title: Theoretical model for design and analysis of protectional eyewear.
abstract: BACKGROUND
  Protectional eyewear has to fulfill both mechanical and optical stress tests. To pass those optical tests the surfaces of safety spectacles have to be optimized to minimize optical aberrations.
  
  
  METHODS
  Starting with the surface data of three measured safety spectacles, a theoretical spectacle model (four spherical surfaces) is recalculated first and then optimized while keeping the front surface unchanged. Next to spherical power, astigmatic power and prism imbalance we used the wavefront error (five different viewing directions) to simulate the optical performance and to optimize the safety spectacle geometries.
  
  
  RESULTS
  All surfaces were spherical (maximum global deviation 'peak-to-valley' between the measured surface and the best-fit sphere: 0.132mm). Except the spherical power of the model Axcont (-0.07m(-1)) all simulated optical performance before optimization was better than the limits defined by standards. The optimization reduced the wavefront error by 1% to 0.150 λ (Windor/Infield), by 63% to 0.194 λ (Axcont/Bolle) and by 55% to 0.199 λ (2720/3M) without dropping below the measured thickness.
  
  
  CONCLUSIONS
  The simulated optical performance of spectacle designs could be improved when using a smart optimization. A good optical design counteracts degradation by parameter variation throughout the manufacturing process.
authors: Experimental Ophthalmology, Saarland University, Germany. benedikt.zelzer@uks.eu
authors: B
authors: B
authors: Zelzer
authors: A
authors: A
authors: Speck
authors: A
authors: A
authors: Langenbucher
authors: T
authors: T
authors: Eppig
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005135:Eye Protective Devices; D005139:Eyeglasses; D008962:Models, Theoretical