Prismatic Effects of Spherical Ophthalmic Lenses
Exact prismatic effects were calculated for stock spectacle lenses (-6 D to +10 D) and trial refracting set lenses (-10 D to +10 D) using a range of visual field eccentricities on the 0.30 m Goldmann perimeter, and on the 1- and 2-m tangent screens. Slightly larger prismatic effects were found for the tangent screens than the perimeter, but the difference in results for the two tangent screen distances was negligible. For low power ophthalmic lenses (-2 D to +2 D), the prismatic effects were smaller than the variation in apparent target eccentricity caused by variation in patient fixation distance. Paraxial estimates of prismatic effects using both thick and thin lens theory were calculated, but found to become more inaccurate as target eccentricity increased. Data are presented which can be used by clinicians to predict the alteration in the size of kinetic perimetric isopters when ophthalmic lenses are used to correct patient defocus resulting from ametropia or presbyopia.
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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:||prismatic effect, ophthalmic lenses, visual field, perimetry, pupil aberration|
|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 1980 Lippincott Williams & Wilkins|
|Deposited On:||17 Aug 2006|
|Last Modified:||15 Jan 2009 17:08|
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