Comparison of intraocular lens power calculation formulas in pediatric surgery

Purpose: Comparison of theaccuracy ofintraocular lens powercalculationformulas(SRK II, SRK/T, Holladay 1, Hoffer Q and Barrett II Universal) in pediatricpopulation. Methods: : Inthisprospectivestudy, weincluded 70 eyes of 70 patientsbetweenages of 3-15 who had underwentcataractsurgerywith IOL implantation. Measurements of patientparameterslikeaxiallenght, keratometer, anteriorchamberdepth, horizontalcornealdiameterandcentralcornealthicknessweredonewithAlScan (Nidek) optical biometer. Implanted IOL powerwascalculatedusing Barrett II Universal formulabecause of thepreviouslysuccesfulresults in adultpopulation. Only 1 eye of thepatientswasincluded in ourstudy. Patientswho had anycomplicationduringoraftersurgerywereexcludedfromthestudy. Postoperativerefraction (sphericalequivalent) wastaken at 1 monthafterthesurgery. Wefurtherdividedthepatientsintosubgroupsaccordingtoaxiallengthandkeratometryvalues. Weusedmeanabsolutepredictiveerror (APE) of theformulasforstatisticalanalysis. Results: Thelowest APE wasachievedwith Barrett II formula (0.64±0.73D) andthehighestwith Haigis formula (1.06±0.84D)in thewholestudypopulation(p<0.01).APE values of AXL ≤22mm patientgroupwerelowestwithHolladay 1 (0.79±0.71D) andhighestwithHaigis (1.44±0.92 D), in AXL>22mmpatientgrouplowest APE waswithBarrett II (0.47±0.54D) andhighestwaswithHaigis (0.84±0.72D), in mean K≤43.5D grouplowest APE waswith Barrett II (0.40±0.60D) andhighestwaswith SRK II (0.95±0.76D), in mean K>43.5D grouplowest APE waswith Holladay 1 (0.67±0.64D) andSRK/T (0.67±0.63D), highest APE was with Haigis formula (1.17±0.93D) (p<0.01). In all patient group, percentage of eyes in range of ±0.50D prediction error according to formulas was; Barrett II %61, Hoffer Q %52.9, Holladay 1 %52.9, SRK/T %47.1, SRK II %32.9, Haigis %30. Conclusion:According to our study, for eyes with avarage AXL and mean K values Barrett II formula, for eyes with short AXL and/or high mean K values Holladay 1 formula gave better results. Haigis formula had statistically highest predictive error in all formulas. KeyWords: Intraocular lens power, Pediatriccataract,AbsolutePredictiveerror