Prism in pairs of progressive power lenses
The off-axis prismatic effects (prism) of five types of progressive power lenses were measured on a modified vertometer. The lens types assessed were the Essilor (Hoya) Varilux II, the American Optical Truvision Omni, the SOLA Graduate, the Rodenstock Progressiv R, and Zeiss Gradal HS. Conventional flat top bifocal lenses were also assessed. Progressive power lenses have smooth changes of prismatic effects, free of sharp "jumps" associated with bifocals. Differential prism of progressive lens pairs matched for power mainly result from a failure of some manufacturers to design for individual right and left lenses. This failure can produce up to 1.0Δ vertical and horizontal differential prism. We recommend that reduction of differential prismatic effects be carefully considered in future progressive lens design.
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|Item Type:||Journal Article|
|Additional Information:||The contents of this journal from 1998 to 2005 can be freely accessed online via the journal’s web page (see link). For more information or for a copy of this article contact: David A. Atchison email@example.com|
|Keywords:||bifocals, prism, prismatic effect, progressive power lenses, spectacle lenses|
|Subjects:||Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)|
|Divisions:||Current > QUT Faculties and Divisions > Faculty of Health|
|Copyright Owner:||Copyright 1989 Optometrists Association Australia|
|Deposited On:||15 Aug 2006|
|Last Modified:||15 Jan 2009 07:09|
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