High altitude mountaineering and extended backcountry trekking present several ophthalmic challenges to outdoor enthusiasts, among which are problems with contact lenses, problems with previous corneal surgery, and UV induced keratitis.
More from basecampmd.com:
Removing contact lenses at night … presents logistical problems in the mountaineering setting. Practicing acceptable lens hygiene during an expedition is difficult. The mountaineer who leaves contact lenses in a case filled with liquid solution in the tent outside of his or her sleeping bag at night may awaken to find the solution and lenses frozen solid.
All contact lens wearers should have backup spectacles, and this exhortation applies especially to those who spend extended amounts of time in the wilderness:
Contact lens wearers should always have backup glasses available for use in the wilderness in case a lens is lost or becomes painful.
In the event of bacterial keratitis related to contact lens wear, specialists recommend carrying topical antibiotics during all extended backcountry excursions:
Individuals who wear contact lenses on expeditions should carry both fluoroquinolone eye drops and contact lens rewetting solution. Both types of drops may freeze if not protected from the cold.
Individuals who have had laser refractive surgery should be especially careful when exploring at high altitudes:
An acute hyperopic shift in persons who have had radial keratotomy (RK) and then experience an altitude exposure has been reported in past years, and has been observed at altitudes as low as 2744 m (9000 feet). A dramatic example of this phenomenon was that experienced by Dr. Beck Weathers in the Everest tragedy of May 1996 in which eight climbers also lost their lives. Dr. Weathers had undergone bilateral RK years before the expedition. He noted a decrease in vision, which started early during his ascent. Author Jon Krakauer recalls that “. . . as he was ascending from Camp Three to Camp Four, Beck later confessed to me, ‘my vision had gotten so bad that I couldn’t see more than a few feet.“ This decrease in vision forced Dr. Weathers to abandon his quest for the summit shortly after leaving Camp Four and nearly resulted in his death.
The refractive shift mentioned above is most likely due to low oxygen levels specifically, not necessarily low atmospheric pressures found atop high mountains. Furthermore, PRK and LASIK appear to be far safer procedures for individuals in the habit of frequenting very high altitudes; even so, standard precautions still apply to those who have had laser corrective surgery and whose activities take them to extreme heights:
[S]tudies at 4299 m (14,100 feet) on Pike’s Peak revealed that: (1) subjects who had undergone RK demonstrated a progressive hyperopic shift associated with flattened keratometry findings during a 72-hour exposure; (2) control eyes and eyes that had undergone laser refractive surgery (photorefractive keratectomy [PRK]) experienced no change in their refractive state; (3) peripheral corneal thickening was seen on pachymetry in all three groups; and (4) refraction, keratometry, and pachymetry all returned to baseline after return to sea level. There is strong evidence that the effect of altitude exposures on post-RK eyes is caused by hypoxia rather than by hypobarism and that breathing a normoxic inspired gas mix will not protect against the development of hypoxic corneal changes.
There is compelling evidence for myopic mountaineers that PRK instead of RK is their refractive surgical procedure of choice. Individuals who have undergone RK and plan to undertake an altitude exposure of 2744 m (9000 feet) or higher while mountaineering should bring multiple spectacles with increasing plus lens power.
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.
Finally, wilderness and mountain enthusiasts should be especially careful to protect their corneas from UV-induced corneal damage. Below are guidelines for choosing eye protection for the outdoors:
Snow blindness, or solar/ultraviolet keratitis is an excruciatingly painful state that comes from the sun burning the covering of your eye — the cornea. And it happens, very commonly if you don’t wear sunglasses, or if you don’t wear appropriate sunglasses in any bright light situation – especially easy to encounter at altitude.
Here are some guidelines to use when choosing a good trekking/mountaineering pair of sunglasses:
– 99-100% UV absorption
– Polycarbonate or CR-39 lens (lighter, more comfortable than glass)
– 5-10% visible light transmittance
– Large lenses that fit close to the face
– Wraparound or side shielded to prevent incidental light exposure
In the 1995 movie Braveheart, a young William Wallace grows up throwing stones with his left hand. After William’s family is killed, his uncle Argyle comes to Scotland to take him to continental Europe. Under Argyle’s expert tutelage, William somehow becomes ambidextrous and learns how to throw stones really well with his right hand:
Winters circulated among the wounded. One of them was Pvt. Albert Blithe.
“How’re you doing, Blithe? What’s the matter?”
“I can’t see, sir. I can’t see.”
“Take it easy, relax. You’ve got a ticket out of here, we’ll get you out of here in a hurry. You’ll be going back to England. You’ll be O.K. Relax,” Winters said, and started to move on.
Blithe began to get up. “Take it easy,” Winters told him. “Stay still.”
“I can see, I can see, sir! I can see you!”
Blithe got up and rejoined the company. “Never saw anything like it,” Winters said. “He was that scared he blacked out. Spooky. This kid just completely could not see, and all he needed was somebody to talk to him for a minute and calm him down.”
— from Stephen Ambrose, Band of Brothers
Breaking satirical news from http://www.theonion.com/article/nicoderm-introduces-new-nicotine-eye-patch-52243:
“These discreet and easy-to-use eye patches allow users to curb their cigarette cravings by delivering a steady flow of therapeutic nicotine directly into the bloodstream through the optic nerve,” said company spokesperson Caitlin Timmons, adding that the user simply removes the backing from the patch and applies the adhesive layer directly on their exposed cornea. “Individuals can choose to place the patch on their left eye or right eye, and the extended-release technology will reduce withdrawal symptoms for up to 72 hours. We recommend, however, that users don’t put on more than one at a time.”
The Cornea Society and The Figgs Eye Clinic do not recommend the use of this product.
My friend Amar P. and I (Dr. Chen) once had a brief discussion during a lab session in 10th grade Biology during which we very quickly concluded that the following was true.
The new year is upon us and so are resolutions to become healthier. Ocular health depends significantly on overall bodily health. Here are some thoughts from Ross Enamait on staying disciplined for the sake of improved health:
One of the biggest myths of all is that successful people are constantly motivated. The online world that we live in certainly perpetuates this false assumption. Social media only captures what a person wants you to see. As a result, certain people have created the illusion that they operate in a fairy tale land that’s devoid of bad days and bad moods.
The reality though is that no one lives in a constant state of motivation. We all experience ups and downs, and moments when we don’t feel like doing what needs to be done. Successful people don’t just work when they feel like working however. Instead, they are disciplined enough to get the job done regardless of their mood.
If you always wait to feel a certain way before you act, don’t expect to ever accomplish anything worthwhile. Too much time will be spent procrastinating as you sit around waiting for the perfect mood to arrive. Meanwhile, your successful competitors will be busy putting in the work whether they want to or not.
One of the keys to becoming more successful is recognizing the simple fact that life is tough. There is no such thing as a perfect time to work or start a new task. Therefore, rather than constantly seeking out motivation to begin or continue, your time would be better spent cultivating habits that will eventually lead towards enhanced productivity.
More from Ross:
The other night I was out running hills at a local park. As I finished one of my last sprints, a passerby walked over and jokingly said, “I wish I had your motivation.”
I had just finished sprinting a long hill so I wasn’t about to engage in a conversation. I smiled and waved in appreciation and began jogging back to the bottom of the hill.
While jogging down, I started to think about what the man said. All of a sudden, I found myself shaking my head. I wasn’t feeling motivated at all. It had been a long day, my sleep cycle was off from the holidays, and I surely would have felt better doing something else.
I had already run several sprints but my next one was the fastest of all. I sprinted to the top in hopes of seeing the man. Fortunately, he was already long gone. I probably would have sounded like a lunatic, but I wanted him to know that I wasn’t motivated at all. Motivation isn’t what puts one foot in front of the other. It’s discipline and work ethic that keeps me going.
In other words, just because I don’t feel like doing something doesn’t stop me from doing it anyway.
This year and beyond, forget your feelings and get disciplined. Your eyes — not to mention your whole body — will thank you.