title: Equivalence between solar irradiance and solar simulators in aging tests of sunglasses.
abstract: BACKGROUND
  This work is part of a broader research that focuses on ocular health. Three outlines are the basis of the pyramid that comprehend the research as a whole: authors' previous work, which has provided the public to self-check their own sunglasses regarding the ultraviolet protection compatible to their category; Brazilian national survey in order to improve nationalization of sunglasses standards; and studies conducted on revisiting requirements of worldwide sunglasses standards, in which this work is inserted. It is still controversial on the literature the ultraviolet (UV) radiation effects on the ocular media, but the World Health Organization has established safe limits on the exposure of eyes to UV radiation based on the studies reported in literature. Sunglasses play an important role in providing safety, and their lenses should provide adequate UV filters. Regarding UV protection for ocular media, the resistance-to-irradiance test for sunglasses under many national standards requires irradiating lenses for 50 uninterrupted hours with a 450 W solar simulator. This artificial aging test may provide a corresponding evaluation of exposure to the sun.
  
  
  METHODS
  Calculating the direct and diffuse solar irradiance at a vertical surface and the corresponding radiant exposure for the entire year, we compare the latter with the 50-h radiant exposure of a 450 W xenon arc lamp from a solar simulator required by national standards.
  
  
  RESULTS
  Our calculations indicate that this stress test is ineffective in its present form.
  
  
  CONCLUSIONS
  We provide evidence of the need to re-evaluate the parameters of the tests to establish appropriate safe limits for UV irradiance.
  
  
  CONCLUSIONS
  This work is potentially significant for scientists and legislators in the field of sunglasses standards to improve the requirements of sunglasses quality and safety.
authors: Electrical Engineering Department, Engineering School of São Carlos, University of São Paulo, Av. Trabalhador Sãocarlense 400, São Carlos, SP, 13566-590, Brazil.
authors: Mauro
authors: M
authors: Masili
authors: Electrical Engineering Department, Engineering School of São Carlos, University of São Paulo, Av. Trabalhador Sãocarlense 400, São Carlos, SP, 13566-590, Brazil. lilianeventura@usp.br.
authors: Liliane
authors: http://orcid.org/0000-0002-5292-6687
authors: L
authors: Ventura
mesh_terms: D004058:Diffusion; D005123:Eye / Q000528:radiation effects; D005139:Eyeglasses / Q000592:standards; D008422:Materials Testing; D011835:Radiation Protection; D012449:Safety; D013472:Sunlight; D013997:Time Factors
keywords: Solar resistance testing for sunglasses; Sunglasses aging test; Sunglasses standards; UV ocular protection; Ultraviolet A and B protection for sunglasses