Short wavelengths filtering properties of sunglasses on the Canadian market: are we protected?

BACKGROUND

Exposure to solar radiation is a risk factor for multiple ocular pathologies. Ultraviolet (UV) radiation is involved in ocular diseases, including pterygium, ocular surface squamous neoplasia, and cataracts. High-energy visible light (HEV) is associated with age-related macular degeneration. Ocular protection against solar radiation seems essential to protect our eyes against the adverse effects of those harmful rays. Australia, New Zealand, Europe, and the United States are the only regions with mandatory standards for UV transmission for sunglasses. Adherence to Canadian standards by sunglasses manufacturers is not mandatory. In this study, we evaluated the UV and visible transmission of sunglasses in the Canadian market to test their compliance with Canadian standards.

METHODS

The transmittance of 207 pairs of sunglasses, divided in 3 categories according to their price range, was measured.

RESULTS

We show that close to 100% of the sunglasses tested respect the Canadian standards. The average HEV transmittance is around 10%, regardless the price range.

CONCLUSIONS

Our study demonstrated that even if following Canadian standards is optional, most sunglasses sold on the Canadian market follow national and international standards. We also found that sunglasses filter around 90% of HEV. With the recent findings on the potential effects of HEV in retinal pathologies, we can ask whether this filtering capacity is sufficient to protect eyes from harmful HEV light. More work needs to be done to determine acceptable HEV light transmission limits to the existing Canadian standards.