Evaluation of intraocular pressure and corneal thickness in individuals at high altitude area (10000 ft above sea level).

Background. At high altitude changes in corneal thickness and intraocular pressure (IOP) has been a subject of investigation for decades. The mechanism of action of these changes is still unknown. Extensive research is carried out to know effect of hypoxia on humans at high altitude. Corneal thickness and intraocular pressure are important parameter in ophthalmology with both diagnostic and therapeutic implications. We studied the corneal thickness and intraocular pressure in highlanders and compared the same with lowlanders. Methods. This observational study included two groups, each consisting of 500 individuals residing at high altitude (more than 10,000 ft above sea level). Three measurements of intraocular pressure of both eyes in each group were noted with Goldmann applanation tonometer and mean of the three readings was taken. Central Corneal Thickness (CCT) was measured by ultra sound pachymetry. The parameters of two groups were compared statistically. Results. There was a statistically significant difference between corneal thicknesses of the two groups studied, however no overall statistically significant difference in intraocular pressure of both these groups was found. Conclusion. The highlanders have a thinner cornea as compared to lowlanders. The IOP is significantly higher in the highlander males as compared to lowlander males. However, the mean IOP is comparable between the overall population of the high altitude and that of low altitude.