To evaluate of aphakic refraction technique for secondary intraocular lens power calculation in children

methods: 33 eyes of children between 3-14 years old who had been underwent lensectomy due to congenital cataract and were candidates for secondary intraocular lens implantation were enrolled in this study.subjective refraction was performed by an expert optometrist and preoperative aphakic spherical equivalent SE was calculated.Optical biometry was done by lenstar before surgery to calculate secondary IOL power by conventional formulas (SRK-T and holladay) A 3-P PC IOLwas implanted for all patients. postoperative refraction was done and SE was obtained ,the IOL power that would have achieved target refraction(2 diopter hyperopia for children between 3-4.5 years,1 diopter hyperopia for children between 4.5-6 years and emmetropia for children ≥6 years) was calculated retrospectively. an IOL difference was calculated by subtracting this target refraction from IOL power calculated by the 2 formulas using aphakic SE(lanchulev and leccisotti)

results: After surgery, 40% of eyes were within -1.00 to +1.00 diopters.and 66% were within -2.00 to +2.00 diopters Lanchulev formula in all eyes (except one eye) and leccisotti formula in all eyes led to myopia(mean -4.3 diopter myopia for lanchulev and -8.70 diopter for leccisotti). using data and with reduction the coefficient of lanchulev formula,we derived an alternative formula that was comparable with conventional formulas in adult ::.our formula:IOL power=aphakic SEx1.7::

Although based on previous studies in adults lanchulev formula can be applied to most eyes and leccisotti formula shows good performance in myopic eyes,but based on our study in children both formulas lead to significant postoperative myopia.but the new alternative formula reported in our study is comparable with conventional formulas in adult for children and can be used when we can not use biometric formulas in children.