Contact lenses and diving -Questions Welcome - by Idocsteve

[idocsteve]

I was going to say "Ask Jon about this one".

 

[idocsteve]

Via pm:

Hi Steve,

I wear contact lenses (monovision) as follows: (my lens Rx is current)

Ultraflex II Aspheric

Right-D-6.50 (BC 8.6, DIA 14.2) . I also have some lenses that are D-7.00 which my eye doctor said may help seeing underwater through the scuba mask. It helps a bit but sometimes the smaller characters on my Dive computer are a bit difficult to discern.

Left-D-4.75


I read about these Dive Optx lenses which I believe are attached to the scuba mask. Would these help and if so do I need to get a particular strength?

Also, is it practical to wear my regular eyeglasses under my mask instead of using my contact lenses?

Any advice will be appreciated.

My response:

You can't wear your regular glasses under your mask because the temples would break the mask seal. Contacts are the way to go, I don't know why your doc suggested wearing -7.00 if your Rx is -6.50.

I can't advise you on the stick on lenses, I have no knowledge in that area. Since you're already a contact lens wearer, two good options to speak to your doc about include bifocal contact lenses or cutting back the full distance Rx in your nondominant eye so you can read with that eye, this is called monovision.

 

[rj5620]

I suggest you confirm your "reader" diopter need in VERY dim light. It may be closer to +2.5.

Diopters are a metric unit of measure. Put a +1 on a camera lens that's focused at infinity and 1-meter is what's actually in focus; +2 w/lens @ infinity = 1/2 meter in focus; +3 = 1/3 of a meter in focus, etc.

Submerged, objects appear BOTH 33% bigger and 25% closer – both are true simultaneously (PADI's Encyclopedia of Diving gets the facts wrong - it's not "either," it's both at the same time). This magnification is why true angle-of-view gets so narrower underwater. Both magnification and lateral chromatic aberration is not uniform but gets worse as you look off-axis (i.e. away from where your nose is pointing):


To precisely compensate for underwater magnification, bifocal diopter is adjusted for that 25% reduction in distance (e.g. +2 in air = 500 mm in focus; reduce that distance by 25% = 375 mm, requiring 2.66 diopter; but ophthalmic lenses only come in .25 increments). Also, the "vertex" distance (cornea-to-inner-surface of lens) of a dive mask lens is further than a spectacle lens, which requires a reduction in a positive lens (like holding a magnifying glass further from your eye). Bifocal strength is HIGHLY subjective: the stronger the bifocal, the narrower the view, and arm extension can easily position objects for a best compromise position.

That's a very detailed technoidal way of saying:
1. Confirm what you need in VERY VERY VERY dim light above water
2. Add 0.25 diopter, unless...
3. If you're a photographer needing to confirm critical focus on an LCD screen, use +0.50 extra on one eye (each eye does not need to be the same strength because you don't see through them both at the same time anyway, per post #126).

Now, all that said, the "magic bifocal" phenomenon of dome optics is why hundreds of divers wear contact lenses to use some of the 9,000 double-dome masks we've shipped around the world since 2003. You get great close focus AND distance vision in the entire field-of-view (i.e. your eyes behave as they did when you were in your 20's).

I am confused about vision correction and these "domed masks". Does one need to wear their distance correction (-2.00 right and -2.00 left) in the form of contacts and the "domed" phenomenon takes care of near vision? or does the mask take care of everything without the use of rx lenses of any type?

Thanks

 

[Kevrumbo]

idocsteve --my keratoconus OU is too steep and now having trouble tolerating "piggybacks" (i.g. combined soft and hard contact lenses).

Now considering phakic collamer Intra-Ocular-Lens Surgery:
Visian ICL Implant and Verisyse-Artisan Lens IOLs

 

[Diver0001]

Idocsteve,

How bad does it get? I've reached "that age" and my eyes are starting to get that aging thing happening.

I fried my eyes at university but only needed a +1 for the longest time and only when i was reading. In the last few years it's gone to +2 (right on schedule). Does that mean if I live to be 80 that I'll need a magnifying glass to see my own hands by the time I'm 60?

R..

 

[jcm1911a1]

As a result of a parasitic worm in my eye (now dead!), I have double vision (LOTS of retinal damage). I have to use tape, or a spot patch my optometrist did for me, on glasses. Doing this takes care of the double vision, while giving me some peripheral vision. The vision in my good eye is 20/20, the bad eye is now 20/35, down from 20/160. I am showing improvement, and only need correction for reading. As I am showing improvement, I don't want to do anything permanent or damaging to my mask. This was discovered only 5 months ago, and my doctors tell me I could see improvement up to a year later. My question is this: what can I use in/on my mask to help me? It would have to be able to withstand salt water and de-fog

 

[idocsteve]

idocsteve --my keratoconus OU is too steep and now having trouble tolerating "piggybacks" (i.g. combined soft and hard contact lenses).

Now considering phakic collamer Intra-Ocular-Lens Surgery:
Visian ICL Implant and Verisyse-Artisan Lens IOLs

I hope that works out for you if you decide to go for it. No guarantees, like anything else, it's all risk/benefit ratios. If you're not functioning well then you gotta ask yourself what's the worst that can possibly happen as a result of the surgery. Better yet ask your surgeon, and do some independent research. Any surgery is risky, experimental, new technology surgery on unpredictable conditions such as keratoconus can be even moreso.

Idocsteve,

How bad does it get? I've reached "that age" and my eyes are starting to get that aging thing happening.

I fried my eyes at university but only needed a +1 for the longest time and only when i was reading. In the last few years it's gone to +2 (right on schedule). Does that mean if I live to be 80 that I'll need a magnifying glass to see my own hands by the time I'm 60? .

You didn't "fry your eyes" at university. They would have lost their accommodative function regardless of what you did with them, but many people think that reading a lot, in dim light, or wearing glasses too much, or not wearing glasses too much, or masturbation, or a host of other things, causes loss of vision, and that's just not true.

You'll be able to see your hands at 80 however you might not be able to count your fingers and even if you could you'd probably forget how many you had by the time you got to 5.

the bad eye is now 20/35, down from 20/160. I am showing improvement, and only need correction for reading.

You mean that your vision is up from 20/160 to 20/35, that's a huge improvement.

As I am showing improvement, I don't want to do anything permanent or damaging to my mask. This was discovered only 5 months ago, and my doctors tell me I could see improvement up to a year later. My question is this: what can I use in/on my mask to help me? It would have to be able to withstand salt water and de-fog[/QUOTE]

It sounds like you might be able to use one of those press on bifocal stickie things. I don't know anymore about them than what I have read here on ScubaBoard.

 

[Diver0001]

You'll be able to see your hands at 80 however you might not be able to count your fingers and even if you could you'd probably forget how many you had by the time you got to 5.

Acutally, some days I already have that... LOL

I was actually wondering though, in all seriousness, if the worsening of ones sight is something that slows down at some point or how that works.... ? any insights?

R..

 

[idocsteve]

Acutally, some days I already have that... LOL

I was actually wondering though, in all seriousness, if the worsening of ones sight is something that slows down at some point or how that works.... ? any insights?

R..

By the early 60s you've lost pretty much all your nearpoint focusing power. The good news is, that's about as bad as it's gonna get, the bad news is, it's going to be very blurry and you won't be able to see much at near without your glasses, and of course as you get older there is a greater chance of developing an ocular pathology which will reduce your vision that much more.

 

[Diver0001]

terrific :depressed:

Thanks for your thoughts, though. I appreciate it.

R..