Abstracto

Comparison of Olsen and Barrett-universal II; two intraocular lens power calculation formulas for monofocal intraocular lens in Iranian patients: Kermanshah (2018-2020).

Mojtaba Eidizadeh, Leila Ebadi-soofloo, Ashkan Safarzadehkhoushabi

Background: With improvements in the formulas, the accuracy of predicting IOL power in emmetropic eyes with an Axial Length (AL) of 22.0 to 24.5 mm can now be guaranteed. On the other hand, as the condition of the fundus is complex in highly myopic eyes, many formulas are unable to predict the IOL power accurately; in such cases. Myopia, associated with long Axial Length (AL), is a global public health issue. The estimated incidence of myopia has been reported between 25 to 46.4 mm. The IOL power calculations formulas are less accurate in long eyes, which are commonly defined as AL longer than 24.5 mm.

Material and methods: This prospective cohort study protocol was reviewed and approved by the local university Institutional Ethics Committee and the tenets of the Declaration of Helsinki were followed throughout the study. A written informed consent was obtained from each patient and only those who were consenting and willing for follow?up were enrolled into the study.

Results: Before being included in the study, all patients were informed of its purpose and gave their written consent. The study protocol was approved by the Ethics Committee of the Kermanshah University Medical Sciences and health services, and the study complied with the tenets of the Declaration of Helsinki. Institutional review board approval was obtained for this study. Of the 423 eyes underwent cataract surgery during the study period, Inclusion criteria were met by 250 eyes. 173 eyes were excluded from the study due to inadequate biometry data (n=136); associated ocular comorbidities and previous intraocular surgeries (n=19) or postoperative complications (n=18).

Discussion: In our cohort study on 250 eyes in Iranian patients during 2018 to 2020, the BU II formula was found to be most accurate than Olsen in normal and short axial length eyes; neither long axial length eyes. It also had the lowest MAE, standard deviation of error, median absolute error, and highest percentage of eyes within ± 0.25 D, ± 0.50 D, and ± 1.00 D; all significantly meaningful (pvalue< 0.005).

Conclusion: Our study on 250 Iranian eyes underwent phacoemulsification surgery (microincision cataract surgery) with posterior chamber IOL implantation, and received an in-the-bag insertion of a monofocal IOL between March 2018 and August 2020. After measurement of some refractive information with Lenster L900; data analyses revealed that BUII formula performing more accurately than Olsen formula in eyes with normal or short axial length.