Abstract
Purpose: :
To evaluate ocular phototoxicity in mountaineer guides which are characterized by an increased ultraviolet (UV) exposure linked to association of altitude and light reverberation on snow.
Methods: :
Two aged-matched groups of 96 guides working and 90 subjects living in plains, older than 50 years, replied to a very detailed questionnaire assessing altitude exposure, eye protective wear and nutritional or environmental factors since their diplomas. We performed slit lamp examination after pupil dilatation, retinal photography (Topcon) and crystalline lens density analysis (Oculyzer®, Alcon). Student t-test was used to compare the groups and logistic regression was performed to evaluate risk and protective factors in guides group.
Results: :
The two cities have same latitude and same sun exposure time. Guides mean age was 59.8years and 59.1years for control (p=0.39). Guides developed more chronic blepharitis (52.1% vs. 10.6%, p<0.01), pterygium (8.9% vs. 0%, p<0.01), pinguecula (58.3% vs. 21.7%, p<0.001). Their corneal break up time was shorter (4.5secs vs. 7secs, p<0.01). Guides presented more cortical cataract (p<0.01) and cataract surgery (p=0.01). Only 61.5% guides had normal ocular fundus vs. 81.1% in control group (p<0.01). They developed more drusenoids deposits (27.2% vs. 15.6%, p<0.01).Guides are 134.2 days per year in excursion during their carrier. They spend two-thirds of their time up to 3000m (65%) but when they are older than 50 years old, this activity decreases. Guides group analysis showed that exposure up to 3000m is risk factor to develop anterior cortical cataract (OR=1.16, p<0.01). Snow exposition increases maculopathy risk (OR=1.9, p<0.01). Questionnaire reveals discontinuous eye protection in medium altitude. Wearing ski mask reduces cataract (OR=0.5, p=0.037) and chronic blepharitis risk (OR=0.44, p<0.01). We find a protective effect on cataract formation when guides wear photo chromic glasses (OR=0.53, p=0.03) or hat (OR=0.46, p=0.04). Hat wearing is associated with a reduced risk of maculopathy (OR=0.4, p=0.02).
Conclusions: :
Guides develop more "ophthalmohelioses", ocular surface pathologies, anterior cortical lens opacities and drunenoids deposits. This data emphasizes the potential deleterious role of UVs and importance of light reverberation on snow. Protection must be the most complete possible with sunglasses and visor or hat.
Clinical Trial: :
https://eudract.ema.europa.eu 2010-A00647-32
Keywords: radiation damage: light/UV • clinical (human) or epidemiologic studies: risk factor assessment