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Laser Stimulating Eyes to Focus More Effectively?

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Hi Guys,

Long time lurker and first time poster, sorry if this should be in another section. :)

I have noticed with higher brightness lasers such has my "1mW" ;) ebay 532, and my 1W 445 home build (thanks DTR) that after pointing them and viewing the dot around the backyard (distance of 10 - 20 metres) that my vision seems slightly improved.

I am very short sighted, and can only focus around half a metre in front of my face without glasses before things go out of focus and I am going to be due for a new prescription in the coming months. After using the lasers however I find that for a short time afterward my long distance vison with glasses is a little crisper.

I'm thinking one of two things:

1: The bright light is stimulating the muscles/focal mechanisms in my eyes causing them to move faster/ further than normal. (Obviously no expert on this)

2: I'm being hyper aware of my eyesight after using lasers and it's me subconsciously trying to make sure there are no flaws or damage.

Does anyone who has any knowledge on this subject have any thoughts on this and the effects of looking at bright spots of light in general? Call it BS, call it what ever you want, I want to hear your opinions. :D

Note: I am in no way advocating looking at or into a laser beam in order to improve eyesight. Don't do it!

-John
 

AUS

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Hi John,
Nice to have someone on who is closer to me than Sydney or Melbourne!
Maybe your eyes are just trying harder to focus on the spot and its excersizing the muscles or something? I find my eyes are more fatigued when looking at lasers if anything. I hope you have eye protection?

Andrew
 

TheDukeAnumber1

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My eyes also feel fatigued after looking at the dot for too long, but that's an interesting though FlatCactus. I would lean more towards being hyper aware of your vision but everyone is different.
 

DrSid

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It's simple .. by looking at bright object, your iris contracts to limit amount of light entering eye. This effectively decreases aperture size of your eye and improves 'depth of field' of your eyes, same way as if using higher stop number on camera.

For this to be noticeable, you must have less then perfect sight though. For people, who cannot focus well at large distances, the effect can be rather strong. I'm one them, so I know.

People with perfect sight can focus perfectly to any distance. Improving depth of field should have no effect on their vision sharpness. They might notice difference in depth of their focus zone, but since it's very hard to look at things outside your focus point, it's really hard to notice.

There are other ways how to test it. On bright light condition you will see better then in poor light. You can find label in distance you can almost read at evening .. and come back again during full sunlight, to check if you can read it again.

Also if you squint your eyes, you will see better, and this works the same way .. most people use this naturally to improve they sight. Squinting is especially effective in poor light, but it has almost no effect in full light (as the iris is very small anyway, and squinting won't change the aperture.

So simply said .. small holes see sharper .. lasers makes your iris hole smaller.

PS. it should also be noted that decreasing aperture size decreases amount of light, and it also increases diffraction limit of the optical system. Eye can handle low light rather well, and iris wont contract to diffraction limit to be noticeable, so it's not problem. But you can diffraction limit by looking through different sized holes in aluminum foil. Use needle or pin to make 0.5mm hole (normal pin width). That should be more or less diffraction limit of human eye focal length and should give you rather sharp vision over all distances, even for people with bad vision .. or you can borrow your mom's glasses to simulate bad vision.
If you decrease the hole size further, picture will be more and more dark (no surprise here) but also more and more blurry over all distances and even for people with perfect sight (or corrected bad sight). That's diffraction of light kicking in, your 'optical system' cannot capture the spatial information any more.
 
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Cyparagon

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Your activities can have a small effect on your quality of vision. If you spend all day in front of a computer, your vision tends to slowly progress towards near sightedness. Whereas if you work in construction for example and are constantly looking at things far off, you are more likely to keep your long-distance vision. There's actually some truth to the stereotypical "nerds wear glasses" for that reason.

If the effect you're describing isn't psychosomatic, it's because you're simply looking at things far off more often, and has little to do with the laser itself.
 
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You make some good points DrSid, I've used the hole trick when I don't have my glasses, except I curl my fingers to make the tiny hole.

I think you've hit the nail on the head Cyparagon. However I don't believe it's as applicable for just a few minutes of lasering a day.

Also, To answer the safety questions no, I don't have goggles yet (they're in the mail). I use the laser for sky pointing as we'll as around the backyard on diffuse surfaces. I'm not going to try and burn things with my eyes open without using goggles, that's just asking for blindness.
 

DrSid

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You make some good points DrSid, I've used the hole trick when I don't have my glasses, except I curl my fingers to make the tiny hole.

I think you've hit the nail on the head Cyparagon. However I don't believe it's as applicable for just a few minutes of lasering a day.

Also, To answer the safety questions no, I don't have goggles yet (they're in the mail). I use the laser for sky pointing as we'll as around the backyard on diffuse surfaces. I'm not going to try and burn things with my eyes open without using goggles, that's just asking for blindness.
You can check this with some friend .. let him watch the dot and turn laser on and off again, and watch his eyes from close. Iris dilatation should be well visible.
 




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