An improved universal theoretical formula for intraocular lens power prediction
- 1 November 1993
- journal article
- research article
- Published by Ovid Technologies (Wolters Kluwer Health) in Journal of Cataract & Refractive Surgery
- Vol. 19 (6), 713-720
- https://doi.org/10.1016/s0886-3350(13)80339-2
Abstract
Although available empirically derived and theoretical formulas perform adequately for eyes of average axial length, both have been shown to be deficient for eyes that have unusually short and long axial lengths. I developed a formula based on a theoretical model eye in which anterior chamber depth is related to axial length and keratometry. A relationship between the A-constant and a "lens factor" is also used to determine anterior chamber depth. The location of the intraocular lens' principle planes of refraction is retained as a relevant variable in the formula, and the user need not know the material and construction of the lens and or its constant. I compared the new formula with the SRK II, Holladay, and SRK/T formulas in a group of 100 unselected patients and in selected subgroups of patients with average, short, and long axial lengths. The new formula was significantly more accurate than the other third-generation formulas and maintained its accuracy in the subgroups. The formula can be described as universal because it can be used for different lens styles and for eyes with short, medium, and long axial lengths.Keywords
This publication has 13 references indexed in Scilit:
- Development of the SRK/T intraocular lens implant power calculation formulaJournal of Cataract & Refractive Surgery, 1990
- Theoretical versus SRK I and SRK II calculation of intraocular lens powerJournal of Cataract & Refractive Surgery, 1990
- Biometry of the posterior lens capsule: A new method to predict pseudophakic anterior chamber depthJournal of Cataract & Refractive Surgery, 1990
- Corneal asphericity and refractive errorOphthalmic and Physiological Optics, 1989
- Comparison of the SRK II™ formula and other second generation formulasJournal of Cataract & Refractive Surgery, 1988
- A three-part system for refining intraocular lens power calculationsJournal of Cataract & Refractive Surgery, 1988
- Intraocular lens calculation formulas for new intraocular lens implantsJournal of Cataract & Refractive Surgery, 1987
- Prediction of intraocular lens position after cataract extractionJournal of Cataract & Refractive Surgery, 1986
- Improvement of intraocular lens power calculation using empirical dataAmerican Intra-Ocular Implant Society Journal, 1980
- A new intraocular lens calculation formulaAmerican Intra-Ocular Implant Society Journal, 1980