How many nits can we perceive with human eyes and are cameras keeping up?

[FranceBB]

Hi there,
brand new topic for those like me who are always interested in those things.
So the question is pretty simple, really: how many nits can the human eye see and how far off are we from getting there?

Well, I've been asked this question a lot whenever I explain HDR to new people and so far I haven't been able to give a precise answer, but I'll try to sum up what I know ;)

Now, we know that the highest possible value for PQ as a color curve is 10'000 nits, however we were more like "optimistic" pushing the limit as high as we could for future generations more than anything 'cause back when PQ was introduced, there was no camera able to record with as many stops / nits and afaik there still isn't. If we take a look at consumer cameras like the Sony A7 III we see as little as 690 nits, while if we take a look at professional cameras like the Red Monstro 8K, we see as many as 17 stops, so with a little calculation (1153:10.2 = x:17) we get 1921.6 nits.

So it's pretty much clear that even the best and brightest camera sensors are still not good enough to give us a result that tops the maximum available limit set by PQ (or by other logarithmic curves for that matters), so it's pretty clear that when we see movies shot in log and mastered at, let's say, 5000 nits, it means that it's almost definitely thanks to CGI and other kind of effects that we get something that high (after all they're computer generated, so we can get them as high as we want).

Anyway, we're digressing, back to the topic: how many nits / stops can we see?

Well, we know that direct sunlight is 1,600,000,000 nits, however we also know that there's NO WAY we can see it without burning our eyes and getting a permanent damage.
What about something we can actually see and that's in the spectrum of visible light without damaging our eyes?

Well, here is a chart for you:

https://qph.fs.quoracdn.net/main-qimg-45903a545b5995ddc401159385379ff8.webp

During a sunny day at the beach with little to no clouds we're comfortable seeing around 100,000 nits in the sand, while reflected light on other objects can be much less, like for instance this flower has a peak of 14,700 nits of reflected sunlight:

http://www.son-video.com/images/illustration/guides/tout-savoir-sur-HDR-Dolby-Vision/Dolby-Vision-Fleurs-Nits.jpg

Fine, but what about what we can see before burning our eyes? Well, if you were to look straight at a light source with your own eyes (even if it's not as bright as the sun), you will start to have permanent damage around 250,000 nits.

So... the future is definitely interesting and I look forward to be able to see how far we'll be able to go with the camera sensors, 'cause our eyes are still easily outperforming the best technologies out there, but... will it be like this in 20, 30, 40 years? Who knows...

What do you think? Have your say below. :)

[wswartzendruber]

Let's say that PQEOTF(1.0) produces a value of 10,000 nits. PQEOTF(1.5) then produces a value of 3,140,795 nits. So it seems like applying 12-bit encoding could be a simple hack to go above 10,000 nits, but with 12 bits, the values get explosively high.

[Katie Boundary]

I've looked directly at the sun without suffering permanent damage. WTF are you talking about?

[FranceBB]

I've looked directly at the sun without suffering permanent damage. WTF are you talking about?

"without glasses and for an extended period of time" is the important bit eheheheheh

From the NHS website (a reliable source):

When you stare directly at the sun ultraviolet light floods your retina, damaging the exposed tissue. Short-term damage includes sunburn of the cornea (known as solar keratitis). This results in light sensitivity and pain, with symptoms generally showing up within 24 hours of exposure. More serious damage is known as solar retinopathy and it occurs when UV light burns the retinal tissues. It destroys the rods and cones of the retina and can create a small blind spot in the central vision, known as a scotoma. The retina does not have any pain-receptors, so you won’t feel the damage being done.


Long term damage:

Most people who experience solar keratitis and solar retinopathy make a full recovery, however, depending on the level of damage, this can take up to 12 months. Others never fully recover complete vision, and continue to experience vision problems such as blurriness or spots.

[nevcairiel]

Your brain won't let you look at the sun directly under normal circumstances, unless you really force it. Its only a risk if you like look at a solar eclipse without protection and the sun re-appears and your safeguards don't catch on quickly enough.

[kolak]

Look at Dolby documents. They done quite a bit of study around it. 10bit is not enough to work with HDR footage:

https://exse.eyewated.com/fls/1f0544c14cbf2015.pdf

[kolak]

I been also told by Dolby guy that human eye can see about 20 stops, but human eye is adaptive, so this is dynamic range.
When you go out from dark to bright then it needs time to adapt (at first bright hurts but after short time it doesn't). Same if you go to dark- first pitch black and later you start seeing shadows. It's rather complex subject.

[StainlessS]

If you get a 'flash' of UV from a welders arc, you probably won't feel much at the time, but later that night
may feel like you got hot sand in your eyes, and maybe headaches.
[I think is said that indirect flash rather than directly looking at flash can be bigger hazzard]

UV from heavy duty mercury arc rectifiers can have same effect.
Like a firework display in a 4 or 5 foot tall bottle, used where big DC cranes are in use, or maybe eg tube train DC power source,
a bank of 5 or 6 of these bottles all flashing can be very impressive. [usually enclosed in a steel cabinet for safety]
EDIT: There are a few clips of Mercury Arc Rectifiers on YouTube, alas, clips I viewed were a bit pathetic as a firework display,
need to see in working shipyard or similar with hundreds of cranes, welders, and metal cutting machines in constant on/off operation.

[Katie Boundary]

ultraviolet light floods your retina, damaging the exposed tissue

That's... at least partially incorrect. The lens in the human eye contains a special kind of opsin that is transparent to visible light but opaque to ultraviolet light. This is the real reason why humans can't see UV light - it has nothing to do with what our cones can or cannot detect. The blue cones in our eyes are actually quite sensitive to UV light. If the lens is surgically removed, we gain the ability to see into the UV spectrum. I know this firsthand because I had the lens in one of my eyes removed and now I can see UV light in that eye.

[hello_hello]

I know this firsthand because I had the lens in one of my eyes removed and now I can see UV light in that eye.

Did you look directly at the sun for too long and damage it?

[Balling]

Most Tertachromates (people with mutation that gives you 4 different types of cones) can see in UV at least when they are younger. Some Tetrachromates just see more colours in the whole spectre. So the fact about opsin is also only half correct.

[Balling]

When you go out from dark to bright then it needs time to adapt (at first bright hurts but after short time it doesn't). Same if you go to dark- first pitch black and later you start seeing shadows. It's rather complex subject.

If it hurts, you have poor eye health. Alas, most of us do.

[Balling]

Your brain won't let you look at the sun directly under normal circumstances, unless you really force it. Its only a risk if you like look at a solar eclipse without protection and the sun re-appears and your safeguards don't catch on quickly enough.

That is CNN fake news, as you americans say, as you can see time of corrections on this article. https://en.wikipedia.org/wiki/Photic_retinopathy. We have special protections that turn our cones off for a couple of minutes when they are exposed to direct sunlight. So it is not dengerous. Also, what can be dangerous is a lot of UV light from direct exposure, but most people watch it in house, but any glass does not passthrough UV light. Both A type or B UV light (the first one causes cancer and actual tan and second one is used to produce Harmone D3 and get more so called unpigmented melanin that UV A then activates). And what is most important it is only dangerous to people with bad eye health, they cannot be out even in 30 °C weather, like myself and cannot open their eyes even not looking onto sun.

What is totally dangerous is this: https://youtu.be/DMVWW-bmKwQ

I have that 1.3 W laser. Even just side glancing (no direct exposure, of course) on laser beam of 1.3 W will cause you the same effect sun will, i.e. cones will turn off. Even glasses do not protect much.

[Balling]

Look at Dolby documents. They done quite a bit of study around it. 10bit is not enough to work with HDR footage:

https://exse.eyewated.com/fls/1f0544c14cbf2015.pdf

That's not that simple 12 bits are only needed to preserve all 10000 nits. Because for between 5000 and 10000 nits only 7% of 10 bit codepoints are used. See SMPTE-2014-05-06-EOTF-Miller-1-2-handout_389998_1.pdf

While most use 1000 or 4000 max.

[videoh]

any glass does not passthrough UV light. Both A type or B UV light False. About 75% of UVA passes through ordinary glass.

[Balling]

False. About 75% of UVA passes through ordinary glass.

Nobody uses ordinary glass for windows though. Just like for glasses for that matter, specific stuff with better 1.74, 1.67 coeff. are used with dual aspherics. A source on that?

[hello_hello]

All I know is if I look directly at the sun it's incredibly uncomfortable and within a short time painful. Well, I wouldn't describe it as "normal" pain but my brain definitely wants me to feel quite uncomfortable until I stop doing it.

Optical Transmission - Soda Lime Glass ("ordinary" glass)

https://web.archive.org/web/20120327213950im_/http://www.sinclairmfg.com/images/curve_sl.jpg

https://web.archive.org/web/20120327213950/http://www.sinclairmfg.com/datasheets/optical3.html

According to the info here (https://www.theguardian.com/science/2002/may/30/medicalscience.research), all three color receptors in our eyes are similarly sensitive to UV, but if you've had a lens amputated you probably don't see UV light as such. Apparently our brains aren't wired for it.

The eye represents a compromise between clear focus and breadth of spectrum. What does ultraviolet look like? Prof Stark possesses UV vision because he is aphakic in one eye and, with Professor Karel Tan, has published research on the nearest visible equivalent. His conclusion is that it looks whitish blue or, for some wavelengths, a whitish violet.
This appears to be because the three types of colour receptor (red, green and blue) have similar sensitivity to ultraviolet, so it comes out as a mixture of all three - basically white, but slightly blue because the blue sensors are somewhat better at picking up UV. Our sensory system does not appear to be geared to revealing additional colours beyond the violet, though other animals will see things differently.

As a side note, am I the only person who had no idea humans have a literal blind spot? I always assumed "blind spot" referred to something outside of peripheral vision. I tried the blind spot test here though, and it freaked me out. How clever is the human brain, interpolating the missing info so flawlessly.
https://en.wikipedia.org/wiki/Blind_spot_(vision)

[StainlessS]

Some time about the 60's I think, a baby was born with an eye infection.
Doctor prescribed an eye patch for 1st 3 months after birth.
Afterwards, baby was totally blind in that eye, brain is in process of 're-wiring', where brain cells not passing messages will commit suicide.
[massive brain cell death during first few months after birth, getting rid of cells without function].
Doctors will now never prescribe eye patch in those circumstances.

Sometimes, where brain cells not 'in-use', can be re-functioned for other purpose. Some people have sensory paths which are sorta cross-wired,
visual processing may pick up signals from ears, nose or tongue, in which case those people may claim eg chocolate tastes Blue,
or Chopin/Mozart smells sour, where senses are a bit mixed up. The people that it concerns (about 1 in a million) are quite often unaware that they are unusual
and think everybody is similarly 'gifted'. Where this phenomenon occurs, people with the same 'cross-wired' senses, will describe the exact same
results, eg chocolate tastes blue, or whatever. Very strange, dont remember what its called.

EDIT: This looks like it: Synaesthesia
https://www.theguardian.com/science/2010/nov/19/synaesthesia-cross-overs-senses

Synaesthesia - crossovers in the senses
Nabokov experienced colour with each sound, Kandinsky heard music with a splash of paint, both had synaesthesia, a rare neurological condition which causes the senses to intertwine
The Nobel Prize winning physicist Richard Feynman reported seeing equations in colour. The artist Wassily Kandinsky tried to re-create the visual equivalent of a symphony in each of his paintings. And Vladimir Nabokov wrote, "One hears a sound but recollects a hue, invisible the hands that touch your heartstrings. / Not music the reverberations within; they are of light. / Sounds that are colored, and enigmatic sonnet addressed to you."

All had synaesthesia, a harmless neurological condition in which activity in one sensory modality, such as vision or hearing, evokes automatic and involuntary perceptual experiences in another, due to increased cross-talk between the sensory pathways in the brain.

EDIT: And apparently is now known to be a lot more common
Once thought to be extremely rare, synaesthesia is now believed to affect between 1 and 4% of the population.

Wikipedia:- https://en.wikipedia.org/wiki/Synesthesia

Youtube:
https://www.youtube.com/watch?v=BwhBvNpKKUo
https://www.youtube.com/watch?v=FDLKWDSx4g0
https://www.youtube.com/watch?v=vEqmNX8uKlA
https://www.youtube.com/watch?v=eHH7CxYVkAo

[wonkey_monkey]

As a side note, am I the only person who had no idea humans have a literal blind spot? I always assumed "blind spot" referred to something outside of peripheral vision. I tried the blind spot test here though, and it freaked me out. How clever is the human brain, interpolating the missing info so flawlessly.


I've got a heater with simulated flames - just bits of ribbon blown about and lit by an orange light - and if I look in a certain direction it seems to freeze. As soon as I look directly at it, it unfreezes.

[kolak]

That's not that simple 12 bits are only needed to preserve all 10000 nits. Because for between 5000 and 10000 nits only 7% of 10 bit codepoints are used. See SMPTE-2014-05-06-EOTF-Miller-1-2-handout_389998_1.pdf

While most use 1000 or 4000 max.

Yes, but we are talking about full eye potential which doesn't end on eg. 4K nits.

[kolak]

If it hurts, you have poor eye health. Alas, most of us do.

It doesn't hurt.
Eye just needs time to adapt and change its 'sensitivity'.
Point is that eye has quite good range, but it's not covered at one time.
Is this what we are trying to mimic with dual ISO sensors?
Who said sensor needs to have 20 stops of dynamic range. They can have 10 static, but be able to shift them into different regions. I assume problem is with this 'shifting'. As always- we are faaaar from nature.

[rwill]

As a side note, am I the only person who had no idea humans have a literal blind spot? I always assumed "blind spot" referred to something outside of peripheral vision. I tried the blind spot test here though, and it freaked me out. How clever is the human brain, interpolating the missing info so flawlessly.
https://en.wikipedia.org/wiki/Blind_spot_(vision)

Funny Test: Move an icon on your desktop to the center of the desktop. Look at it directly with one eye and close the other eye. Move the mouse cursor around, it should become more bumpy further away from the center. Bonus points if you start to move colored things around on your desktop and notice the color perception becoming lesser the more you are off the center. I would not do this for longer than 1 minute or so, it screws with the brain.

The ability of the human brain to interpolate or mitigate missing vision details is one of the reasons why certain more or less slowly developing eye conditions like AMD or Glaucoma are most of the time not perceived in their early stages by patients.

Regarding additional or missing cones for color perception, I remember reading that quite a number of people are color blind but have not realized that. There was some Boss in World of Warcraft ( some mechanical gnome or something ) that required the ability to differentiate RGB colors and well... thats the encounter where some people realized they had a slight disability.


Oh, and all hail the Mantis Shrimp.

[FranceBB]

I've got a heater with simulated flames - just bits of ribbon blown about and lit by an orange light - and if I look in a certain direction it seems to freeze. As soon as I look directly at it, it unfreezes.

Yeah I've experienced it too.
It's pretty weird but it makes sense once you realize how the brain works to cover for the missing bits that the eye can't see.


Point is that eye has quite good range, but it's not covered at one time.
Is this what we are trying to mimic with dual ISO sensors?


Yep, I think we're going in this direction to be fair.


As always- we are faaaar from nature.

Sadly yeah... :(

[hello_hello]

Some time about the 60's I think, a baby was born with an eye infection.
Doctor prescribed an eye patch for 1st 3 months after birth.
Afterwards, baby was totally blind in that eye, brain is in process of 're-wiring', where brain cells not passing messages will commit suicide.
[massive brain cell death during first few months after birth, getting rid of cells without function].
Doctors will now never prescribe eye patch in those circumstances.

I'd have thought the brain would catch up after only three months, but apparently not.

I read somewhere that the brain mainly uses one eye for seeing and the other one is mainly used to add effects (3D).
Apparently we're right or left eyed, just like we're right or left handed. I'm left eyed and right handed. Before I discovered that, I never understood why using my right eye to look through a camera viewfinder (remember those?) felt less comfortable than my left one, and also ran a higher risk of producing a badly framed shot. If anyone cares, there's some tests here for checking which eye your brain is doing it's seeing with. https://en.wikipedia.org/wiki/Ocular_dominance#Determination

I watched a few documentaries on the brain recently. One included a story on a woman who lost the use of one eye at an early age. 30 years later she had an operation to restore the sight in that eye. It was a success but her brain had no understanding of depth perception. A specialist gave her exercises to see if she could train her brain to process 3D, but told her not to get her hopes up. She did them religiously for 6 months without any change, so she was ready to give up when one day she got into her car, put the key in the ignition, and her brain picked that moment to process the steering wheel in 3D so it jumped out at her and gave her a fright.

My favourite documentary was the one about removing half the brain to stop seizures when all else fails. Apparently sometimes the two sides of a brain can't agree on who's driving.
The 12 year old who had half his brain removed lost the use of one side of his body at first, but the remaining half built new neural pathways at the speed a 12yo old brain can build them, and 6 months later he was virtually normal again.
The 76yo old woman... her brain wasn't keen to come out of retirement, and she lost the side with the speech centre too. I shouldn't call it funny, but it was a bit funny. Her remaining brain had no idea the speech centre was gone so it kept processing speech oblivious to the fact it wasn't processing words but complete gibberish instead, and she'd get frustrated when no-one could understand her, because as far as she was concerned she was speaking normally.

[FranceBB]

The 76yo old woman... her brain wasn't keen to come out of retirement, and she lost the side with the speech centre too. I shouldn't call it funny, but it was a bit funny. Her remaining brain had no idea the speech centre was gone so it kept processing speech oblivious to the fact it wasn't processing words but complete gibberish instead, and she'd get frustrated when no-one could understand her, because as far as she was concerned she was speaking normally.

I saw this when I watched 24 hours in A&E on Channel 4. Sometimes, when people had a blood cloth and were rushed to the hospital, they lose the ability to speak. They think they're speaking normally but they are not and what they say is just a weird combination of sounds, thus making it impossible for everyone to understand. Most of them are then saved by a cloth busting agent followed by an operation and then they recover. In the interviews they have afterwards they show them the videos and they look shocked as they hear what they were really saying. In those interviews, they always say that they thought they were speaking normally.

[Balling]

As a side note, am I the only person who had no idea humans have a literal blind spot? I always assumed "blind spot" referred to something outside of peripheral vision. I tried the blind spot test here though, and it freaked me out. How clever is the human brain, interpolating the missing info so flawlessly.
https://en.wikipedia.org/wiki/Blind_spot_(vision)

That is nothing! Did you know our eyes can do clockwise and counter clockwise movement but we cannot control it? https://youtu.be/DkaJ6iK2CJc

[Balling]

Yes, but we are talking about full eye potential which doesn't end on eg. 4K nits.

It does not end on 1.6 billion nits of the sun either...

[Balling]

I'd have thought the brain would catch up after only three months, but apparently not.

I read somewhere that the brain mainly uses one eye for seeing and the other one is mainly used to add effects (3D).
Apparently we're right or left eyed, just like we're right or left handed. I'm left eyed and right handed.



This is literally taught at school, that if you are right handed left eye is the active one, if you are left handed right eye is active. Obviously, not active eye usually gets evolutionally worse miopia and astigmatism, WHICH ARE PURELY genetic BTW.

I do not understand how do you think our brain is supposed to work? We cannot see both pictures from both eyes because they are different, just like 3D Blu-rays' pictures are different. And no, the second eye is also used to do a better picture unless it has insane miopia.

[hello_hello]

This is literally taught at school, that if you are right handed left eye is the active one, if you are left handed right eye is active. Obviously, not active eye usually gets evolutionally worse miopia and astigmatism, WHICH ARE PURELY genetic BTW.

You probably should let wikipedia know they've got everything wrong.
https://en.wikipedia.org/wiki/Ocular_dominance#Determination

Ocular dominance, sometimes called eye preference or eyedness, is the tendency to prefer visual input from one eye to the other. It is somewhat analogous to the laterality of right- or left-handedness; however, the side of the dominant eye and the dominant hand do not always match.

Approximately 69.42% of the population are right-eye dominant and 29% left-eye dominant.

In those with anisometropic myopia (different amounts of nearsightedness between the two eyes), the dominant eye has typically been found to be the one with more myopia.

I do not understand how do you think our brain is supposed to work? We cannot see both pictures from both eyes because they are different, just like 3D Blu-rays' pictures are different. And no, the second eye is also used to do a better picture unless it has insane miopia.

So you're saying we can't see both pictures from both eyes because they're different, just like 3D video has two different pictures, which our brain combines into a single 3D image... and the second eye also contributes to a better image even though it can't, or something...

Of course you can see pictures from both eyes. Hold a finger a couple of inches from your nose and look past it to your monitor. At the right distance your finger will look fairly transparent and you'll be able to see the whole monitor, so I assume when something's too close or the pictures are too different for your brain to sort out the parallax and combine them, it applies an overlay filter instead.

I'm glad I'm not a bird with eyes pointing in opposite directions. I'm sure a bird's brain knows how to make sense of two completely different images even if the human brain couldn't.

[FranceBB]

I'm glad I'm not a bird with eyes pointing in opposite directions. I'm sure a bird's brain knows how to make sense of two completely different images even if the human brain couldn't.

Yeah but they have to move the head in that specific way. If you look at the ridiculous way pigeon move, that's actually for their brain so that they can create a mapping of the whole area. I'm far too ignorant in this regard, but several years ago one of my mother's university professor published a whole study about how pigeons see and how their brain interprets things. I've never read it, though.

[Asmodian]

I'm far too ignorant in this regard, but several years ago one of my mother's university professor published a whole study about how pigeons see and how their brain interprets things. I've never read it, though.

It is a very interesting topic. Brains are super weird, the difference between the input data and what we experience as "seeing" is shocking.

Pigeons on treadmills are awesome too.

[hello_hello]

Yeah but they have to move the head in that specific way. If you look at the ridiculous way pigeon move, that's actually for their brain so that they can create a mapping of the whole area. I'm far too ignorant in this regard, but several years ago one of my mother's university professor published a whole study about how pigeons see and how their brain interprets things. I've never read it, though.

Is it only pigeons or is it all birds?
Horses have a similar setup, do they......
Never mind. I asked Wikipedia.
https://en.wikipedia.org/wiki/Equine_vision#Visual_capacity_of_the_horse

[StainlessS]

Yes, prey animals tend to have eyes on side of head, hunters facing forwards.

[FranceBB]

prey animals tend to have eyes on side of head, hunters facing forwards.

For some reason (probably 'cause you're British) I read your comment with the David Attenborough's voice eheheheheh

[StainlessS]

Yes, I speak exactly like him. [you probably could not tell the difference]
:)

[hello_hello]

I was reading about color perception a few days ago, which eventually led me to reading info on the Cornsweet effect, something I'd not heard of. I know our brains are adaptive and perception is influenced by many things, and looking at most illustrations demonstrating color perception I can understand why I might see non-existent differences, but enough is enough. This is where I'm drawing the line. The two objects in this picture are not the same color. I don't care my color picker says otherwise. It must be broken.

The edges where they meet aren't the same, but their main surfaces are identical according to my broken color picker.

Click for the full size version.

https://i.postimg.cc/Hc35MQ61/Picture-E.png (https://postimg.cc/Hc35MQ61)

Why We See What We Do (pdf). (https://www.americanscientist.org/sites/americanscientist.org/files/20051220143043_306.pdf)

[Balling]

In those with anisometropic myopia (different amounts of nearsightedness between the two eyes), the dominant eye has typically been found to be the one with more myopia.





Oh, wow. Okay. I should check my school books then. :) Also, it looks like I have same hand eye side too (both right), which indeed does have worse miopia.

[j7n]

If no practical cameras offer sufficient dynamic range, how was the picture of the flower taken?

After walking out of a sunlit area, I can't see anything for a few minutes. Even bright objects or text on a normal monitor prevent me from seeing darker areas or banding there. Movies on a normal monitor look fine to me. And if it is set to low contrast, I can still see the table, food and drink. I'm near sighted, and probably with imperfect lens which causes the most disliked "bloom" effect. Would it be "safer" to look at the sun with near sighted eyes because they don't focus the light source accurately?

[FranceBB]

If no practical cameras offer sufficient dynamic range, how was the picture of the flower taken?

They combined different takes. When I said the number of nits a camera can have, the conversion was being done by the taking the stops of the sensor and fixing the black at 1.x, however stops are like brackets, so you can move them, therefore if you take different pictures repeatedly by moving those brackets you can get a much higher dynamic range. This is the reason why cameras have many more nits in pictures than they have in videos.

[Balling]

Oh, wow. Okay. I should check my school books then. :) Also, it looks like I have same hand eye side too (both right), which indeed does have worse miopia.

I read some books on miopia and astigmatism, apparently if you are not correcting vision, the better eye is always the main one. Only after glasses or contact lenses the main eye will change to the one of your leading hand.

[FranceBB]

I read some books on miopia and astigmatism, apparently if you are not correcting vision, the better eye is always the main one. Only after glasses or contact lenses the main eye will change to the one of your leading hand.

I see. Interesting.
I really hope the day I'll have to wear glasses will never come. I don't really like the feeling and the fact that you gotta carry them around every flipping time.
On the other hand, contact lenses are not good either, 'cause they're a pain to put on and then remove, especially if you leave them on for more days than expected (according to what my shortsighted friends say), so... either way, it's not something I'd like to do.