PMID: 9530595Apr 8, 1998Paper

Keratometric index, videokeratography, and refractive surgery

Journal of Cataract and Refractive Surgery
P G GobbiR Brancato

Abstract

To clarify the confusion resulting from the use of slightly different refractive indices in calculations related to optical modeling of the cornea for refractive surgery, corneal diagnostics, and cataract surgery. Scientific Institute H.S. Raffaele, Milan, Italy. The cornea is represented as a centered optical system composed by 1, 2, or 3 spherical interfaces, in progression of modeling accuracy. Optical analysis is performed with the usual formulas of paraxial geometrical optics as well as with ray tracing. Simple models are also provided for corneas having both incisional and photoablative refractive surgery. Values of geometrical parameters are taken from the Gullstrand eye model. Using the keratometric index of refraction of 1.3375 is validated for estimating optical power differences on untreated corneas or after incisional keratotomy. It is not as accurate in assigning absolute values of dioptric power, where the value 1.3315 is more appropriate. For photorefractive keratectomy (PRK), however, the proper stromal index of refraction, 1.376, must be used for ablation calculations and dioptric change estimates. Videokeratographic instruments should include three distinct values of refraction index (1.3375, 1.376, and 1.3315...Continue Reading

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Citations

Nov 27, 2007·Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft·C-A LackerbauerA Kollias
Jan 3, 2001·Journal of Cataract and Refractive Surgery·R PeterI Schipper
Apr 17, 2002·Journal of Cataract and Refractive Surgery·Shuan Chen, Fung-Rong Hu
Aug 6, 2003·Journal of Cataract and Refractive Surgery·Wolfgang Haigis
Aug 6, 2003·Journal of Cataract and Refractive Surgery·Carlos ArgentoDaniel Badoza
Mar 20, 2004·Journal of Cataract and Refractive Surgery·Nicola RosaAntonio Romano
Dec 13, 2003·Journal of Cataract and Refractive Surgery·Jaime Aramberri
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Jun 19, 2013·Optometry and Vision Science : Official Publication of the American Academy of Optometry·Vicente J CampsVerónica Mateo
May 31, 2014·Journal of Cataract and Refractive Surgery·Giacomo SaviniKenneth J Hoffer
Jul 21, 2012·Journal of Cataract and Refractive Surgery·David P PiñeroPedro Ruiz-Fortes
Aug 4, 2010·Journal of Refractive Surgery·Maolong TangDavid Huang
Nov 4, 2006·Journal of Cataract and Refractive Surgery·Maolong TangDavid Huang
May 16, 2006·Journal of Cataract and Refractive Surgery·Pier Giorgio GobbiRosario Brancato
Jan 1, 2012·Saudi Journal of Ophthalmology : Official Journal of the Saudi Ophthalmological Society·Maolong TangDavid Huang
Feb 14, 2006·Journal of Cataract and Refractive Surgery·Charlotte E JoslinElmer Y Tu
Oct 18, 2016·Current Opinion in Ophthalmology·Claudia E Perez-Straziota, J Bradley Randleman
Dec 2, 2006·Journal of Cataract and Refractive Surgery·Edmondo BorasioGuy T Smith
Jun 25, 2005·Journal of Cataract and Refractive Surgery·Nicola RosaAntonio Romano
Aug 10, 2010·Journal of Cataract and Refractive Surgery·Giacomo SaviniPiero Barboni
Nov 14, 2020·Graefe's Archive for Clinical and Experimental Ophthalmology = Albrecht Von Graefes Archiv Für Klinische Und Experimentelle Ophthalmologie·Raphael DienerMaged Alnawaiseh
May 27, 2008·Journal of Refractive Surgery·Han Bor Fam, Kooi Ling Lim
Jul 22, 2021·Graefe's Archive for Clinical and Experimental Ophthalmology = Albrecht Von Graefes Archiv Für Klinische Und Experimentelle Ophthalmologie·Jungah HuhHyo Myung Kim

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