Question Prism Correction for Dive Masks?

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tursiops

Marine Scientist and Master Instructor (retired)
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I have developed strabisbus, my eyes do not point in quite the same directions...one points down relative to the other. Double vision is the result. This is correctible in glasses with a "prism" correction, basically a wedge that bends the light in one direction. This is usually done by taking the measured amount of correction needed (in my case 6 diopters) and putting half in one lens (3) and half (of the opposite sign) in the other eye...so two corrective lenses are needed. This can be done with ground lenses, or stick-on Fresnel lenses. Has anyone used a prism correction in their dive mask, either ground or with stick-on Fresnel lenses?
 
Any chance you were able to find a make with prism correction included with the prescription?
 
Google is your friend. You do not want Fresnel prisms as mentioned in the Op. They are thin, because they're composed of many tiny individual prisms that have an additive effect, they are manufactured on a translucent media that is designed to stick to an eyeglass lens, and due to the composition and demarcations between the individual prisms, the vision is severely degraded. Or to trial the patient to determine the minimum amount of prism to enable them to fuse the image with both eyes. They are intended for temporary use only such as following a stroke while the patient is being rehabilitated and the strabismus is (hopefully) temporary, or when the required prism correction is so great it's not possible to fabricate an eyeglass prescription to accommodate the required amount.

 
Any chance you were able to find a make with prism correction included with the prescription?
SeaVision says they can do it, at least for certain masks and my prescription.
I tried stick-on Fresnel lenses and they were not satisfactory. I saw better without them!
 
I tried stick-on Fresnel lenses and they were not satisfactory. I saw better without them!
No surprise. You should have asked me first.
:cool:
 
Google is your friend. You do not want Fresnel prisms as mentioned in the Op. They are thin, because they're composed of many tiny individual prisms that have an additive effect, they are manufactured on a translucent media that is designed to stick to an eyeglass lens, and due to the composition and demarcations between the individual prisms, the vision is severely degraded. Or to trial the patient to determine the minimum amount of prism to enable them to fuse the image with both eyes. They are intended for temporary use only such as following a stroke while the patient is being rehabilitated and the strabismus is (hopefully) temporary, or when the required prism correction is so great it's not possible to fabricate an eyeglass prescription to accommodate the required amount.

$384. Just a tad expensive....
 
That is what the OP was. Sorry you missed it.
I didn't miss anything.

I'm sorry you didn't do your homework first and wasted time and money on worthless Fresnel prisms that are not designed for the purpose in which you attempted to use them.
 
I didn't miss anything.

I'm sorry you didn't do your homework first and wasted time and money on worthless Fresnel prisms that are not designed for the purpose in which you attempted to use them.
I do not understand. Fresnel prisms are routinely used by OD's to see if they work for strabimus before you spend the money on ground lenses.
 
I do not understand. Fresnel prisms are routinely used by OD's to see if they work for strabimus before you spend the money on ground lenses.
Exactly right. One of the two main purposes of Fresnel lenses is to trial the patient prior to ordering expensive ground prescription lenses. For diving they would be completely insufficient (even as a temporary trial sort of thing), given the greater demands involved with the decreased ambient lighting, shadows, poor contrast, and color changes at depth.

So it's no surprise you were dissatisfied. When I posted "you should have asked me first" with the sunglass smiley that was sort of a tongue in cheek way of saying "I could have told you that!"
 
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