A previous meta-analysis revealed that chronic occupational natural ultraviolet light exposure was a borderline non-significant risk factor for UM, whereas geographic latitude and outdoor leisure UV exposure were not significant ( 35 ).
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The average choroidal melanoma thickness at diagnosis has exhibited a decreasing trend from 5.5 mm in the 1970s, to 4.5 mm in the 1990s, to 4 mm in more recent times ( 43 ) This demonstrates the efforts in improving the early diagnosis of the tumor.