On the Description of Zonal Aspheric Surfaces
It is shown that, in general for a rotationally symmetric surface, the sagittal curvature is a function of the first derivative and tangential curvature is a function of the first and second derivatives of the surface equation. Smith and Atchison developed an "off-set" model for zonal aspheric surfaces with continuous gradients (or first derivatives) at the boundaries. This model predicts continuous sagittal power errors but discontinuities in tangential power errors. However, measurements on commercially available zonal lenses by Atchison and Smith showed that both sagittal and tangential power errors were continuous across zone boundaries. Thus it is likely that the off-set model is incorrect. Zonal aspheric surfaces are more likely to be made according to a "co-axial" model which is described.
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|Item Type:||Journal Article|
|Additional Information:||The contents of this journal can be freely accessed online via the journal's web page (see link) 12 months after publication. For more information, please refer to the journal’s website (see link) or contact the author. Author contact details: firstname.lastname@example.org|
|Keywords:||aspheric lens, zonal aspherics, continuous aspherics|
|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|
Current > Institutes > Institute of Health and Biomedical Innovation
|Copyright Owner:||Copyright 1986 Lippincott Williams & Wilkins|
|Deposited On:||17 Aug 2006|
|Last Modified:||15 Jan 2009 17:08|
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