Back in the day, I used to do a lot of CAD drafting.

There is a well known phenomena whereby your ability to see mistakes, errors, omissions or plain nonsense in your drawing diminishes sharply after working more than a couple of hours on the same drawing or draft.

Our engineering department even had a policy, that required every drawing, no matter how simple, had to be reviewed or "Redlined" (used a red marker on a printout to circle mistakes) by at least one peer drafter before submitting it to your supervisor, This saved a lot of embarrassment to everyone, especially the company (it saved a lot of money too) since simple mistakes were caught even before hitting version control or structural assessment, even production line assembly, let alone the final customer.

Most of the errors caught by peer re are simple, basic omissions like a missing dimension, missing notes boilerplate required by specification, etc. Sometimes glaring errors are caught like personal work-notes or calculations making it to the final document, duplicating sections of the drawing, etc... however the drafter that had been working on the drawing was simply "blind" to the error until someone else pointed it out.

Also, incidence of this is noticeably higher when working on a computer (v. gr. CAD Drafting) vs doing "old school technical drafting" by hand on paper using a drawing board.

Quite frequently, simply printing or plotting your CAD draft to paper, will make you see and catch some errors, invisible to you on-screen, but a "fresh pair of eyes" will catch some that you yourself can't see even on paper.

This also known to happen in other professions that require working for extended periods on a computer document, for example, Software programmers, lawyers, technical writers, etc.

In spanish we call this phenomena "Ceguera de taller" literally "Workshop blindness" however my research (below) shows it does not translate well to english.

I thought of "Mental fatigue" however I don't think it conveys the same meaning, since mental fatigue reduces your overall awareness and acuity, and you would be blind to other's mistakes on a similar drawing or document, however (surprisingly) if you look at a document that you didn't work on yourself, you'll notice immediately any mistakes even if you have just committed them on your own work.

I came up with 3 alternatives for a literal translation (Workshop Blindness, Drafter's Blindness, and Drafter's fatigue) and tested them using Google's N-gram viewer, but none of them yielded any results, so they are probably meaningless or nonsense. Ceguera de taller, however, is widely used in spanish since around the 70's which matches the time period when PCs became affordable. so, in short:

What would be a well understood term or idiom for the inability to see your own mistakes or omissions after working for some time on the same document.

Many thanks to everyone for all the wonderful and enlightening anwers! I tried several in actual conversation and tunnel vision required the least explanations, although several ideas here work in different situations. Like "Im having tunnel vision issues with this document” when explaining I am having the condition, or the very friendly, funny and kinda ice-breaker captain obvious! Again, thank you to this wanderful community

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    +1 Or not seeing the incredible goof on your income tax form, which is obvious to your spouse after a one second glance.
    – ab2
    Commented Oct 11, 2017 at 23:17
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    Proofreading your own writing has similar problems. Once you've read something, your mind starts to see what it thinks ought to be there, making it hard to catch errors.
    – Xanne
    Commented Oct 12, 2017 at 0:28
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    Short answer, there is no convenient English expression for this. Blindness would be understood, but not 'workshop blindness'. You could say something like, "I've been looking at this so long, I've become blind to my own errors" and you would be understood by an English audience.
    – MMAdams
    Commented Oct 12, 2017 at 15:11
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    This is related to, though obviously not the same thing as, semantic satiation.
    – Marthaª
    Commented Oct 12, 2017 at 16:57
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    This is a well-researched word request.
    – MetaEd
    Commented Oct 16, 2017 at 16:35

12 Answers 12


Consider calling it tunnel vision.

Tunnel vision metaphorically denotes the reluctance to consider alternatives to one's preferred line of thought; instances include physicians treating afflictions, detectives considering crime suspects, or anyone predisposed to a favored outcome. The common way to solve this problem is a second opinion, that is, getting somebody unrelated to the original investigation to look at it from the beginning, without the same biases and preconceptions. - wikipedia, emphasis mine

In your example, the reluctance isn't a matter of conscious choice; it's a form of cognitive inhibition caused by too much focus on particular details.

Here's an example of the term used in a context not too dissimilar to the one you described:

What to do about an excess of focus? Kamal Gupta suggested: "It is called 'Tunnel Vision'…. The solution is not difficult. Management has to take a break, like once in a quarter, to take a look at the big picture. - James Heskett, Is Too Much Focus a Problem?

You'd say that after working on the draft for too long, people can develop tunnel vision.

  • 1
    Hmm. I can see this working. Tunnel vision normally implies losing sight of a periphery and only being able to see what's directly in front of you, as if one were in a tunnel.
    – psosuna
    Commented Oct 12, 2017 at 19:36
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    To be precise this is the exact opposite, you see the whole picture or what you think should be there but can't see what is right in front of you. I've experienced tunnel vision when fatigued; if someone is driving they can see what is in front of them but are not prepared for certain emergencies. As a programmer I've experienced what the OP has detailed which is the exact opposite, which is missing a detail you are looking right at.
    – Quaternion
    Commented Oct 13, 2017 at 19:39
  • @Quaternion In the OP's case, though, the things missed (errors, missing details, too much detail, etc) were peripheral to their primary focus, which was the construction of ('new') technical content.
    – Lawrence
    Commented Oct 13, 2017 at 21:44
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    Perhaps. The cases I'm thinking about in drafting is missing a dimension for a wall (although you could easily infer the missing dimension from the opposite walls and scale) as well as code violations. If someone were to point at a fault and ask the author is this in code (when it is not) they will probably say "no" but somehow until that happens everything looks great. The inferable missing dimension can't be seen to be missing and the code violation which would be noticed right away if some smug person walked by and pointed sharply at the spot, but otherwise are invisible.
    – Quaternion
    Commented Oct 13, 2017 at 23:30
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    I think I may be being too literal. This is a complex issue demonstrated by the fact that the idea isn't easily expressed in common words. If someone said "I have tunnel vision look my code over" I would understand what they meant... and understanding the meaning and intention is more important that criticizing the words individually, in realizing that I would understand this in context +1.
    – Quaternion
    Commented Oct 13, 2017 at 23:34

In British English, can't see the wood for the trees

to be unable to understand a situation clearly because you are too involved in it

Cambridge Dictionary

For example:

"I've been working on this for 6 hours now, and at this point I can't see the wood for the trees"

I'm told this is "can't see the forest for the trees" in American English.

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    This has a subtly different meaning than what the OP describes, in that "missing the forest for the trees" implies, specifically, that your attention is so focused on details that you can't see the big picture. So it's about big picture mistakes. In workshop blindness, your mistake may be missing a detail that you ordinarily would catch.
    – Jonah
    Commented Oct 12, 2017 at 15:35
  • Exactly @Jonah. The common expression given here does not always apply to the situation of the question. Commented Oct 12, 2017 at 16:14
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    @Jonah "WHY IT’S SO HARD TO CATCH YOUR OWN TYPOS" describes a similar phenomenon. He uses the phrase "blind to details". Commented Oct 13, 2017 at 1:49
  • AmE: "Can't see the forest through the trees"
    – AAM111
    Commented Oct 14, 2017 at 21:11
  • @OldBunny2800 I'm in the US, and have heard "can't see the forest for the trees" many times, but never "can't see the forest through the trees". And everything I tried on Google Ngram (though I can't fit the whole phrase) suggests "for" is many times more frequent.
    – aschepler
    Commented Oct 15, 2017 at 1:17

I believe this could be an example of directed attention fatigue. It sounds like a perfect match for causing the mental blind spots that people develop after several hours working on a specific task. I wouldn't call this a well-known phrase, but it's rather self-explanatory and I would expect it to be understood.

The gist of directed attention fatigue is that your brain tires from constant focus, and it starts to either under-compensate or over-compensate for distractions. Under-compensating would be seen as losing the ability to ignore things and losing focus. Over-compensating would be seen in what you describe - ignoring details that shouldn't actually be ignored and forgetting to do things.

Looking at an FAQ on the matter, I grabbed the section on 'thinking' symptoms of directed attention fatigue.

We may have trouble focusing, leave things half done, forget things, lose things, find it hard to think, get confused more easily, think less creatively. Or we may get stuck on certain ideas, thoughts.

Looking more into related topics like the Stroop effect, I see an underlying emphasis on the fact that sustaining attention is mostly a battle of removing unwanted distractions, external and internal. There really aren't many people who can actually focus for extended periods of time without suffering performance-wise and developing weird mental blind spots. Most studies I found did note that even a 20-minute break could restore this mental ability and that a good night's sleep was nearly guaranteed to do so.

As to why this might be worse when using a computer as opposed to something more 'real', I can only suggest that computers tend to be placed in environments which are more distracting (denser placement of desks, the sound of typing, the whir of fans, etc.) or that computers are themselves more distracting (what with screen flicker and the internet itself.)

  • Amazing research! Thank you! directed attention fatigue is quite self explanatory, and an accurate scientific term too. Perhaps not as metaphorical as workshop blindness. I remember reading a paper some time ago, on the subject of cybernetics, ergonomics and human usability designs. And this kind of fatigue becomes a major factor that needs to be designed for in cockpits and vehicle control interfaces where the pilot is expected to be at the helm for extended periods of time
    – hlecuanda
    Commented Oct 12, 2017 at 16:57
  • This phrase hardly conveys humanity. "Directed attention fatigue" sounds like how your robotics vendor might explain erroneous behavior in a machine.
    – user261642
    Commented Oct 12, 2017 at 17:48
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    Nonetheless, this is the correct scientific term to describe a particular class id of cognitive inhibition as @Lawrence mentions in his answer. After reading the wonderful linked articles here, I'm sure Directed Attention Fatigue defines what I could only describe as personal anecdotes in my question. This answer provides a lot of insight and reference to the issue at hand. Thank you so much
    – hlecuanda
    Commented Oct 12, 2017 at 18:11
  • This was the first term I thought of, but it's not a perfect fit. It generally includes a much wider range of symptoms, and isn't document-specific. That is, someone suffering from this won't just miss errors in the thing they've been working on, they'll also miss social cues, have difficulty making plans, and exhibit a host of other symptoms. Also, treatments that help with DAF (a break to meditate in the garden and regular sleep, for example) won't necessarily let you see your own work clearly enough to be an effective editor in the same way that the pure passage of time does.
    – 1006a
    Commented Oct 15, 2017 at 12:03

A phrase that I often hear – and use – in exactly this context is “Here, look at this; I need a fresh set of eyes on it.”

I work in Information Technology, and part of my job is to write code. Often, I will have been grinding away at a chunk of code for so long that I won’t see obvious logic errors, and can’t figure out why I’m getting incorrect results. That’s when I generally call a colleague over and use that phrase (or, a colleague will call me over and use it). Almost invariably, the “fresh set of eyes” will spot the problem immediately.

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    Indeed, the ironic cure for blindness is a fresh pair of ryes. It is a common and universal idiom. And also it is of those extremely rare idioms that workacross language barriers even being literal translations
    – hlecuanda
    Commented Oct 13, 2017 at 5:44
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    I prefer whole wheat.
    – Hot Licks
    Commented Oct 14, 2017 at 1:06

Edited thanks to 1006a, who pointed out that "gloss over" for eyes might be an eggcorn for the intended phrase.

An idiom comes to mind. Sometimes, when ultra-focused on a task for a long time, and after the mental fatigue kicks in, we usually say that someone's eyes are glazing over. As in, they're beginning to develop a gloss or glaze over them that's hazing and obfuscating objects in sight.

When people's eyes glaze over, the connotation is that they are mentally spent, and unable to react. This can also be said of people whose minds have taken them somewhere else, as is the case of people who are sleeping with their eyes open, people who are under the influence of something, or people who are so exhausted that their responses to stimuli are minimal.

  • This is much closer to the concept I am trying to convey. I've heard that idiom before but never in a work related environment. It was more related to mental acuity being deminished by external factors like drugs or being in love (pretty much the same thing).. thx!.
    – hlecuanda
    Commented Oct 11, 2017 at 22:53
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    I've definitely used it before in a work environment. Something like "Ugh, I've been looking at this spreadsheet for hours! My eyes are glossing over. I'm so tired..."
    – psosuna
    Commented Oct 11, 2017 at 22:58
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    Normally, one might gloss over things, but eyes glaze over.
    – Lawrence
    Commented Oct 11, 2017 at 23:12
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    An eggcorn is essentially when something like a malapropism makes it into more widespread use, generally because the incorrect version "makes sense" to the user(s). If you are correct about this being a common-enough variant, you should include a citation or examples of some sort. Outside support usually makes an answer better, and is especially important if you're making a case for something that might be unknown or controversial. You could also edit your answer to include the more common variant, which should be easier to support with a definition.
    – 1006a
    Commented Oct 12, 2017 at 16:08
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    Thanks for the info. I actually did not know the word eggcorn at all. It makes sense for this to be the case. I'll edit my answer to use the more common term.
    – psosuna
    Commented Oct 12, 2017 at 16:45

Consider using the term snow-blindness in a metaphoric sense.

The literal sense is as follows:

Snow blindness is a painful, temporary loss of vision due to overexposure to the sun's UV rays. - Wikipedia

Snow-blind adjective Temporarily blinded by the glare of light reflected by a large expanse of snow. - ODO

The metaphorical sense takes the idea that staring at something for too long can cause someone to stop being able to see what they are looking at.

Here's an example of someone picking up this sense of the term:

Writer’s Blindness (like snow blindness except pertaining to your words!)

I was searching around this morning for a phrase to describe the feeling where you’re reading over your umpteenth edit of a manuscript you know off by heart and you’re not even seeing the words anymore.

- Angela Misri


"Myopia" is a common metaphorical term for this. Nearsightedness -- being too close to something to see it clearly.

  • For myopia, perhaps they're too close to see the bigger picture. (The small/'near' picture is clear for the nearsighted.)
    – Lawrence
    Commented Oct 12, 2017 at 1:27
  • From my research myopia, when used metaphorically, means you are focused on the small details and not the big picture. But it doesn't reference the fact that this condition is specifically brought on by working on a project too long and therefore losing the ability to notice errors.
    – KumaAra
    Commented Oct 12, 2017 at 3:22
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    Being myiopic myself I get why you would use the term for this case. However being myiopic or "shortsighted" I believe has a stronger connotation to the ability of making wise decisions, or fail to account future consequences of your choices. Indeed metaphorically you can't see into the futur3s but I believe it would be too forced to fit withing my intended meaning.
    – hlecuanda
    Commented Oct 12, 2017 at 17:02
  • "being to close to see" occurs only in Hypermetropia, not Myopia. Commented Apr 22, 2021 at 13:26

Inattentional blindness, also known as perceptual blindness, is a psychological lack of attention that is not associated with any vision defects or deficits. It may be further defined as the event in which an individual fails to perceive an unexpected stimulus that is in plain sight. When it simply becomes impossible for one to attend to all the stimuli in a given situation, a temporary blindness effect can take place as a result; that is, individuals fail to see objects or stimuli that are unexpected and quite often salient.

From Wikipedia.

"Inattentional" blindness was coined in 1992, but the alternative "perceptual" blindness has ngram results going back to 1895. Neither term is directly related to computers, but I believe it's the same phenomenon.

Personally, I use the term task blindness, but this has no ngram results and few regular google results. People might understand what you mean if you use it, but it doesn't appear to be a common phrase.

  • +1, I searched for the term "inattention blindness" when writing my answer, but missed this because of the ever so slight difference in spelling, although I actually proposed a different word I did provide reference to this term.
    – Quaternion
    Commented Oct 13, 2017 at 22:37
  • I've often seen the term cognitive blindness used as well. Could this answer be updated to indicate whether this is the same thing or something else?
    – MetaEd
    Commented Oct 16, 2017 at 16:39

As a graduate student in computer science (1996), when frustrated from trying to figure out why some code we had written wasn't working, we would often seek help by saying we "needed Captain Obvious" because 99% of the time, a simple, glaring coding error could be spotted by someone else almost immediately.

Crying for help to "Captain Obvious" had the implication that one was suffering from all the terms described in other answers, but further, that the solution sought was a trivial fix and NOT something which required complex thought or deep subject matter comprehension. It was our way of saying we needed help seeing the forest from the trees while priming the helper to not get caught up in the same details which caused our own blindness.

We would NOT ask for "Captain Obvious" if we were having a coding problem where we were unsure of the overall correctness of the code. That kind of help would often require too much time from another (also busy) person.

"Hey, can you look at my code and help me figure out why this won't work?" "No, I'm too busy." (or "Yes" if they weren't, but then knowing it was going to be a mentally challenging and time-draining favor)


"Hey, can you help me with my code, I need Captain Obvious" "Sure." (here there is no expectation to actually help if they didn't see something right away)

"Captain Obvious" was a fixer or problem-solver, not a checker or validator - for the latter, we would simply ask for "many eyeballs".

  • +1 Captain Obvious! a great way to state the issue and politely ask for help, although rather "familiar" to be understood immediately outside those "in the know". Yet I'm an instant fan of the phrase and will be sure to use it in the future, thank you
    – hlecuanda
    Commented Oct 15, 2017 at 4:28

'I couldn’t see it for looking'

'You can't do your own proof-reading'

'It needs a fresh pair of eyes'

'It was right there, in front of my eyes/face!'

'I couldn't see it for love nor money!'

'I needed to sleep on it'


Scotoma(more accurately intellectual scotoma or psycological scotoma):

The term scotoma is also used metaphorically in several fields. The common theme of all the figurative senses is of a gap not in visual function but in the mind's perception, cognition, or world view. Source Wikipedia: https://en.wikipedia.org/wiki/Scotoma#Neuropsychological.2C_psychological.2C_and_intellectual_scotomas

I found this being aware there is a medical term for this (cognitive or physical dysfunction leading to an actual blind spot in the visual field), as well as a mental condition that prevents people from seeing items in a scene or having a figurative blindness to a world view or position that they hold.

However the definition at Wikipedia is still too heavy handed. That is, the connotation is strongly towards a dysfunction not merely of a condition such as being tired, which is what we are trying to convey here. As a software developer I am very aware of the issue you speak of and have heard other developers relate to the issue but they never produced a word for this concept, so thank you for motivating me to search. Hearing of this phenomenon in psychology (unable to see things in front of you) and it being a cognitive dysfunction is where I began the search.

Now what you describe is a cognitive condition albeit a temporary one, experienced by healthy people.

You mentioned this issue being so common that the drafting industry has the process of "red lining" (I'm actually familiar with this process knowing drafters) as well programmers have developed strategies to compensate as well (such as Pair programming or much more typically talking out your issues to a bewildered colleague to externalize the issue[their input is largely irrelevant they are just a sounding board], actually I'm confident that the reason StackOverflow is so popular is because it encourages this externalization which often the mere task of doing so results in solving ones own solution, without bothering anyone).

Interestingly the industry and us healthy people are able to compensate for our issues, it seems that if this issue becomes a serious mental health issue is when people, for whatever reason lose the ability to compensate, this article speaks to this: Dealing with Cognitive Dysfunction

The above article indicates that it isn't so much that people with a dysfunction (it isn't particular to any dysfunction, and does not mention Scotoma specifically) but some inability to compensate which leads to a critical issue. It is said that planes crash typically due to simultaneous failures in multiple systems, so it makes sense that this inability to see things is typical but for it to become a medical concern we need additional failures in compensatory systems for it become a medical issue. As you have noted, people who are from industries where this is common have learned to compensate typically though social means.

This article missing the gorilla in front of your eyes goes over an explanation of the phenomenon it also creates a video which demonstrates the issue in very short order. They have coined the term inattention blindness which I think is a more attractive term (than Scotoma) but it is also a misnomer, as the example isn't due to ones inattention but rather overloading ones capacity to concentrate on multiple things.

Of note, I think that this has something to do with not being able to see your own message. A different viewer is seeing your work without any perceptions and is more critical. However in programming it is sometimes hard to understand someone else's work, for this reason the author themselves is often required to assure the works veracity. Unit tests is one solution (code written from a testing mindset) another is gaining a greater degree of traction over what is a very abstract space by articulating what is to be done, by talking to others (although it isn't what they say but rather the act of verbally reinforcing what needs to be done) a funny thing about this is that we generally need a real person, a stuffed animal or talking out loud isn't typically sufficent enough to move us from our mental space to something more external, we only get that with what we perceive as an actual external entity.

Now the while the act of programming is abstract, it is the process of realizing some process by a computer. There is a clear objective, but one can say that in life people tend to loose focus as well regarding objectives. When tracking certain tasks (like day to day duties) longer strategic objectives are not minded. I found this TED talk Elizabeth Gilbert On Genius to be highly relevant to the idea of gaining external perspective. As an atheist I have to say this is the strongest argument for religion and prayer that I have ever seen, which simply comes down to the concept of an external being being a useful construct to which you can articulate ideas and gain better perspective.

Why I go over this last part is to bring light to the issue that in industries that have standards such as drafting, you can have reasonable external oversight but in a lot of work or in personal matters sometimes you need to find techniques to see your own issues or work clearly as it is unlikely you'll find anyone else that will likely be motivated to proof your work.

Sorry this has been something I have thought about for a while and this post is more a discharge of such thoughts than a simple definition.

  • The gorilla thing has been brought up before: What is it called when something appears so obvious, no one expects it?
    – Mazura
    Commented Oct 13, 2017 at 22:41
  • It's a meme so I'm certain it has appeared often. Anyways it has some context here, can see no reason not to cite it... citations are cheap. Also I'm not really advocating "inattention blindness" but intellectual scotoma, it is mentioned for completeness and while I consider it a nicer sounding expression I feel that scotoma is most articulate to the case, and the only single word which meets the definition.
    – Quaternion
    Commented Oct 13, 2017 at 22:53
  • Inattentional blindness as per the linked article explains one reason for scotoma (more-less attention overload) but I doubt it is not the only reason. The mind filling in blanks and seeing what isn't there is quite different from missing what is there as well as scotoma due to holding an erroneous position and rejecting contrary evidence. All these are very different in nature but have a similar end result to what the OP describes.
    – Quaternion
    Commented Oct 13, 2017 at 23:15
  • Also, "selective attention" or "seeing what you expect to see". Commented Oct 14, 2017 at 5:01


Unmidful, unconsconcious, unaware.


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    Oblivious is more of a permanent condition, this is about a specific acute episode.
    – Kevin
    Commented Oct 11, 2017 at 22:43

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