They are back in the highest city in the world. For the fifth consecutive year, Rhône-Alpes researchers and practitioners have settled in La Rinconada, a Peruvian town of 50,000 inhabitants as part of “Expedition 5,300”. They will continue their work on the consequences of very high altitudes on the human body, focusing in particular this year on ophthalmic issues.
At an altitude of 5,300 meters on this Peruvian Altiplano dominated by the glaciers of the Andes Cordillera, the sun is the main risk for the eyes. “There are many more ultraviolet rays which can be dangerous for the eyes, explains Aymeric Paillisser, ophthalmologist who usually practices at the Grenoble University Hospital. “This can increase cataracts. But above all, we have a frequency of almost 100% of pterygions, that is to say that to protect against ultraviolet rays, the sclera, the white of the eye, will gradually cover the cornea , which is the transparent part. This will create astigmatism, ie it will lower the vision.”
For this doctor, as for the rest of the team, the objectives of “Expedition 5300” are twofold: to study the physical adaptation of these inhabitants to these very high altitudes, but also to provide care for those who suffer from this permanent exposure to an environment where the main element is the crying lack of oxygen. This is explained by Samuel Vergès, head of this mission and research director at INSERM: “The 50,000 inhabitants of La Rinconada have quantities of red blood cells, the cells that carry oxygen in the blood. But this very large quantity of red blood cells makes the blood very viscous, almost pasty. It is therefore difficult to circulate in the vessels, the heart forces.”
“Vital organs, such as the brain, are poorly irrigated and this is what develops what is called chronic mountain sickness.”
Samuel Verges,at franceinfo
Samuel Vergès and his team did not escape the consequences of this hostile environment, to the point of becoming objects of research themselves. “One of the challenges of this year’s mission is to carry out measurements on our team of researchers, from the plains, to see how far we are getting in terms of adaptation, describes the researcher. What we can say is that after a few weeks of acclimatization, we are very, very far from what the inhabitants have been able to develop as adaptation mechanisms for thousands of years.
This lack of adaptation results in rapid physical wear and tear which obliges the team to limit its work on site to one month, before continuing research in the laboratory, at more lenient altitudes.