foggy prescription

[edmundsteele]

I am a new diver and have just assembled a mask with an "attached" eyeglass prescription - my prescription precludes glueing a lens directly to the mask faceplate. Anyway, I now have 3 glass surfaces between my eye-balls and the water to fog up, which they do very well - the glass surfaces that is.
Has anyone any experience with defogging this kind of optical rig? It's kind of hard to get between the prescription lenses and the faceplate. There is only about 1/8th. inch air gap.

 

[Tractor Tom]

I rigged a similar rig many years ago in Hawaii, when I started snorkling, and later diving. Had some lenses out of an Army issued gas mask rigged to a mask. I found the same issues, and finally went and got a prescription ground mask at the Marine BX. I wore that old mask for more than 20 years, worth every cent. Finally this season, I got a new mask with a set of ground lenses. These are NOT the bonded lenses, but prescription ground glass lenses that replace the original mask lenses. I have found these to work the very best for me.

Sorry I wasn't much help. There are some commercial anti fog liquids that you can squirt in your mask and rinse out, before you dive, but with the additional surfaces, I don't know how well they will work.

 

[edmundsteele]

Thanks Tom,
I will try some more of the commercial anti-fog solutions. So far, what I have tried has not worked too well.
My optometrist is coincidentally an experienced cave diver and based on his advice, I feel reasonably sure that replacing the original mask lenses is not an option for me. ;-0

 

[SubMariner]

No offense, but glueing lenses inside masks is really not efficient. The best idea would be to send your mask & prescription to someone like Sea Vision & have them grind lenses for your mask.

Not only would you eliminate the problem you described, but also would have a more optically correct prescription for diving; optics U/W are NOT the same as above water.

~SubMariner~

 

[edmundsteele]

Submariner,
The set up I have looks like the front of a “regular” pair of bifocals (so I can read the gauges) made of the fancy bi-convex high-index plastic lenses in a thin nylon frame. The bridge of the frame has a small tab that extends and is glued to the inside glass of a one-piece mask. I have been told by three different opticians, that to go to a glass lens at mask width as you suggest, the suckers would have to be about an inch thick in the middle. The current rig works great for seeing for a few minutes, the optics are the same as “above water” since there is air on the both sides of the lens. Then it fogs up………

 

[SubMariner]

Seavision does bifocals too. I know.. I have a pair and so does my husband.

The lenses are not glass, BTW.

~SubMariner~

 

[Dee]

SubMariner once bubbled...
Seavision does bifocals too. I know.. I have a pair and so does my husband.

The lenses are not glass, BTW.

~SubMariner~

~Sub~...are you sure SV lenses aren't glass? I thought only glass could be ground.

Their website says "Our patented system involves one-piece precision ground lenses customized for your particular prescription." But they don't specifically say glass.

MMmm??? Whatever it is, it works! Very hardy too. I'm sometimes not the most careful with my mask and I've never had one even get scratched lenses. Another reason I think they are glass.

 

[Tractor Tom]

Guys,

As a fellow who has been wearing rather thick glasses his entire life, I know that plastic can be ground and polished into lenses, the glasses I'm wearing now have plastic lenses and are much lighter and easier to wear than glasses with glass lenses. I also know that the prescription lenses in my mask are glass, as were the original factory lenses they replaced. Can you get plastic prescription lenses for a mask? I don't know the answer. By the way, the lenses in my new mask are about 3/4" thick along the edges where the lenses are thickest. As long as the edges can be ground down to fit in the mask, the thickness isn't important. I know mine had to go back to the shop, as the edges were too thick the first time, and wouldn't go into the mask. The comment of one of the diveshop guys was,"you must be really blind!" I thanked him, and told him that my eyes were healthy and in good working order, simply badly shaped....

As for the fogging problem, the simple answer is to dive with a little bit of water inside your mask. As the lenses fog, roll your head around and wipe the fog off with a puddle of water in the mask. Not a high tech solution, but one that always works if you can get used to your nose being in the water all the time....

 

[scorpionfish]

The best and highest tech defogs usually need a little help after a mask has been used for a while. The "traditional" approach is to use a VERY mild abrasive such as Softscrub or toothpaste every once and a while. However, your problem requires a more subtle approach.

I suggest you cleanse your mask with 409 Cleanser. Then use that ultrahightechdefog, Johnson's Baby Shampoo. This should remove all the stuff which is causing your problem. Stay away from saliva (known as "spit" to the macho crowd) and anything that might leave a residue. By the way, seawater does leave a residue and washing your mask with fresh water after diving is very important. For those among you who are like the Detective Monk, distilled or deionized water is an even better solution: I use it for both my mask and my cameras regularly.

If this works for you--and it has for me--do what I do: carry some little plastic bottles of these precious liquids aboard your dive boat: then they are available should the problem occur during a dive trip.

Scorpionfish

 

[SubMariner]

Yes, they are plastic Dee. They are far too "light" to be anything else, esp since they are bifocals. Also, Seavision cautions against using any abrasives on the mask as the lenses could scratch. Ergo, nothing stronger than toothpaste ever gets used on our Seavision masks.

As for de-fogging masks. I agree that you have to start with a CLEAN surface INSIDE the mask, otherwise NOTHING will work. That usually entails at least two cleanings with regular toothpaste (not gel). It should have that "squeeky clean" feeling inside once you are done.

I am loathe to recommend using anything stronger, with the exception of glass cleaner that is specifically made for eye glasses. There are too many chemicals in those other cleaners that may injure your eyes, even if you do "rinse thoroughly". They're simply not made to be in close proximity to your eyes.

Ultimately, I find that once the mask lenses are clean, baby shampoo works as well as any of the commercial concoctions. Put a drop on the lenses, spread it around with your finger, then lightly rinse. That will leave enough of a "film" on the inside of the lenses to keep fog from forming.

Eventually, however, the cleaning process needs to be repeated.

~SubMariner~