EVALUATION OF SUNGLASSES PERFORMANCE TO FILTER HARMFUL SHORT WAVELENGTH LIGHTS

Solar spectrum is composed of different wavelengths that some of them may lead to various ocular diseases. The aim of this study was to investigate the effectiveness of sunglasses in filtering harmful light.

In this cross-sectional study, 56 pairs (112 lenses) of branded sunglasses randomly collected from different importing companies. A spectrophotometer was used to measure blue light transmission. For statistical analysis, non-parametric Mann-Whitney and Kruskal-Wallis tests were used. A P ≤ 0.05 was considered statistically significant.

The mean UVA and UVB transmission of the sunglasses were 0.16±1.21% and 0.01±0.06 %, respectively. The mean blue light transmission of the sunglasses was 10.03 ± 3.91 %. The effect of different colors on the blue light transmission was significant (P≤0.001). Polarization and visible light transmission of the sunglasses had no significant effect on blue light transmission (P=0.3).

The effectiveness of available sunglasses to filter hazardous light was acceptable, and brown colored sunglasses was the best option to filter of the blue light.