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Fracture Resistance of Ophthalmic Lens-Frame Systems.

Authors
Goldsmith-W; Kors-K; Tomer-D; Mor-G; Yamada-R; Moline-D; Fields-J; Gonden-D
Source
NIOSH 1982 Nov :1-215
Link
NIOSHTIC No.
20023859
Abstract
The stated scope of the investigation was the determination of the response of a complete eyeglass system and a determination of the fracture potential of the lens under conditions of impact by solid objects. Concomitantly, the current FDA standards for prescription eyeglass lenses were to be examined from the viewpoint of utility in terms of engineering parameters of stress and strain. A coordinated theoretical and experimental approach was to be undertaken to predict the history of stress, strain and deformation and then verify the validity of the prognosis by experimental measurement, primarily within the range below the fracture limit. Various types of strikers and methods of projection were to be employed' against a series of simply-supported plano and prescription lenses and also against such lenses when emplaced in a frame mounted on an anthropometric headform. The effects of various mounting methods, including bevel configuration and eyewire grooving on the frangibility of the system was to be ascertained. Polymeric and multi-focal lenses were also to be examined if time permitted. The specific aims included the extension of an available finite element program dealing with the response of an axisymmetric body, simply supported at the edges, subjected to central normal impact to a general three-dimensional program so as to encompass all types of monofocal or bifocal prescription lenses struck at any arbitrary position. This phase was to be guided by concurrent experiments for a validation of the program. The subsequent effort was to be devoted to the recording of the effects of the impact of steel spheres on the entire lens/frame combination when positioned on a simulation of a human head. The effects of lens and frame configuration, type of bevel and presence of an eyewire, as well as the type of materials involved were to be considered. The magnitude of the forces transmitted to the face was also to be ascertained
Keywords
Ophthalmology; Optical-aids; Optics; Eye-glasses; Eye-protective-equipment; Force; Materials-testing; Anthropometry; Glass-products; Safety-glasses; Performance-capability
Contact
University of California, Berkeley, CA 94720
Publication Date
19821101
Document Type
Final Grant Report
Funding Amount
165231
Funding Type
Grant
Fiscal Year
1983
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-000766
NIOSH Division
OEP
Source Name
National Institute for Occupational Safety and Health
State
CA
Performing Organization
University of California, Berkeley, California
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