Comparison of Automated and Partial Coherence Keratometry and Resulting Choice of Toric IOL
- 1 April 2013
- journal article
- research article
- Published by Ovid Technologies (Wolters Kluwer Health) in Optometry and Vision Science
- Vol. 90 (4), 385-391
- https://doi.org/10.1097/opx.0b013e318287345b
Abstract
Consistent astigmatism correction with implantation of a toric intraocular lens (IOL) requires accurate preoperative keratometry. This article compares corneal astigmatism determined by an autokeratometer (Topcon KR-7100) and a partial coherence interferometry keratometer (IOLMaster 500) and considers if any discrepancy ultimately alters in final cylindrical power of the toric IOL for implantation. Keratometry of 235 eyes was performed using both instruments. Corneal astigmatism was transformed into vector components J0 and J45 and cylindrical power at the IOL plane calculated. Comparisons were made using paired t test and correlation and Bland-Altman analyses. Although interinstrument differences for J0 (p = 0.013), J45 (p = 0.012), and toric IOL cylindrical power (p < 0.001) were statistically significant, a high correlation for these (R = 0.96, 0.90, and 0.90, respectively) was observed. IOLMaster tended to overestimate corneal astigmatism by 0.13 (±0.31) diopters and toric IOL cylinder by 0.11 (±0.18) diopters. Difference in calculated toric IOL cylindrical power correlated poorly with corneal curvature (R = 0.007) and astigmatism (R = -0.004). The two keratometers were generally concordant in measuring corneal astigmatism. However, the resultant choice of toric IOL cylinder power differed appreciably in 40% of eyes examined. Therefore, postoperative visual outcome with toric IOL implantation may be optimized by a thorough analysis of biometry data before IOL selection, paying special attention to any difference in corneal astigmatism as measured by more than one instrument.This publication has 36 references indexed in Scilit:
- Aiming for emmetropia after cataract surgery: Swedish National Cataract Register studyJournal of Cataract & Refractive Surgery, 2012
- High prevalence of astigmatism in the 40‐ to 64‐year‐old population of Shahroud, IranClinical & Experimental Ophthalmology, 2011
- Factors related to the degree of success in achieving target refraction in cataract surgeryJournal of Cataract & Refractive Surgery, 2008
- Prevalence of Refractive Error in the United States, 1999-2004JAMA Ophthalmology, 2008
- Improved accuracy of intraocular lens power calculation with the Zeiss IOLMasterActa Ophthalmologica Scandinavica, 2006
- Limbal relaxing incisions versus on-axis incisions to reduce corneal astigmatism at the time of cataract surgeryJournal of Cataract & Refractive Surgery, 2005
- Correction of pre-existing astigmatism during cataract surgery: comparison between the effects of opposite clear corneal incisions and a single clear corneal incisionAlbrecht von Graefes Archiv für Ophthalmologie, 2004
- Improved prediction of intraocular lens power using partial coherence interferometryJournal of Cataract & Refractive Surgery, 2001
- Refractive Errors Induced by Displacement of Intraocular Lenses within the Pseudophakic EyeOptometry and Vision Science, 1989
- Biometry of 7,500 Cataractous EyesAmerican Journal of Ophthalmology, 1980