Estimation of true corneal power after keratorefractive surgery in eyes requiring cataract surgery: BESSt formula
- 1 December 2006
- journal article
- Published by Ovid Technologies (Wolters Kluwer Health) in Journal of Cataract & Refractive Surgery
- Vol. 32 (12), 2004-2014
- https://doi.org/10.1016/j.jcrs.2006.08.037
Abstract
To describe a new formula, BESSt, to estimate true corneal power after keratorefractive surgery in eyes requiring cataract surgery.Moorfields Eye Hospital, London, United Kingdom.The BESSt formula, based on the Gaussian optics formula, was developed using data from 143 eyes that had keratorefractive surgery. The formula takes into account anterior and posterior corneal radii and pachymetry (Pentacam, Oculus) and does not require pre-keratorefractive surgery information. A software program was developed (BESSt Corneal Power Calculator), and corneal power was calculated in 13 eyes that had keratorefractive surgery and required cataract surgery.In the eyes having phacoemulsification, target refractions calculated with the BESSt formula were statistically significantly closer to the postoperative manifest refraction (mean deviation 0.08 diopters [D] +/- 0.62 [SD]) than those calculated with other methods as follows: history technique (-0.07 +/- 1.92 D; P = .05); history technique with double-K adjustment (0.13 +/- 2.39 D; P = .05); Holladay 2 with K-values estimated with the contact lens method (-0.76 +/- 1.36 D; P = .03); Holladay 2 with K-values from Atlas topographer (Humphrey) (-0.55 +/- 0.61 D; P<.01). Using the BESSt formula, 46% of eyes were within +/-0.50 D of the intended refraction and 100% were within +/-1.00 D.The BESSt formula was statistically significantly more accurate than the other techniques tested. Thus, it could significantly improve intraocular lens power calculation accuracy after keratorefractive surgery, especially when pre-refractive surgery data are unavailable.Keywords
This publication has 17 references indexed in Scilit:
- Nomogram-Based Intraocular Lens Power Adjustment after Myopic Photorefractive Keratectomy and LASIK: A New ApproachOphthalmology, 2005
- Reliability of a new correcting factor in calculating intraocular lens power after refractive corneal surgeryJournal of Cataract & Refractive Surgery, 2005
- Intraocular lens calculations after refractive surgeryJournal of Cataract & Refractive Surgery, 2005
- Refractive Index Change in Bovine and Human Corneal Stroma before and after LASIK: A Study of Untreated and Re-treated Corneas Implicating Stromal HydrationInvestigative Ophthalmology & Visual Science, 2004
- Intraocular lens power calculation after corneal refractive surgery: Double-K methodJournal of Cataract & Refractive Surgery, 2003
- Intraocular lens power calculation after refractive surgeryJournal of Cataract & Refractive Surgery, 2003
- Measuring corneal power for intraocular lens power calculation after refractive surgeryJournal of Cataract & Refractive Surgery, 2002
- Refractive Complications of Cataract Surgery After Radial KeratotomyAmerican Journal of Ophthalmology, 1989
- Improving the Predictability of Intraocular Lens Power CalculationsAmerican Journal of Ophthalmology, 1986
- On the calculation of power from curvature of the cornea.British Journal of Ophthalmology, 1986