UKC

Anyone had experience of using Continuous Wear contacts above 8,000m?
I've had no problems at 7,000m with same pair OK for over a month.
Thanks

In reply to ian2u:

I used daily contacts on Everest and had no problems. (the kind you take out each night and use the same pair for a fortnight) I had only been using them for about 6 weeks before the start of the expedition.

My friend wore continuous wear contacts and also had no problems (the kind you wear for a month at a time and never take out).

However, I have heard that there can be problems so have a read of this:
http://www.basecampmd.com/expguide/snowblind.shtml
That suggests that it might be problematic, so maybe we were lucky?

In reply to ian2u: Well that's another reason not to have laser surgery. According to that link you're knackered over 3000m!

In reply to ian2u:

Even the best continuous wear contact lenses limit amount of oxygen getting to the eye. My optician advised that even though you can wear the lenses continuously it is best to take them out when you don't need them, i.e. in the evening/when asleep.

In reply to TimR:

I'm sure pro aviators can now fly after having laser surgery. So it cant be that bad.

In reply to BennyC:

Airplanes are usually pressurized to around 2400m?

In reply to ian2u: Sorry I've read it again. They're talking about actual surgery where they correct the vision using a scalpel. Laser surgery is apparently a bit more stable and OK up to 7000m. The US navy are still studying it. Not worth the risk to me yet though.

Imagine going blind in the rare occurence that a plane depressurizes. Not fun!

In reply to TimR:

When I have time I will find an article I read on this. I did a bit of research for some Singaporean buddies. It may have been in Medicine for Mountaineering. From memory, there are basically two types of laser surgery? One is ok for HA climbing and the other more problematic.

In reply to ian2u:


In general longer term wearing of contact lenses (continuous wear)even at ground level is associated with an increased incidence of keratitis, corneal ulcers, erosions etc.So I would be concerned about wearing contacts all the time above 5000m or so.

I wore my normal gas permeable hard contact lenses on Denali, and indeed did find that the contact lens solutions became like glue at higher camps.To that end I kept the contact lens bag in my sleeping bag next to my body(along with inner boots, water bottles etc).I also did take my glasses with me.I was always the last person into my sleeping bag, as I took painstaking efforts to keep the contacts exceptionally clean and uncontaminated.Before cleaning them I would wash my hands twice, and certainly would not just use the alcoholic gel that many use at altitude.

I went to a lecture at the Royal Society of Medicine on ocular problems at altitude a couple of years ago.From what I remember, both radial keratectomy, and LASIK were problematical at altitude, whereas another technique was less so.Even that did not sound so perfect.At that point I decided to keep my corneas as they are for now.

Everybody's corneas get thicker with altitude, but after a while this is not so pronounced.From what I remember the same occurs with intraocular pressure, i.e. it gets higher, but then there is an adjustment or homeostasis, that results in the pressure not being so high.

Certainly if I get the chance to go to the higher mountains, I will review all the literature/references on these topics before going.

Whatever the case, I would not advise wearing contact lenses for such an extended period of time.

Regards
Rob

In reply to TimR:

Hhmm - think you need to re-read this article - put yer glesses oan this time

In reply to TimR:

Quote:
"The most commonly performed laser refractive surgery at present is laser in-situ keratomileusis (LASIK). Several studies observed climbers having undergone LASIK and the authors’ conclusion was that LASIK may be a good choice for individuals involved in high altitude activities, but those achieving extreme altitudes of 7927 m (26,000 ft) and above should be aware of possible fluctuation of vision. Data suggest that a small refractive shift in the myopic direction may be present at extreme altitudes. Climbers who do not ascend beyond moderate altitudes should not experience a post-LASIK refractive shift."

From that link - last paragraph.