Newsgroups: bit.listserv.scuba-l
Date:         Fri, 8 Jan 1993 18:16:04 +0100
From:         Han Weegink <weegink@ICT.NL>
Subject:      diving with contact lenses

WILMOT@VAX.BIO.LEEDS.AC.UK writes :

>
> Regarding diving with contact lenses. I wear contact lenses whilst diving,

me too

>when you have your mask off both prior and subsequent to diving. The comment
>about having to spit on your lenses is nonsense. Contact lenses will not fog
>up due to being underwater with a mask on.

Not completely true. I don't know what you mean exactly by spitting on your
lenses, but I've heard from a number of people they were having problems with
fogged up lenses. BTW, I have had the problem myself occasionally. It seems
like it only happens if I get salt water in my eyes e.g. at the start of the
dive. I guess it causes some sort of dehydration problems.

>They are in the same environment
>as they normally are. Fogging up of masks is exactly the same as the fogging
>up of glasses...water vapour in the air contacting the cold glass surface and
>condensing. Lenses, which sit in the fluid at the front of the eye, are not
>subject to this phenomenon.

Fogging up of contactlenses is not caused by condensation of water vapour,
but excess proteins which is formed in the fluids of our eyes. Spitting on
contact lenses thus won't do any good, you'll have to do something else to
get rid of the proteins.

>A final note. An article in Dive Training on
>ways to correct vision in diving
>said that even if you have to open your eyes with lenses in, it is still
>unlikely that they will come out. Of course I have never tried this out. To
>me the advantages of diving with lenses far outway the possibility that one
>day I will have to open my eyes in water and lose one.
>

It all depends (it always does, doesn't it B-). I've been diving with
lenses, eyes open, many times and I've never lost a lense. But, (non-diving)
friends of mine have lost lenses when simply blinking their eyes.

The chances of loosing a lense depends on the degree to which a lense
sticks to the eye (which depends on the fit of the lense, the amount of
eye fluid between lense and eye, the material, size and shape of the
lense (not all are circular), etc.) and the exterior forces applied to
the lense (water movements, eye movements, objects poking in eyes (ouch!),
etc.etc.etc)

Also, in general, soft lenses have less chance of being lost than hard
lenses. Gas permeable lenses are probably safer than normal hard lenses
(are they still sold ?), but less safe than soft lenses.

Final remarks:

These are my personal experiences, and what I've heard from others. I've
had contact lenses for more than 10 years now, and never lost one.
I wear them while snorkling, scuba diving but also when dinghy sailing
and surfing (the latter two are IMHO a much greater risk of losing
a lense).


Han Weegink
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