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Plastic lenses

DeepAbyss

Active Member
Feb 11, 2018
105
0
26
atlantis
Hello,
I wanted to know if I make lenses at the optician with plastic prescription like normal eyewear.
Is this something possible?
Will it withstand the pressures? safe?
Like other plastic lenses mask for example the sphera mask.

thx
 

Leander

Member
Oct 17, 2017
77
21
23
36
Between here and nowhere
I can't see it working with the Sphera as it has curved lenses. So even if you would make a lens that fits, the view would distort when you look around with your eyes.

I have very bad eyes too. I just wear soft contact lenses icm a normal mask.
 
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DeepAbyss

Active Member
Feb 11, 2018
105
0
26
atlantis
I'm not talking specifically about the sphera, there are makses that have the option to replace prescription lenses.
I wanted to know if plastic lenses like eyeglasses if I put them in maskes would it work like plastic lenses in the sphera or need special plastic that will not fall apart under pressure.
 

Leander

Member
Oct 17, 2017
77
21
23
36
Between here and nowhere
As you should be equalising your mask on your way down there shouldn't ever be enough pressure to do damage to the lens. Should you swim down without equalising your mask, your eyes would give before a hard piece of plastic would.
If you would dive into the water head first, then stuff may break. That's why masks with glass lenses have a warning sticker on them.
Plastic tears instead of shattering. So I guess it's quite safe to experiment. The plastic used in masks is polycarbonate, which is a very tough material, but unfortunately scratches really easily.

Still I'd say that contact lenses are a better option, especially when spearfishing. Glasses only bend the light correctly when looking straight through the center, so you'd have to stare down a fish to get a good look. With contact lenses you can pretend to be looking away and still keep track of the fish. A second benefit is that you can use masks with glass lenses, which gives a much more clear view than than plastic.
 
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DeepAbyss

Active Member
Feb 11, 2018
105
0
26
atlantis
why if i would dive head first something bad can happen?

i have mares star ls with optical lenses of mares, i just want try to make plastic lenses be cause i can be more accurete about the plastic lenses because a opical made them.
i just wanna know if its can be any hazad on try it?
i saw the aqua lung made them plastic lenses from plexisol so i can try another plastic?

thx
 

Leander

Member
Oct 17, 2017
77
21
23
36
Between here and nowhere
Diving head first into water, I mean like the swimmers do, not like the diving we do, is about the equivalent of hitting your mask with a hammer.

But underwater nothing should happen really as the pressure inside and outside the mask should be kept the same. Search "equalising the mask". Of course, thin plastic bends easier than thick plastic, and bent plastic distorts the view.

Can a diy-mask break and hurt you? Probably. It's your own risk, and your own face, so make sure you stress-test everything extremely well before letting the mask even come close to your face, let alone use it in the water ar depth.
Also, unless you're very confortable in the water and under water without a mask, the mask can be considered as safety equipment, meaning: don't mess with it.

As for 'perfect vision'. In the water you will never have perfect vision no matter how hard you try and whatever gadgets you use. Floating particles, plankton, differences in salinity and temperature, the absorbtion of light by the water, etc. All those things limit or distort your view. For spearfishing, if you can see well enough to detect a moving outline on a similar colored background it's good enough. Detection by movement, contrast and shapes is what eyes are actually made for, reading small stuff far away is something humans invented and has no use in nature.
 
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