Comparative evaluation of spectral transmittance of some welding glasses with ANSI Z87.1

Background: Welding emits harmful rays to the eyes. We evaluate and compare the UV, blue light and IR transmittance characteristics of some currently available welding safety protectors with ANSI Z87.1 criteria

Materials and Methods: Three type of welding safety protectors [three of each type] have been evaluated for spectral transmittance. One-sample T-test was performed to establish is there a statistically significant difference between the standard criteria and UV, blue and IR regions for the welding protectors [alpha=0.05]

Results: In ultraviolet [UV] [far and near] region, two types of the tested protectors [P1, P2] transmitted lower than the maximum allowable value specified in the standard [P<0.001]. In infrared [IR] spectrum only one type [P3] transmitted lower than the maximum allowable value specified in the standard [P<0.001]. In blue light region, all of the tested protectors transmitted lower than the maximum allowable value specified in the standard [P<0.001]

Conclusion: Although all of the tested glasses could meet some parts of the criteria, but none of them could meet the complete spectral transmittance requirements of ANSI Z87.1

Comparative evaluation of ultraviolet and visible light transmittance through prescriptive ophthalmic minus lenses

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