Lasik on top in ultimate test as daredevil climbers reach Mount Everest’s summit in 29,000ft hike
Sean Henahan in Burlington, Vermont
A DAREDEVIL 29,000ft hike to the summit of Mount Everest by a group of climbers who had all undergone Lasik surgery indicates that the procedure is safe for those pursuing adventure in the most extreme conditions.
Six climbers who underwent Lasik embark on 29,000ft hike to the summit of Mt Everest to examine the effects of hypobaric hypoxia on the cornea. The extraordinary climb was organised by ophthalmologists Geoff Tabin MD and Jason Dimming MD, who are also mountaineers. It is one of the few studies to look at the effects of hypobaric hypoxia on the cornea following Lasik and the only one examining the phenomenon at such altitude.Climbers preparing to scale Everest must undergo a lengthy period of acclimatisation at altitude, which includes spending at least one month at base camp altitude of 17,600ft, as well as repeated visits to higher camps at 20,000ft and above.
After acclimatisation, an attempt at the summit typically involves one night each at 20,000ft, 21,300ft, 24,000ft and 26,400ft, before the final push to 29,028ft. The mountaineering ophthalmologists monitored the visual acuity of 12 eyes of six climbers in the expedition. They obtained refractions at sea level before and after the climb and at the 17,600ft base camp before and after the climbers attempted the summit. They measured intraocular pressures at base camp using a portable tonometer and tracked the climbers’ subjective visual experiences at higher altitudes.
“Such extended time at and above 17,600ft provided an excellent model to study the effects of hypobaric hypoxia on the cornea after Lasik,” noted Dr Tabin, who in 1988 became the first ophthalmologist to reach the top of Everest. All the climbers in the expedition reached 26,000ft, with four who had bilateral Lasik reaching the summit. All used supplemental oxygen above 26,400ft. Five of the six climbers reported no subjective visual changes at up 26,400ft. One team member reported some blurring of vision above 16,000ft and two climbers reported similar problems above 27,000ft.
Three of the four who reached the summit reported no visual changes at the peak. One climber who reached the top reported some transient blurring. In each case the blurring improved with the subsequent descent and the use of lubricating drops. One climber who reached the summit reported a milky haze above 28,500ft but this disappeared on descent. He noted that the haziness was not accompanied by any myopic shift, an effect reported by a climber who climbed Aconcagua in Argentina after undergoing Lasik. Another climber turned around at 27,500ft when he developed a similar problem. He described his blurred vision as “like looking through waxed paper”. His vision returned to normal with 36 hours after descending to a lower altitude. All of the eyes returned to pre-climb visual acuity when the climbers returned to base camp. One adventurer, who had attempted Everest previously while wearing glasses, experienced decreased visual acuity (to 20/30) at the summit. He noted: “All in all, the advantage of not having glasses on Everest far outweighed any loss of visual acuity I had on the mountain.”
“Having Lasik was the best training for Everest I’ve ever done. The view from the top was the best I’ve ever had,” said another climber, Peter Athans MD, who reached the summit without difficulty. He had previously climbed to the summit of Everest six times, the most ascents by any non Sherpa climber, while wearing contact lenses. Dr Tabin suspects that the problems encountered by climbers who experienced difficulties were surface-related. Those who climbed to 27,000ft and above in particular may have experienced corneal oedema or corneal surface changes associated with dry eye induced by oxygen flow from the facemask. Even at the lower altitudes, he believes dry eye may have been associated with the visual changes.
“Dry eye may be biggest concern with Lasik in extreme conditions. Climbing at altitude is very dry and there can be a lot of wind. Any climber who has undergone Lasik needs to be evaluated for dry eye and to be maximally treated prior to going. They should also be advised to bring appropriate drops on the expedition,” Dr Tabin told EuroTimes. The amount of time elapsed after surgery did not appear to predict complications. The climbers had undergone Lasik anywhere from six weeks to three years prior to the expedition.
One of the climbers who had minor problems at the highest altitudes had undergone Lasik only three months prior to the hike, while the other underwent surgery three years previously. Similarly, two climbers who reached the summit without encountering any problems underwent surgeries at six weeks and three months earlier respectively. Refractive surgery got something of a bad name among climbers following an ill-fated expedition to Everest in 1996 during which several climbers died. One member of that trip, Beck Weathers MD, who had previously undergone radial keratotomy (RK), reported significant visual difficulties which he felt caused him to eventually lose both hands and nose to frostbite.
Dr Tabin believes the effects of the RK may have been greatly exaggerated by Dr Weathers. The hypoxia of altitude can lead to a swelling along the RK scars resulting in a flattening of the central cornea and a hyperopic refractive shift. “This can lead to a blurring of vision, but not the incapacitating blindness reported by Dr Weathers. Moreover, Dr Weathers was on relatively gentle ground which would have been easy to negotiate back down to camp by an experienced climber, even with loss of vision.
“Dr Weathers tragic injury was much more the result of an inexperienced climber going on a guided trip to a serious mountain rather than being caused by refractive surgery,” Dr Tabin said.
He also pointed out that several others who had undergone RK have reached the top of Everest with no reported visual problems, including one of the guides who saved Dr Weathers’ life. He did note that older people like Dr Weathers, who have less accommodative reserve, would be more affected at altitude by the post-RK hyperopic shift at altitude.
Dr Tabin adds that visual complications can also occur at high altitudes in those who have not undergone refractive surgery. Climbers have reported serious problems including severe corneal surface changes, corneal oedema, retinal haemorrhaging, retinal ischaemia and cerebral ischaemia which sometimes lead to blindness. Emmetropic patients have also reported transient changes in visual acuity at altitude. Dr Tabin, a self-described “climbing bum”, accomplished his own ascent of Everest while wearing contact lenses up to 26,400ft and spectacles for the remainder of the climb. This added to the difficulty of the task, he noted grimly.
“It was difficult to see through the contacts at those high altitudes because of the drying effect. You can imagine the hassle of keeping lenses clean under those conditions. It was also very difficult to keep my glasses clear in inclement weather.
“Fogging was a real problem which only worsened when we were using supplementary oxygen. This convinces me that refractive surgery is an attractive option for climbers,” Dr Tabin said.
He adds that he is still concerned about the potential effects of very high altitude on the cornea, noting that prospective studies at extreme altitudes would be necessary to clarify remaining questions.
In recent years there has been an increasing number of ‘tourists’ showing up at base camp. These are people who are simply not prepared for the physical and mental challenges presented by Everest. Dr Tabin does not appreciate this trend and recommends that only experienced climbers in top physical shape consider such an expedition.
Nonetheless, he believes the results of the current study can likely be extrapolated to those people who, although not ascending Everest, do enjoy skiing, climbing and other activities which can take them to altitudes above 10,000ft.
These active adventurers are from the same demographic that is the most interested in refractive surgery. These are people who will truly appreciate being free from contact lenses and spectacles with all the problems they bring in such conditions, he notes.
“Lasik is a fantastic thing for mountaineers. Climbers of peaks above 14,000ft will be glad to be free of the hassles that come with contacts and glasses. This becomes especially important in storm conditions. Those participating in skiing and other alpine sports would also appreciate the benefits of refractive surgery,” Dr Tabin explained.
He said he became interested in ophthalmology while in Nepal when he saw the “miracle of cataract surgery”. After completing his medical training, he worked in Nepal for a year where he ran an eye hospital. He returns to Nepal each year to teach cataract surgery as part of an endeavour he instituted called the Himalayan Cataract Project. Dr Tabin is the author of ‘Blind Corners’, a book describing some of his experience climbing and establishing eye surgery camps in Asia.
The Lasik on Mount Everest report appears in the Journal of Refractive Surgery (Dimming et al. 2003; 19:48-51).