PMID: 9423905Jan 10, 1998Paper

Corneal topography bow-tie pattern: artifact of videokeratoscopy?

Journal of Cataract and Refractive Surgery
P R KellerP P van Saarloos

Abstract

To test the hypothesis that the bow-tie corneal topography pattern results from corneal asphericity in the presence of astigmatism. Astigmatic color-coded power maps using different shape factors were computer generated. Each simulation was based on the calculation of dioptric power at 20 points along each of 180 hemimeridia, for a total of 3600 points. The calculations were made independent of the capture or measurement of video-keratographs. These simulations were compared to power maps taken from clinical records. A shape factor of 1.00 resulted in a spherocylinder color-coded map with straight-edged sectors of power. The familiar bow-tie pattern was generated using an elliptical model with a shape factor of less than 1.00. This pattern was reversed by modeling the cornea as an oblate ellipsoid using a shape factor greater than 1.00. By simple alteration of the amount of corneal asphericity through manipulation of the shape factor, computer simulation showed that this surface characteristic is responsible for the bow-tie pattern observed in corneal topography power maps.

References

Mar 1, 1991·Archives of Ophthalmology·S E Wilson, S D Klyce
Feb 1, 1987·Archives of Ophthalmology·L J MaguireS D Klyce
Oct 1, 1984·American Journal of Optometry and Physiological Optics·P M KielyL G Carney
Jan 1, 1993·American Journal of Ophthalmology·R K MaloneyG O Waring
Jan 1, 1993·Ophthalmic & Physiological Optics : the Journal of the British College of Ophthalmic Opticians (Optometrists)·H Burek, W A Douthwaite
Nov 1, 1995·Optometry and Vision Science : Official Publication of the American Academy of Optometry·T O Salmon, D G Horner
Jul 1, 1996·The British Journal of Ophthalmology·Y S RabinowitzJ Elashoff
Feb 1, 1996·Optometry and Vision Science : Official Publication of the American Academy of Optometry·P R KellerP P van Saarloos

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Citations

Apr 26, 2002·Cornea·Tobias BuehrenD Robert Iskander
Jan 9, 2010·Journal français d'ophtalmologie·O TouzeauL Laroche

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