Comparison of two optical biometric devices for intraocular lens calculation

BackgroundModern cataract surgery not only consists of aminimally invasive lens extraction but also of the implantation of asuitable intraocular lens.ObjectiveThe aim of this prospective trial was acomparison of the predicted refractive error of two optical biometers, the IOLMaster500 and LenStar LS 900 for intraocular lens power calculation in cataract surgery.Material and methodsThis was aprospective, analytical, comparative, non-masked study. A total of 86 eyes of 86patients were examined and measured with both instruments before and after uneventful cataract surgery. Primary outcome measures were the differences of the predicted refractive error of both instruments. The predicted refractive error was calculated with different formulas. The results were compared to each other, to the desired target refraction as well as to the postoperative spherical equivalent.ResultsThe mean differences in predicted refractive error of both instruments varied between 0.9 +/- 0.19 (standard deviation) diopters(D) and 0.18 +/- 0.30D depending on the chosen formula. The IOLMaster500 predicted less difference to the desired target refraction as well as to the spherical equivalent than the LenStarLS900 with nearly all formulas.ConclusionBoth devices generated reproducible exact data with only asmall deviation from the desired target refraction and from the postoperative spherical equivalent. There were statistically significant differences based on the chosen a-constants as well as the utilized measurement methods of both instruments.