High Altitude and the Eye.

The purpose of this study was to review the available data on the effect of high altitude on the eyes. We carried out electronic literature search on www.pubmed.com for articles published through year 2011. The search terms included high altitude and the eye, high-altitude retinopathy, eye problems in the Himalayas, and eye diseases in Tibet. Other terms like visual functions, intraocular pressure, corneal thickness, tear function, and ocular motility, at high altitude, were searched separately and in combination. Data were retrieved from both prospective and retrospective studies published in the English language.High altitude has both short-term and long-term effects on the eyes. The short-term effects include high-altitude retinopathy, change in corneal thickness, and photokeratitis. Long-term effects include pterygium, cataract, and dry eye syndrome. High-altitude retinopathy of mild degree does not affect vision but has a predictive value for the development of high-altitude cerebral edema. Change in corneal thickness at altitude induces refractive changes in eyes with radial keratotomy and in eyes with LASIK. High altitude does not adversely affect visual acuity and contrast sensitivity; scotopic vision may be affected if supplemental oxygen is not used.