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PurposeCalculation of intraocular lens (IOL) power for implantation during cataract surgery depends on ocular biometric measurements. The aim of this study was to characterise the normal range of intra- and interindividual variation in axial length (AL) and corneal power (K) when IOLMaster measurements were possible and to derive recommendations as to which outlying measurements merit verification before acceptance.MethodsThe Medisoft electronic patient database contains prospectively collected data conforming to the United Kingdom (UK) Cataract National Dataset on 55 567 cataract operations. From this AL and Kinformation on the 32 556 eyes (14 016 paired) of patients older than 25 years, without corneal pathology, history of intraocular surgery and who had all biometric measurements taken with the Zeiss IOLMaster (Carl Zeiss Meditec) were extracted. R 2.8.1 (R Foundation for Statistical Computing) was used for statistical analysis.ResultsMean age was 76.4 years and 62.0% were female. Mean (95% confidence interval) values for AL, mean Kand corneal astigmatism were 23.40 (21.27–26.59) mm, 43.90 (40.94–47.01) D and 1.04 (<2.50) D. Nearly all astigmatism was either with or against the rule. Differences between paired eyes were not statistically significant. 95% individuals had asymmetry of AL and mean K<0.70 mm and 0.92 D, respectively.ConclusionsOn the basis of approximation of the 95% CI above, it is suggested that AL, mean Kand keratometric astigmatism measurements outside the ranges 21.30–26.60 mm, 41.00–47.00 D and >2.50 D, respectively, and intraindividual asymmetry of AL >0.70 mm or mean K>0.90 D should be verified before acceptance. [ABSTRACT FROM AUTHOR]

PurposeTo assess the reliability of IOLMaster in axial length (AL) measurement in phakic silicone oil-filled vspseudophakic saline-filled eyes.MethodsTen eyes of 10 patients, vitrectomized with silicone oil tamponade and scleral buckled with significant lens opacity were enrolled. Optical biometry with IOLMaster (Carl Zeiss Meditec AG, Germany) was performed 1 day before and 1 week after silicone oil removal and phacoemulsification with artificial intraocular lens (IOL) implantation in order to assess changes in AL measurements.ResultsMean AL was 26.16±1.23 mm (range 24.64–28.8 mm) and 26.27±1.46 mm (range 25.26–29.6 mm), respectively, the day before and 1 week after silicone oil removal and cataract surgery, and the difference was not statistically significant (P=0.2).ConclusionsPresence vsabsence of silicone oil tamponade as well as phakic vspseudophaphakic status in buckled and vitrectomized eyes did not influence the AL measurement by means of no-contact optical biometry, suggesting that such eyes might be candidate for silicone oil removal and cataract surgery at one time.Eye (2007) 21, 909–911; doi:10.1038/sj.eye.6702452; published online 28 July 2006 [ABSTRACT FROM AUTHOR]