Altitude blindness

Discussion of medical or rescue topics related to climbing and mountaineering.
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Altitude blindness

by courtSchurman » Sat Oct 07, 2017 4:11 pm

I have an east coast client who did a late season climb of Rainier 2 weeks ago and felt strong and prepared; however, around 13-14000' she experienced blurred vision and then felt like she was going blind. The guides sent her down before it could get any worse, and she gradually felt better and better, and 2-3 days later had no residual effects. The guides suggested she visit an eye doctor, which she planned to do as soon as she could get an appointment, but she's on the east coast and wasn't very hopeful that anyone there would know too much about AMS,HAPE, and HACE much less altitude blindness.

Anyone know anything about altitude blindness? I read people can be affected as low as 4300 meters / 14,000' but I've only ever read about it becoming serious on 8000m peaks. She's especially curious whether Diamox would help in the future.

Input / suggested reading much appreciated.

C. Schurman
Last edited by courtSchurman on Fri Oct 13, 2017 4:11 pm, edited 1 time in total.

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Re: Altitude blindness

by asmrz » Sat Oct 07, 2017 8:45 pm

First, I'm not a doctor, nor am I in the medical profession.

There is snow blindness caused by inadequate snow glasses/goggles. The remedy is glasses or goggles which allow no more than 5 percent of visible light through.

There is also snow blindness which is part of HACE. Some of the brain swelling (due to HACE) affects the nerves behind one's eyes and is responsible for gradual loss of vision. That is (if I recall correctly) just one part of HACE.

There are people quite sensitive to altitude who can feel the effects at 5-6,000 feet. One does not have to go high to start feeling it. Some people are affected by elevation, others are not.

Any Houston books (Going High, Going Higher), also Medicine for Mountaineering deal with the issue. I'm not sure, but I think snow blindness is not an isolated event. Other HACE symptoms will likely be occuring as well and at the same time.

BTW The guides were on the money to send her down.

I'm not sure if Diamox alone could resolve this problem. Diamox offers some relief to those who have fairly light problems adjusting to elevation. Your description of the problem sounds way more serious. If it really is HACE, I would be very careful about going up again.

I hope other people chime in. This is a very interesting subject.

BTW There are no 14,000 meter peaks anywhere on Earth.

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Re: Altitude blindness

by markhallam » Sun Oct 08, 2017 7:33 pm


I am a Doctor and I wrote a page on Expedition Medicine in the articles section of SP but I cannot add much more than asmrz. But I would comment as follows:

Certainly snow blindness can be a cause of (thankfully usually temporary) blindness, but this is easy to diagnose accompanied as it is by intense pain described as like having red-hot iron fillings underneath the eye-lids. It is basically sun-burn of the front of the eye - similar to the 'Arc Eye' which welders get if they forget to wear eye protection. I would imagine the guides wouldn't miss this and also expect would ensure their clients wore adequate eye protection.

HACE (High Altitude Cerebral Edema) is not linked to snow blindness but refers to a condition of swelling of the brain in response to low oxygen levels. More commonly this presents with headache, nausea & vomiting (yes, same as Acute Mountain Sickness) but goes on to include confusion, emotional changes, collapse - and (without treatment - usually including descent) ultimately death. Swelling of the brain can involve pressure on the occipital lobe at the back of the brain - which is the visual centre is sited - and thus slowly progressive blindness can and does occur. But there would always be the other and very worrying symptoms. Again, experienced guides would be aware and would be unlikely to miss this very serious diagnosis.

There is another possibility: that is that at altitude it is normal to develop a little bit of edema (excess tissue fluid leading to swelling of tissues) generally. This can be seen in the skin with the puffy eyed look and mild finger/toe swelling that some notice on going to altitude. This is only a problem if it becomes severe and/or is associated with fluid build up in the brain (HACE as above) but also in the lungs (High Altitude Pulmonary Edema or HAPE). Why this is relevant is that this minor swelling can effect the tissues of the eye - resulting in corneal swelling ( i.e. affecting tissues at the front of the eye). My understanding is that the effects are not usually enough to result in noticeable loss of vision. BUT this is different if you have had refractive (corrective) eye surgery. Again, my understanding, is that vision becomes increasingly blurred with increasing altitude (haven't heard of problems below 4000m) - but effects reverse on descent. But the effects can become so severe that there is no choice other than to descend (as is the general rule with altitude complications, apart from mild AMS, when symptoms may resolve enough to go higher, after a rest at a given altitude).

Had this lady had refractive surgery? Did she have contact lenses? I don't have any knowledge of contact lenses at altitude but I could imagine some types may perform differently with reducing air pressure.

In terms of taking Diamox (acetazolamide) - interesting idea. The primary purpose of this drug is to reduce pressure in front chamber of the eye (thus treating a medical condition known as Glaucoma). It is kind of a lucky side effect that the same drug can relieve symptoms of mild AMS and slightly ease the process of acclimatisation (important note: NOT a substitute for a measured acclimatisation program as per UIAA guidance). However, I do not know if this would help corneal swelling - probably not. It might mitigate the effects of corneal swelling. BUT I would not recommend trying this without seeking advice from a specialist in ophthalmology. I am a specialist in addiction medicine with a general practice background and although I have an interest in high altitude medicine I have no specialist knowledge of eye conditions.

Thus overall I agree with the guides advising descent - and seeking the advice of an eye doctor. Are there any eye doctors using SP?

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Re: Altitude blindness

by rgg » Mon Oct 09, 2017 3:05 pm

The (excellent) article that Mark is referring to is Expedition Medicine.

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Re: Altitude blindness

by courtSchurman » Fri Oct 13, 2017 4:11 pm

Thanks all. Yeah, typo on my part, 8000 m / 14000 FEET. Doh.

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Re: Altitude blindness

by ExcitableBoy » Sat Jun 23, 2018 2:44 pm

Hi Courtenay,

John Roskelly, who had previously climbed K2, Dhualguri, Makalu, and other big peaks sans oxygen, went blind while attempting the Cassin Ridge on Denali. He attributed it to a type of HACE brought on by climbing too quickly without prior acclimatization, and that was below 20,000 feet.

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