard of anyone else experiencing this phenomenon besides myself. Have there ever been any long-term effects on you?
Mine is slightly different. I don't have migranes, for one. Also, in addition to experiencing exactly what you described (minus the migrane), sometimes I experience the inverse: I can no longer see whatever I look at, but I retain peripheral vision. For example, if I were to look at the "o" in the word "for," I wouldn't be able to see the entire word. I could still read, with difficulty, until the effect became so strong that reading was impossible. (I still had peripheral vision, sort of, but eventually paragraphs became unseeable rather than individual words.)
Whenever any of these things occurred, I was completely normal again within two hours. It was bizarre, and it's mystified myself and two eye doctors. It's only happened less than a dozen times, but it's been happening since I was very young, and my most recent was less than a year ago.
The "blindness" was exactly as you describe: not a blackness, but a nothingness.
Do you happen to have any more info about the condition? It's very elusive.
It's a grab bag of weird perceptual effects that can precede migrane attacks (and apparently epileptic seizures), and they can be very disconcerting if you don't know about them.
In my case (only had them once or twice), I experienced the same visual field disassociation as you did (in addition to the scintillating scotoma thing) - I could see individual things in my field of view just fine, but I could not properly combine the whole scene into a whole. Like looking at a cubist artwork - each part is reasonable but the whole doesn't fit together, or had parts missing (not holes, just discontinuities). Of course, very shortly after that started, the migrane headache arrived.
Might want to consider talking to a doctor about it; while AFAIK auras are harmless if a bit scary, if you don't have them associated with a known issue like migrane headaches, might be good to try to find out where they're coming from. Not that anyone really seems to understand the mechanisms involved.
The experience for me is absolutely identical to that of a blind spot optical illusion, except bigger and in a different area (just a bit off from the center). It's not generally obvious that there's an issue, the brain fills it in, but if I put text in that part of my vision I'll notice I can't actually read it.
I was walking the hall to my first period, mainly looking at the bland floor tiles, and didn't realize anything was abnormal. When I happened to look up at the faces of fellow students, I noticed they had no faces, just skin colored smoothness. My hands, and text on the posters on the walls appeared in my peripheral vision, but as soon as I looked directly at anything, it seemed to disappear into an average of it's surrounding colors. I didn't freak out, but calmly walked to my first period, where I was scheduled to take a test. I made way to my desk, and marveled at this oddness, but didn't say anything, until the test was passed out and I could tell it was a page of text, but, of course, the words disappeared upon inspection. I was really impressed how useless my peripheral vision was in dealing with text or faces.
I had an awkward conversation with the teacher, who I feared thought I'd invented a disorder to get out of the test, before being allowed to visit the nurse.
The condition lasted maybe an hour. The ophthalmologist I saw shortly after found nothing wrong with my retinas or eye pressure, and declared it a visual migraine and let me go, with a newfound empathy for those with macular degeneration.
Obviously no black patch or anything like that; I first noticed the missing section (before I had visual field tests done to detect it properly) while driving, stopped at a light; I rubbed my other eye momentarily, and the traffic light vanished.
You might be experiencing a migraine without headache:
My ophthalmologist detected it during a regular examination and sent out for MRI/CAT scan/spinal tap to rule out everything else, then put me on a regimen of -- oh, now I can't remember; the medicine used for altitude sickness (diamox?) and eventually "cured" me; I haven't had a recurrence since.
I guess my point is that the grandparent poster should consider seeing an ophthalmologist and/or a neurologist at their earliest convenience. (My doctor was pleased that he'd "caught it in time"; he spoke of another patient in which it had not been detected quickly enough and that person had gone blind.)
The loss of foveal vision or random patches of the visual field (as opposed to gradual-leading-to-total elimination of the entire visual field) is something I have encountered a few times. As quantumet noted, auras are kind of a grab-bag, different people can have wildly different kinds of visual distortions, and some migraine sufferers don't have them at all. I know one who gets aural (hearing) distortions instead; meanwhile, I don't get any hearing issues, and my wife becomes hypersensitive to sound but doesn't experience distortion.
Migraines, generally, like seizures, are a result of mis-fires in your brain (super simplified explanation, of course). Essentially, something goes wrong such that your brain just decides that it is in pain for no particular reason (although there are triggers, just like there are triggers to epilepsy, that set of just the wrong cascade of neurons). Auras are just another manifestation of the same thing- if the thing that goes wrong goes wrong in or near your visual cortex, you get visual distortions in addition to the pain. Eventually, your brain resets, and then things are normal again, until your brain (metaphorically speaking) tries to read out-of-bounds memory, or goes into an infinite loop, or whatever else it is (again as quantumet noted, the exact mechanism is not really all that well understood), the next time.
Side note, on how everybody's auras are a little different- we just found out about a month ago that my most common aura is blue sparkles, while my wife's is gold sparkles. We knew that we both commonly saw sparkles, just never happened to mention the color before. Also incidentally, I do get auras much more often than I progress to a full-blown migraine headache.
Since the problem is neurological, eye doctors generally won't be able to figure it out or do anything about it. Generally, because eye problems can be migraine triggers. My wife starts getting headaches if she leaves her glasses off too long, and one of the first things to check when migraine frequency increases is whether her prescription has gone out of date. Other triggers are dehydration (for her) hunger (for both of us; this is a problem for me because I don't get hungry normally, so sometimes the first indication that I need to eat today is the onset of a headache) and sleep deprivation (for both of us).
I'd like to add that I had a recent recurrence of an aura, after some twenty years! It did not precipitate in a headache, and it was the type with a zig-zag edge surrounding the blind spot: an edge of shimmering color. After it came and went, I prepared myself for a headache, but it never happened.
ps : Many thanks
 As far as I could search, it's close to sleep epilepsy.
This sounds like tunnel vision. I get that when I'm not feeling well (for example, some kind of gut disturbance).
It's probably worth clarifying what we mean by blind. The article and the parent comment are talking about having no light perception at all. However, many (I think most) people who are considered legally blind do have at least some light perception. The legal standard in the US is vision that can be corrected to at best 20/200 in the better eye.
While the eye which is closed receives – 'less attention' is the best way I can put it – I perceive blackness in that portion of my visual field.
People have always assumed that what I see out of my left eye is basically what someone would see out of a normal, healthy eye with a big black spot in the middle, but that's not it. I don't see blackness, I see nothing.
Not the same, but similar:
According to the Nobel Prize-winning research from David Hubel and Torsten Wiesel in the 1960s, the brain may only have a short window of opportunity in which to develop binocular vision, in which both eyes are used together. Their studies in cats, and many other studies since, suggest that if the developing brain isn’t exposed to overlapping images from the two eyes, it will never form the connections it needs to process a three dimensional scene
See the entire article: http://www.bbc.com/future/story/20120719-awoken-from-a-2d-wo...
["Oh, it's easy to understand the PHYSICS and BIOLOGY of color, but can the blind really comprehend the EXPERIENCE of color?", some might say. Alright, fine, shades of "What Mary Didn't Know", but I'm not keen to get into that.]
For example, attempt to describe a baseball. Descriptions invoking roundness and texture can be easily understood because the individual retains his/her sense of feel. But saying "it's white in color... white is actually the presence of all colors..." obviously doesn't work.
I'd be curious to hear an example of how you would explain color to someone who has been blind for life.
When a sound is close to you, it seems louder. When it's far away, it seems quieter. But sounds have other qualities which are perceived the same regardless of distance - pitch being the most recognizable. And a sound's pitch changes how you perceive it unconsciously - that is, there is a "qualia" to hearing a low sound vs. a high sound that cannot really be explained.
Similarly, visible objects which are close appear larger and those far away appear smaller. But visible objects have other qualities which are perceived the same regardless of distance - namely color. And an object's color also has a certain "qualia" that unconsciously affects how you feel about it.
This has the added advantage of making it easy to explain Doppler shift vs. redshift :)
But it's probably difficult or impossible to understand what the perception is like, and how rich it is, except by analogy when thinking about how they'd try to describe the senses the do have to someone that doesn't have them.
Our understanding of echolocation in bats or the magnetic field in birds is probably similar. We understand what they detect and how they detect it. But I don't think we have any understanding of what it's like to experience that perception.
Your brain is expecting certain input in given situations, and you have layers and layers of habits based on those expectations.
If you are accustomed to NOT having that input, you don't expect it. You don't fake it (imagining a black space of the size a visual field would be...), you just don't have it, and it's not a part of your interactions with the world.
If the shape of your visual field changes suddenly -- you're about to pass out and you get "tunnel vision" -- it's obvious and startling. If it changes gradually, you don't even notice; you just start hitting your head on low beams more often, or bumping into table edges as you go by, until you adjust (this is from experience...).
Blind people can have a good or bad sense of direction, just like their sighted peers. I think the device described in the article might be more useful on short distances and less relevant for knowing where your home is while you're far away from it. This because blind people don't have the visual queues to determine if they're walking in a straight line for example. Getting immediate feedback could help with such skills and learn them how to verify the signals from the device with other senses.
Sensory substitution, aka how to replace input from one sense with input from another is a quite interesting topic.
Please forgive me for the naive question, I'm probably full of misconceptions about blindness, but out of pure curiosity, how do you read and write so well without seeing? Is the technology so advanced today? Are you using a screen reader and a regular keyboard? (e.g. typing and than playing it via the reader) how do you know if you made a typo? (e.g. who's and whose sound the same)
You really didn't have any typos, and as well your indentation and styling are perfect (much better than me but I'm not a native English speaker)
Can you read and write code without seeing? Are there any blind programmers that you know of.
again asking out of pure naivety
tl;dr, I'm impressed with your reading and writing considering that you said your are totally blind, and curious how do you do it. (I always was afraid of going blind for some reason, and afraid I will never be able to write code again)
> Is the technology so advanced today? Are you using a screen reader and a regular keyboard? (e.g. typing and than playing it via the reader) how do you know if you made a typo? (e.g. who's and whose sound the same)
Yes, I'm using a regular keyboard and a screenreader. Besides speech output I use a device called a refreshable braille display which can display up to 40 or 80 characters at a time depending on the model being used. I'm sure you will find some pictures if you Google it. However, those devices are quite expensive and many blind people just use speech output. Even with just speech there are options for reading letter by letter, word by word etc. However, I see some people make much spelling mistakes because they just listen and not rreally read how a word is spelled.
> Can you read and write code without seeing? Are there any blind programmers that you know of.
Sure you can. I make a living by programming and doing web accessibility consultancy. Another nice example is the free and open source NVDA screenreader, which is developed by two blind guys.
At what speed do you replay text->audio (ie realtime, 1.5x,2x,...)?
Lastly, if you disregard price is the braille 'refreshable display' a better experience?
Approximately the speed that the guy at the beginning of this video uses: https://www.youtube.com/watch?v=92pM6hJG6Wo
> Lastly, if you disregard price is the braille 'refreshable display' a better experience?
It just what you're used to I guess, I know lots of people who can get by without one. I especially like it when doing coding and doing stuff in a terminal. Easier to see indentation, parenthesis, quotes etc.
Indeed! Have you ever tried something like the vOICe http://www.seeingwithsound.com/ ?
Yes, I have played with it. However, I'm not convinced yet if I should invest a lot of time learning it. Another useful and interesting skill is echolocation. I have used that since Iwas a child to survey my environment.
Human echolocation is absolutely balling, what else can I say?
They then take you into a series of rooms (bathroom, the street, art gallery, kitchen etc.) which are completely black. Not a shred of light. You are blind. I can't describe how it felt other than terrifying. I didn't know if my eyes were open or not. It wasn't the black that I saw when closing my eyes, or am sleeping in a dark room. It was this empty hollow of nothingness.
As someone who has always wondered what it's like to be blind then closed my eyes for a few minutes and stumbled around my home - it's nothing like that at all. I left having found a new sense of understanding for the struggles that blind and visually impaired people go through on a daily basis.
An interesting but harrowing statistic they mentioned at the end of our trip was that the majority of people go blind, instead of are born blind. And the main cause is diabetes. It's not uncommon that those with diabetes lose their sight and then their sense of touch. Imagine not being able to feel your way around after going blind.
I highly recommend the exhibition if you're ever in Warsaw, and I think they have it in a couple of other cities:
We have the ability to turn our senses off when we are going to sleep, so any "sixth sense" prosthetics should be switchable or at least not strong enough to disturb sleep.
It seems slightly cruel to me to give someone a device to augment their senses without some provision for them to continue using it if the experiment is successful.
I suppose it's also possible that Wächter didn't want to continue using / being reliant upon the belt despite the loss of the spatial sense it had provided.
I wonder how it was once he took them off.
Although having written that, I now wonder whether a person who loses their hearing might be plagued by phantom hums or such things, as can sometimes happen to hearing people when exposed to extended silence.
Describing my lack of sight is difficult, because few people have the necessary frame of reference to understand. The best way I've found to describe it is to say that I can only see one side of my nose. Now, I know the other side is there, obviously, because I can look in a mirror and see it with my good eye. But without a mirror, that side of my nose doesn't exist to my vision. --There's not a dark blob or anything like that - it simply does not exist.
It also means I have no real depth perception. I have to try and estimate the distance of an object based on what I know of it's true size - when it's moving towards me, I don't get a real sense that it's actually coming at me, just that it's getting larger at some rate. Needless to say, that makes playing games like baseball very diffciult as there is not necessarily other objects around that make it easier for me to recognize the rate at which the ball is flying towards me.
Gregor Mendel is called "father of modern genetics" for his work on plant hybridization and discoveries in the area of hereditary traits. He's called that because he described "invisible factors" producing "traits." We would now say that he discovered genes and their expression.
Around the same time Charles Darwin produced his great works on evolution. He was also essentially relying on invisible factors inherited from previous generations producing discernible traits in subsequent generations. He went beyond that and hypothesized about how constant sexual and natural selection would allow certain traits to be more common in the species as a whole.
Both of these men were essentially studying and describing genes, geneplexes & DNA. But, DNA was unknown to them. They knew that traits are handed down from one generation to another. But, if you asked them what the physical form of these traits was, they would have no answer.
DNA & Genes were not observable to them. They had placeholders in their mind. I guess they new that the seed produced by the parent plant contained the traits, but they might have also used "spirit" or "essence" as their placeholder.
We are at this stage when it comes to cognition. We don't know what a thought, memory or emotion looks like. We don't know what their physical form is. We know it has something to do with neurons and the brain, but we don't really know the how and what.
There is an obvious hole in our knowledge. It' missing in discussions like this.
It went on about some difficulties he had processing the new data. His brain had to "learn" how to see. It was so difficult that he would sometimes close his eyes and and rely on his echolocation skills to navigate.
Very interesting book if you want a first hand account of what it is like to go from being blind to being able to see. (and also about being blind)
Left eye as well, although my eye is healthy, it was closed when I was a baby so my vision never developed properly. Eye patching was tried on me as a kid, but just resulted in a cranky toddler me. It took years and years for me being able to verbalize what I could see out of my left eye--I basically have some limited peripheral vision and no central vision. My eye doctor explained that part of the issue is that peripheral vision primarily detects motion while central vision is for detail--so while I can detect motion and light, it's hard for me to put an image together.
I have so many memories of trying to read that big stupid E with my left eye and not being able to explain what I saw. (Um, there's a light on, right?)
A much younger person I know who has very limited vision (and the prospect of declining vision as she grows up) attends summer mathematics programs with children running around playing soccer and Frisbee and seems to handle that with aplomb. To not even be able to recognize shapes or moving human beings, something that the blind people I know best are still able to do, would be especially challenging.
Aside: Have you all noticed that people who have acquired profound deafness that begins in adulthood have much less understandable speech than people with normal hearing? Apparently we all rely on feedback from our own senses to keep our speech behavior within the phonologically normal range of whatever language we speak as a native language, and habit alone can't maintain the fine tolerances necessary for readily understandable speech.
AFTER EDIT: Of course anyone can experience total lack of sight simply by going into a totally unlighted place. The human eye doesn't emit vision rays, after all (even though the ancient Greeks seemed to think otherwise), so if you are where there is no light, you see nothing with your eyes. Studies on the human diurnal behavior cycle are sometimes done in deep caves with no source of artificial light.
In any case, my speech was affected in the way you describe. Most soft sounds started merging, e.g. 's', 'sh', 'tsh', etc. would all end up sounding like 'sh' coming from my mouth, and I had absolutely no idea that was the case. Similarly, I had no idea what the volume of my voice was, it'd either be really loud or really quiet, but rarely at the right level. My parents (mostly) told me I wasn't speaking properly (it took years before anybody realized I was going deaf, including myself), I ended up relying heavily on the vibrations I felt in and around my mouth/throat to correct these as much as possible.
Interesting aside to this aside, there exist implants for people who were born without a cochlea (the spiraly thing which "translates" vibrations). These implants are made of some alloy (not sure what exactly) which thankfully emulate a cochlea, but have the interesting side-effect of causing the affected people to speak with a fairly monotone and somewhat metallic voice.
I immigrated right around the "easy"-language-acquisition barrier age and frustratingly can't speak either of my languages fully right - one because of leftover accent, one because of out-of-use vocab and grammar atrophy.
“People think that deafness means silence, but they are wrong. It is a constant noise that ranges from a gentle whisper going through some cracks to a constant buzz, which is worse.”
What has always fascinated me about sight is how our brains augment and outright invent things you think you see with your eyes. It's not at all about believing what you see, but about seeing what you believe.
The Glaucoma has steadily been eating away at my retina and optic nerves over the many years. Causing blind spots to form all over my visual field. In daily life, I can't see those spots. As in, there are not actually black holes in the images I perceive. The brain somehow manages to fill in those gaps with visual information directly surrounding those gaps and combine it with what my experiences/memories tell me should be there.
It's only when I start concentrating on really small details, that these holes become apparent. Particularly when looking at small LED lights in a dark environment. The LED keeps disappearing and reappearing as I slowly turn my head in various directions. Everybody has a single blind spot like this in the center of their visual field which behaves in the same way. Imagine this, but multiplied over 60 - 80% of your visual field.
Additionally, my almost-blind left eye has caused me to lose depth perception all together. This means those fancy stereoscopic 3D things are pointless to me and one would expect I would have a hard time in traffic. Not being able to judge the distance to an oncoming car can be deadly. But again, the brain seems to draw on its memories and years of experience and somehow manages to account for the lack of depth perception. It's not perfect, but enough to cope in daily life and safely move from A to B. At least on foot, that is. I am not allowed to drive a car for obvious reasons. A moped is technically permitted, but I don't. It moves too fast for me to accurately judge my surroundings in time. The same even goes for a bicycle. I only ride those in daylight. Not at night.
As far as blindness goes, I've had this once. As a kid, I fell out of a tree and landed flat on my back. For the following 45 minutes I was completely blind. It freaked me out to no end, as I was terrified it would not go away. Luckily it did. Not looking forward to that again!
I wonder if such a phenomenon occurs with people who lost sight during their life and aren't blind by birth, where the brain fills in the blanks based on memory.
My right eye is my "main" eye (95%) and my left eye just submits the missing parts from the left that my right can't see because of the nose being in-between.
I always have the right side of my nose in my field of view, except that at the same time it's somehow not there. Like 50% opacity. The left side of my nose isn't visible.
When I "hide" a finger behind my nose for the right eye and look in it's direction it's gone. When I stare straight forward, it appears again.
(My) vision is weird :).
> I see what sighted people describe as "white". When I ask a sighted person what they see out of their elbow they typically get it. They see "nothing", but if pressed will usually say "static" or "white".
"you have to pump the pressure up in the eye to about 6x normal in order to cut a good flap, as you can't cut an accurate flap in a floppy eye. The pressure is actually higher than your blood pressure, so the eye stops perfusing with blood, and you go temporarily blind."