Dr. Cheung’s Blog 8/14/2017

Dr. Cheung’s Blog 8/14/2017

August 14, 2017

Climbing Mount Rainier

Sometimes we do things without quite knowing the motivation behind them.  I am not talking about things that we do on a whim.  Rather, they are things that take months of mental and/or physical preparations; they can be costly and even risky.  Climbing Mount Rainier is one of those things for me and I am proud to say that I summited Rainer (14,411 feet) on the morning of June 23.  And I am never going to do something quite like that again.

To put things in context, you should know that I am a guy who likes his hot shower and firm mattress.  Camping has never been my thing.  So, when my wife (then fiancé) challenged me to climb Mount Baker (10, 781 feet) six years ago, I did so with much trepidation.  The conditions we had on Baker were awful, cloudy and rainy pretty much the whole time with limited visibility.  Sleeping on ice was no match to my Serta.  I swore I would never do something like that again after Baker.

But Mount Rainier keeps calling me.  It has a magical quality to it that is hard to describe.  Every time I see it from a distance I wonder what it is like to be up there on the top.  I just have this inkling to say that I have been up there.  So, when my good friend Jon decided to climb Mount Kilimanjaro in Tanzania this summer, I said why don’t we get you ready by climbing the one in our backyard together.  So, for six months, I trained myself on a treadmill or elliptical machine with a 40 pounds backpack, along with other weight bearing and cardiovascular exercises.  Jon and I also hiked up and down Mount Walker in Quilcene a few times as the “real life” preparation.  But nothing can prepare us for the altitude of Rainier.

We went with an outfit in Seattle, Alpine Ascent, and they were excellent.  We gathered at their office in Queen Anne at 5:30 AM and they bused us up to Paradise (5400 ft) which was still covered with snow.  Eight climbers and four guides then steadily ascended the mountain, pausing for a quick break every 1000 feet.  The last leg before we reached Camp Muir (10,188 ft) was a slow, hard slog.  We were awarded with an amazing view at the camp though, taking in the majestic Mounts Adam, Jefferson, and Baker in one fell swoop.  I thought I should be hungry that night but I was not.  We retired to our shack at 6:30 but I got two to three hours of sleep max that night.  In retrospect, I probably had a mild case of altitude sickness already at that point.

The second day was easy.  We had snow school in the morning, learning how to use crampons and ice axe for self-arrest.  We ascended only another 1000 feet in the afternoon to Ingraham flat with the rest of the day to relax.  Again, I had to force myself to swallow the delicious chicken sandwich and I slept even less that night.

On summit day, we got up at 1:30 AM, put our gears on with our headlamp and started our ascent to Disappointment Cleaver.  It was a rocky, treacherous, and narrow path and we had to hang on to a rope that was bolted to the mountain for security.  Except for the three to four feet in front of me that was illuminated by my headlamp, it was pitch black.  Dawn came right when we reached the top of the Cleaver and the view of the sunrise was uplifting.  The last two thousand feet of elevation gain was a bit of a blur for me.  I literally got short of breath every couple of steps and I was glad that the guides were stopping frequently on our path to put pickets in the snow for safety.  I was completely drained the last hundred feet or so before the crater and Jon was kind enough to give me a tug on the rope to carry me over.

The crater was covered with pristine thick snow that was eerie and peaceful at once.  I was so tired that I literally collapsed on my backpack and barely had the energy to enjoy the view.  It was extremely windy up there and as soon as I muster up the energy to stand up, I was ready to go back down.  It was at that point that I realized I was only half way done with the trip and I was already out of gas!!

The descent was easier physically but demanded even more mental focus with our footwork.  When we got back to Disappointment Cleaver, I saw that on the other side of the narrow path was a sheer cliff to crevasses that are a few hundred feet deep below us.  I was panic stricken but I was so thankful to my guide Rachel who was so reassuring and talked me through it.  The rest of the descent was less adrenaline provoking, punctuated only by periods of pure joy of gliding on my butt.

I did not gain back my appetite until a day or two later.  My thigh muscles were cramped and my nasal passages were clogged for days.  My skin started to peel in unexpected places: bottom of my nose, my chin, my ear lobes and in the folds of my ears, all the spots that I was not diligent in applying sunscreen.  I also looked a bit like a raccoon with my unburnt skin color under the glacier glasses.

Mountaineers are exposed to higher than ordinary levels of UV radiation, both because there is less atmospheric filtering and because of reflection from snow and ice.  There are three classes of UV light.  UV-A contains wavelengths from 400 to 320nm, UV-B with wavelengths from 320 to 290nm and UV-C contains wavelengths below 290nm.  The ozone layer absorbs almost all UV-C coming from the sun.  Of the total solar radiation falling on earth, approximately 5% is UV light of which 90% is UV-A and 10% is UV-B.  UV exposure increases by approximately 10% for every 1000 feet of elevation gain and fresh snow is particularly reflective, bouncing off 60-80% of incident light compared to 15% with sand and 5% with water.

UV damages living tissue in two ways.  First, proteins, enzymes, DNAs and cell membrane components absorb UV lights and break their molecular bonds.  Secondly, UV light can generate free oxygen radicals which in turn can damage molecular architecture of our tissues.  The most common eye problem associated with mountaineering is snow blindness.  The corneal epithelium (the skin of cornea) is highly susceptible to injury from UV light.  There are no symptoms during exposure but pain and gritty sensation gradually developed a few hours later when the injured epithelial cells shed.  Even though the condition is self-limited and usually resolves within 24-48 hours, it can have a huge impact to the climber and his/her team.  Treatment is with patching, dilating drops and antibiotic ointment.

The relative lack of oxygen and the drying effect from increased evaporation of the tears at high altitude can also cause the cornea to swell.  This is particularly problematic with contact lens wearer.  Persons who had previous refractive surgery (radial keratotomy) may also become far sighted and impair their performance at high altitude.  At extreme temperature cornea freezing and eye lash freezing are also possible.

Retinal hemorrhages develop commonly in people when they are at extreme high altitude (26,000 feet) but can occur in lower altitude.  Most do not affect vision but can be problematic if they are located in the macula, the central part of the retina.  There is also an increased risk of a stroke in the central retinal vein because of an increase in the viscosity of the blood at high altitude.

For those of us who are not mountain climbers, long-term exposure to low dose of UV light is associated with a host of eye disorder.  Cataract is by far the most common problem but eyelid tumors (actinic keratosis, basal cell, squamous cell and melanoma), scar tissue and even cancer on the coating of the eye (pinguecula, pterygium and conjunctival intraepithelial neoplasia) can develop.  Prevention is the key with sunglasses wear.  Almost all dark sunglasses absorb 70-80% of the incident UV light.  Not only do they prevent ocular tissue damages but also allow for better visual function.  They can improve contrast, enhance the retina adaptation to darkness and reduce glare sensitivity.

If you are planning to watch the total eclipse on August 21, regular sunglasses will not cut it.  You must wear eclipse glasses and/or handheld solar viewers that have been verified by an accredited testing laboratory to meet the ISO 12312-2 international safety standard for such products. For a list of reputable brands, please consult the NASA website at:  https://eclipse2017.nasa.gov/safety

Solar retinopathy is photochemical injury that can be caused by direct or indirect viewing of a solar eclipse.  Visible blue light and UV light are the culprits.  Younger patients with clearer lenses and patients taking drugs that photosensitize the eye such as tetracycline are particularly vulnerable.  Do not let your children watch the eclipse unsupervised.  Within hours of unprotected solar eclipse viewing, patients may experience decreased vision, blind spot in the center of the vision, change in color vision, distorted vision and headaches.  Visual acuity is typically mildly reduced to 20/25-20/40 but can be down to 20/100, depending on the duration of exposure.  Most patients recover after 3-6 months with vision improvement to 20/20 to 20/40 but the central blind spot may persist.  On examination, a yellow-white spot can be seen in the fovea, the very center of the retina, in the first few days after exposure.  The spot typically becomes reddish after several days with a pigmented border.  There is no known treatment for solar retinopathy and prevention therefore is the key.