RESUMO
Wearing spectacles is the most common approach in correcting the refractive errors worldwide. Due to harmful effects of overexposure to solar ultraviolet radiations, the usage of multi-layer coatings in ophthalmic lenses has recently been increased. These lenses can reduce the reflections and hence increase the transmission of visible light; they can also decrease the transmission of ultraviolet rays. This study aims to compare the transmission of ultraviolet [A and B] and visible rays through coated and uncoated prescriptive ophthalmic plastic lenses. In this study, 39 minus non-photochromic multi-coated white plastic single-vision lenses; 9 similar lenses but without any coatings were assessed by spectral transmittancemeter for evaluation of the transmission of visible and ultraviolet rays. The transmission of visible light was 97.9% +/- 1.07% for coated lenses and 93.5% +/- 0.54% for lenses without coating. Ultraviolet-A transmission was 12.15% +/- 8.02% for coated lenses compared to 66.27% +/- 23.92% in lenses without coating. The transmission of ultraviolet-B rays was 1.21% +/- 0.4% and 23.0% +/- 15.97% for lenses with and without coatings, respectively. The transmission of visible light was significantly higher in multi-coated lenses compared to uncoated samples; whereas the transmissions of ultraviolet rays in multi-coated lenses were significantly lower than uncoated ones. Therefore, it is recommended that, except for particular cases, prescribed lenses be equipped with this multilayer coating