[Ocular phototoxicity and altitude among mountain guides]

This study aimed to evaluate ocular phototoxicity in mountaineer guides who experience overexposure to ultraviolet related to the altitude at which they work, as well as light reflection on snow.

Ninety-six guides and 90 controls living in plains, over 50 years old, underwent complete examinations. They responded to a questionnaire assessing altitude exposure and protective eyewear. We compared the two groups and performed a logistic regression within the guide group so as to identify risk and protective factors.

Guides develop more ocular surface diseases. They exhibit more anterior cortical cataract (P<0.01) and cataract surgery (P=0.01). Only 61.5% of guides had a normal ocular fundus versus 81.1% in control group (P<0.01). They exhibit more drusen (27.2% vs. 15.6%, P<0.01). Among the guide group, exposure at an altitude above 3000 m is risk factor for anterior cortical cataract (OR=1.16, P<0.01). Wearing ski masks (OR=0.50, P=0.04) or photochromic lenses (OR=0.53, P=0.03) reduces this risk. Exposure to snow increases the risk of maculopathy (OR=1.9, P<0.01). Wearing a hat reduces this risk (OR=0.40, P=0.02) and the risk of cataract formation (OR=0.46, P=0.04).

Guides develop more ocular surface diseases, anterior cortical lens opacities and drusen. These results underscore the potential deleterious role of ultraviolet radiation and the importance of light reflection on snow. The best ocular protection includes sunglasses and a hat with a visor or brim.