[Comparison of IOL-Master 500 vs. Lenstar LS900 concerning the calculation of target refraction: A retrospective analysis].
BACKGROUND
The choice of a suitable intraocular lens (IOL) and the calculation of postoperative refractive error is one of the most intriguing challenges of modern cataract surgery. This clinical trial compared the accuracy of two laser-assisted optical biometers, the IOL-Master 500 (Carl Zeiss Meditec, Jena, Germany) and the Lenstar LS900 (Haag-Streit, Bern, Switzerland) without taking the postoperative results into consideration.


METHODS
Artificial lenses (Alcon Pharma) for 114 eyes of 67 patients were measured using both biometric instruments. The deviation of the presumed refractive error from the desired preoperative refractive target was calculated with different formulae (i.e. SRK/T, HofferQ, Haigis and SRKII) based on the intraoperatively chosen IOL. The differences between both instruments were compared using Student's t-test.


RESULTS
Using the SRKII formula a mean difference between the IOL-Master and the Lenstar of 0.07 D (p = 0.002) was calculated for 95 eyes, SRK/T used on 47 eyes showed a difference of 0.04 D (p = 0.27), HofferQ measured 0.09 D (p = 0.0001) between both instruments for 88 eyes and the Haigis formula also showed a mean difference of 0.09 D (p = 0.001) based on the calculations of 106 eyes.


CONCLUSIONS
Both instruments gave reproducible and accurate results with only a small deviation from the desired target refraction and can therefore be considered as comparable for the calculation of IOLs. Statistically significant differences in the results were found when using the SRKII, HofferQ and Haigis formulae but these were too low to have any influence on the choice of IOL to be implanted.
Department of Ophthalmology, Innsbruck Medical University, Anichstr. 35, 6020, Innsbruck, Österreich, martin.stattin@uki.at.
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Stattin
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Zehetner
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NE
Bechrakis
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L
Speicher
D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D007910:Lenses, Intraocular; D017755:Prosthesis Fitting / Q000295:instrumentation*; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000175:diagnosis*; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity