Medical Problem?

[Damaged]

I know this is off topic but this forum seems to have a very broad mixture of readers so I thought I'd post a personal question (no it doesn't refer to Viagra!)

A few years ago I noticed that when using mobile cranes I had a bit of an issue when looking at the end of the jib, if there was a slight wind it looked like the clouds were staitionary but the end of the jib was moving, I've never really discussed this with anybody because I just assumed that it was normal.

Recently this "problem" has got worse, today I was sat on the foil of a paper machine looking for a defect in a yankee cylinder, the cylinder was rotating at a crawl speed of 3 mtrs / min but I had to keep looking away as 90% of the time the cylinder appeared to have stopped and it felt as though I was orbiting the cylinder...

Question is, does everybody have this issue or do I have a problem?

 

[fingers99]

It does sound as though it might be a problem with difficulty in focussing. Might be worth paying a visit to an optician. Thing is, eyesight changes (almost always for the worse) almost imperceptibly with age.

Of course, I could be completely wrong, but it's where I'd start -- what are eye tests? £10 at ASDA?

 

[Paul.]

I do quite a bit of work on wire belt conveyors, sometimes when you look at them your eyes cant decide whether to focus on the bed, or the return run of belt below it, even worse when they're running because they go in different directions, Perforated sheet can have the same effect, you don't know whether to look at it or through it, I think its because I'm far sighted, as its ok when wearing glasses,

 

[Archie]

OK. So if I understand correctly, this is like when you're sitting on a train and reading a book. Out of the corner of your eye you see movement and you think the train has started off.

If this is the case then isn't this just the theory of relativity? Without an outside frame of reference it's impossible to tell what is moving. It's only when you look up that you realise it's the train next to you that is moving, not yours. You realise this because when you look up, you also see the platform which you know to be stationary. This is your reference frame. If you see yourself to be stationary relative to the platform then you know that it is the other train that is moving. However, without this reference frame, you can't tell who is moving and who is not.

To be perfectly honest I hated this part of physics when I was at school so I'm in no way qualified to talk about it but I remember enough that I think this is what's going on. IMHO, you've got nowt to be worrying about!

Now if that doesn't get you scratching your head....

 

[Welderpaul]

I think it's just a perception of things.
Many times i've been up in a cherry picker, the basket of the machine is swaying in the wind, but your mind thinks it's the building moving.
Big pairs of gates hanging up for spraying - when your on an ally tower and the gate is swinging, it seems like the tower is moving.
Either it's normal or we're both a bit odd?!

 

[jugs]

Hi mick

Yes you have a problem, so take Viagra!

Sorry, I’ll try to be serious.

“Question is, does everybody have this issue or do I have a problem”

Yes we do & I doubt it.

The eye see’s the world in 2 ways-
1. Sharp focus, detail seen through centre of eye,
2. Movement, seen through the side or peripheral vision

The brain process’s all this info @ the same time so can be tricked.
All you are seeing is an optical illusion, the same as if you stare at certain patterns they appear to move, or if you look @ a TV screen with white dots moving from the centre to the edges you think you are speeding thro space as the stars appear to ‘come towards you’. When you’ve driven @ night go straight to bed, close your eyes & can still see headlights coming towards you.

“Recently this "problem" has got worse, today I was sat on the foil of a paper machine looking for a defect in a yankee cylinder, the cylinder was rotating at a crawl speed of 3 mtrs / min but I had to keep looking away as 90% of the time the cylinder appeared to have stopped and it felt as though I was orbiting the cylinder...”

Because you were focused on the cyl, and I bet there was mains powered light giving you a harmonic distortion as well. (if it’s a problem, turn off mains lights & use a battery powered spot lamp @ a low angle)

You only need to worry if this is your ‘normal ‘ vision.

Hope this is of use

 

[Paul.]

See what your eyes make of this then.

 

[jugs]

Hey paul

I've been looking for those, where did you find them.

 

[Paul.]

A mate sent me it by e mail, ill ask him, heres a few to be going on with.


Edit: He says its here but I cant see it, theres some similar ones though.

 

[scarecrow]

the ones on the outside aren't working. send it back

 

[Hitch]

I know what you mean with the crane jib, can be quite disoriating.
The mesh thing, thats horrible.

Cherry pickers and towers, not really noticed problems with them myself.

 

[Drains]

Ever get the one where you're sitting in traffic on a hill and you start sliding backwards, so it's a mad panic as you foot the brake - which doesn't work, then wrench the handbrake off it's hinges, which also doesn't work, then the car next to you drives away, and you stop moving...

And then you can't move, cos some silly sod's gone and ratcheted the handbrake so tight you need a crowbar to get it off.

 

[madkayaker]

I was on a 1000ft telecoms mast and the tower way swaying a little bit but the wind 900ft higher up was moving the cloud a lot faster and i felt i was dong 100mph! Very strange when it happens.

 

[Damaged]

Thanks Gents

I've had my eyes tested and still have 20/20 vision so will put it down to a natural thingimy.

Sorry for the question but I hate going to the quacks.

 

[andypocock]

Sorry for the question but I hate going to the quacks.

Who needs a doctor? Just ask a bloke with a welder