Kobo forma screen flickering/pwm issues

[JSWolf]

So from what's being said, the Forma doesn't cause any noticeable flickering and those complaining about flickering are just doing so based on the idea of PVM and/or having watched a video.

[Tokei]

Originally Posted by JSWolf

So from what's being said, the Forma doesn't cause any noticeable flickering and those complaining about flickering are just doing so based on the idea of PVM and/or having watched a video.

With all due respect but I think your are construing a conclusion here. I think the poll says it all: 8 were bothered by PWM, 50 not. So most are fine, but I would not dismiss the 8 even though clearly in the minority and assume they are imagining things or trolling based on a video they saw. The studies that have been discussed in this thread showed that people can have adverse effects even with higher refresh rates than the ones used by the Forma. Rare, yes. But nonexistant, no.

[meeera]

Originally Posted by Tokei

With all due respect but I think your are construing a conclusion here. I think the poll says it all: 8 were bothered by PWM, 50 not. So most are fine, but I would not dismiss the 8 even though clearly in the minority and assume they are imagining things or trolling based on a video they saw. The studies that have been discussed in this thread showed that people can have adverse effects even with higher refresh rates than the ones used by the Forma. Rare, yes. But nonexistant, no.

I've not seen any convincing evidence of that at all. And there is no real plausible physiological mechanism proposed to date.

The data in this poll is of about the same use as the data saying that a certain percentage of people developed x side effect while they were on y drug. Without a controlled randomised blinded trial and a good placebo, and replication, it means nothing about causation.

I am not saying that people are deliberately trolling; however, if they have experienced 'eyestrain' symptoms, I do not know on what basis they are attributing them to PWM. There are multiple other far more likely mechanisms.

[Tokei]

I think there are studies that confirmed a negative effect of flickering. There is also a physiological explanation. However, the question what flicker rate is safe is not so clear.

Quoting from a link I have shared much earlier in this thread: “[...] flicker is no longer perceived consciously but it can nevertheless have effects on our neurological system. This is because the optic nerve and the cortex can detect stimuli up to 160 Hz, depending on modulation and wave form. In the retina itself stimuli up to 200 Hz have been identified in tests.”

Even with a higher frequency, when interfering with other light sources or optical stimuli, negative effects have been found in studies. Another quote from the same link: “It is strongly recommended that LEDs should be operated above 3 kHz because at this frequency no evidence has been found of any effects on humans.”

I didn’t have the impression that these kind of studies are paid-for bogus studies either (the link quoted is based on an industry recommendation from the IEEE)

[meeera]

Originally Posted by Tokei

Quoting from a link I have shared much earlier in this thread: “[...] flicker is no longer perceived consciously but it can nevertheless have effects on our neurological system. This is because the optic nerve and the cortex can detect stimuli up to 160 Hz, depending on modulation and wave form. In the retina itself stimuli up to 200 Hz have been identified in tests.”

The Forma is 1000 Hz. What you have said does not support your previous assertion of "The studies that have been discussed in this thread showed that people can have adverse effects even with higher refresh rates than the ones used by the Forma."

[JSWolf]

Originally Posted by Tokei

With all due respect but I think your are construing a conclusion here. I think the poll says it all: 8 were bothered by PWM, 50 not. So most are fine, but I would not dismiss the 8 even though clearly in the minority and assume they are imagining things or trolling based on a video they saw. The studies that have been discussed in this thread showed that people can have adverse effects even with higher refresh rates than the ones used by the Forma. Rare, yes. But nonexistant, no.

The thing is, we don't know who it is that voted yes. So we cannot question them. It could be because of reading about PVM or seeing a video that they think it's flickering. I think it's a placebo effect.

Davifor's post is the most convincing of all that there is no perceivable flicker. Someone that sensitive would be having some sort of problem if the flickering was a bother.

[Tokei]

Originally Posted by meeera

The Forma is 1000 Hz. What you have said does not support your previous assertion of "The studies that have been discussed in this thread showed that people can have adverse effects even with higher refresh rates than the ones used by the Forma."

The IEEE recommendation discussed in the link that I quoted earlier is based on a meta-study. Several studies found negative effects also above 1kzh, which explains the second quote I used that recommends a frequency above 3khz.

The same meta study is also used in a presentation from the US Department of Energy you can find here:
https://www.energy.gov/sites/prod/fi...htfair2015.pdf

On slide 18 you can see the recommended frequency based on the modulation. The curve was plotted along the various studies looked at with a dot representing a study result. There are studies that found effects well beyond 1Khz.

Anyway, this is just retreading a prior discussion, so I leave it at that.

[MGlitch]

As I said back when this was a new topic

This poll is laughable since it presumes causation in its answer. There are tons of reasons someone could have eyestrain while reading. Reasons which have nothing to do with flickering. The current results, which are close to the results from back then, indicate that a small fraction of respondents even had any issues with eyestrain, but doesn't talk about how big an issue it was.

[JSWolf]

You could even have eyestrain just using the front light which again has nothing to do with PVM/flicker. You could have eyestrain from being tired. Maybe you are in the beginnings of a cold or other illness. There are a number of reasons that have nothing to do with PVM/flicker.

So the thing is, unless you know for sure it's the device causing the eyestrain, then you cannot say that the PVM/flicker is a problem.

[koboyedi]

Wow, this discussion is drifting towards flat-earther territory, so this has to be said:

It's classical physics guys! There is not a shred of doubt PWM has an effect on people and yes (!), you don't get to have an opinion on that, since it's not up for debate. The only question is to what extent people are affected.

Next to this, most people who experience issues are not even aware their problems could be caused by something they don't visibly notice, hence the true number of affected readers is 'very likely' much higher than any forum poll could suggest.

To sum it up, there is no question if there is a problem, only how serious it is.

[JSWolf]

Originally Posted by koboyedi

Wow, this discussion is drifting towards flat-earther territory, so this has to be said:

It's classical physics guys! There is not a shred of doubt PWM has an effect on people and yes (!), you don't get to have an opinion on that, since it's not up for debate. The only question is to what extent people are affected.

Next to this, most people who experience issues are not even aware their problems could be caused by something they don't visibly notice, hence the true number of affected readers is 'very likely' much higher than any forum poll could suggest.

To sum it up, there is no question if there is a problem, only how serious it is.

And it could be that you are making more of it then it really is. It could be there are less people affected then you think.

[MGlitch]

Originally Posted by koboyedi

Wow, this discussion is drifting towards flat-earther territory, so this has to be said:

It's classical physics guys! There is not a shred of doubt PWM has an effect on people and yes (!), you don't get to have an opinion on that, since it's not up for debate. The only question is to what extent people are affected.

Next to this, most people who experience issues are not even aware their problems could be caused by something they don't visibly notice, hence the true number of affected readers is 'very likely' much higher than any forum poll could suggest.

To sum it up, there is no question if there is a problem, only how serious it is.

Really the only conspiracy theory spewing is from the PWM caused this issue.

Literally no one has said PWM can’t cause issues, especially when it’s improperly implemented. Only that in the Formas case it has been properly implemented. And that there are other causes for eye strain which are more common and more likely than PWM.

But please do ignore illness, weakening eyes, lighting outside of PWM, stress, etc etc. it’s obvious that all 15 people who’ve responded in the affirmative had none of those issues because they pressed a button on a poll.

I guess we can chuck scientific testing out and just have 65 people fill out a binary poll with absolutely no control or regulation over the sample experience.

[koboyedi]

Originally Posted by JSWolf

And it could be that you are making more of it then it really is. It could be there are less people affected then you think.

Yes, absolutely! As you suggested it might be only a small percentage of readers that are affected. I just think it's important to point out that this issue is not imaginary and acknowledge those people who voted that they are affected.

Kudos to everyone who doesn't have a problem. I think there's no real alternative to the Forma if you fancy this screen size. I do fancy it a lot.

[MGlitch]

Originally Posted by koboyedi

I just think it's important to point out that this issue is not imaginary and acknowledge those people who voted that they are affected.

Except there’s not enough evidence that those 9 people are having issues because of PWM.

No one doubts they have eye strain while reading. But you can’t tell people “this is causing your eye strain” and then ask them if they have eye strain because of that as a foundation for any claim.

[JSWolf]

If you replied yes in the poll, please explain what it is you are seeing or what is happening. Please be as specific as possible. Thanks.