[Reasonability of accounting for gender in intraocular lens power calculation]. / O tselesoobraznosti ucheta gendernoi prinadlezhnosti pri raschete opticheskoi sily intraokulyarnykh linz.

PURPOSE: The study assesses the influence of gender on the accuracy of intraocular lens (IOL) power calculation by formulas SRK/T, Barrett Universal II (BUII), Ladas super formula (LSF), Hill RBF (RBF) and Kane. MATERIAL AND METHODS: The study enrolled 214 patients (106 men and 108 women) who underwent cataract phacoemulsification (PE). Optical biometry was performed on IOL-Master 500. IOL power calculation was performed either adjusting for gender (formulas SRK/T, BUII, LSF) or without such adjustment (formulas RBF, Kane). Calculation error (CE) was assessed one month after PE by comparing the achieved (autorefractometer Topcon-8800) and target spherical equivalent of refraction. RESULTS: Significant differences were found in mean IOL CE with gender-unspecific formulas (SRK/T, BUII, LSF) and no differences in gender-specific calculators (RBF, Kane). The Kane formula demonstrated the lowest CE between men and women (-0.01±0.43 versus -0.09±0.41 D; p=0.158), while the SRK/T formula had the highest CE (0.02±0.46 versus -0.21±0.44 D, respectively; p<0.001). Presence of a significant correlation between CE and gender was found for all formulas except Kane (R2=0.005, p=0.158). CONCLUSION: Patient's gender has a significant impact on IOL calculation accuracy. Using gender-responsive formulas could help achieve better refractive results with PE. The present study showed Kane formula to have the least CE dependence from gender. However, the CE difference (less than 0.25 D) was lower than the value of division (0.5D) in modern IOL models.

[Alternative method of intraocular lens power calculation in eyes with short axial length]. / Al'ternativnyi sposob rascheta opticheskoi sily intraokulyarnykh linz pri korotkoi perednezadnei osi glaza.

PURPOSE: To develop an alternative method of intraocular lens (IOL) power calculation in eyes with mature cataract and axial length (AL) of less than 22.0 mm using modern formulas Barrett Universal II and Hill RBF. MATERIAL AND METHODS: The study enrolled 41 patients (41 eyes) who underwent phacoemulsification (PE). Ultrasound biometry (Tomey Biometer Al-100) and keratometry (Topcon-8800) were used for IOL power calculation by SRK/T and Haigis formulas. To calculate IOL power by Barrett Universal II and Hill RBF formulas, 0.2 mm were added to AL measured with ultrasonography (retinal thickness). One month after PE, spherical equivalent of refraction was compared with target refraction (calculated by the formulas listed above), and based on that a conclusion was made on the accuracy of calculations. RESULTS: Haigis formula was found to be the least accurate (IOL calculation error -0.39±0.79 D). The calculation error in SRK/T (0.04±0.79 D), Barrett Universal II (0.02±0.79 D) and Hill RBF (-0.05±0.73 D) formulas was much lower. However, among them Hill RBF had the lowest spread of the mean absolute IOL calculation error. Pairwise comparison revealed significant difference of mean IOL calculation error by Haigis formula versus the others. There was no significant difference in the following pairs: SRK/T - Barrett Universal II (p=0.855), and SRK/T - Hill RBF (p=0.167), but there was a significant difference (p=0.043) in the Barrett Universal II - Hill RBF pairdue to the tendency for slight hypermetropic calculation error in the former and the inherent slight myopic shift in the latter.. CONCLUSION: The proposed alternative method of IOL power calculation in eyes with mature cataract and short AL using modern formulas (Barrett Universal II and Hill RBF) shows higher accuracy compared to the formulas embedded in ultrasound biometer (SRK/T and Haigis), and can be recommended for use in everyday practice.

A comparative study on calculation of intraocular lens power using different formulas between IOLMaster 700 and IOLMaster 500 in cataract eyes / 中华实验眼科杂志

Objective:To compare the accuracy of IOLMaster 700 and IOLMaster 500 in intraocular lens (IOL) power calculation.Methods:A cross-sectional study was conducted.Two hundred and sixty-two eyes of 262 patients who underwent phacoemulsification combined with IOL implantation at the Eye Hospital of Wenzhou Medical University from November 2018 to November 2019 were enrolled.Preoperative biometry for cataract surgery was performed using IOLMaster 700 and IOLMaster 500.IOL power was calculated through the built-in formulas, Haigis, Holladay Ⅰ, Hoffer Q and SRK/T of the two devices.The difference in IOL power calculation between the two devices was analyzed through the prediction error of IOL power calculation using different formulas across different axial length (AL) ranges.This study complied with the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Eye Hospital of Wenzhou Medical University (No.2020-038-K-33). Written informed consent was obtained from each patient before the surgery.Results:There was no significant difference in mean absolute error (MAE) between IOLMaster 700 and IOLMaster 500 using Haigis, Hoffer Q and SRK/T over the entire AL range (all at P >0.05). The MAE of IOLMaster 500 was 0.47 (0.24, 0.90) D, which was significantly lower than 0.50 (0.28, 0.99) D of IOLMaster 700 using Holladay Ⅰ formula ( Z=-3.120, P=0.002). When AL was <22.0 mm and ≥24.5 mm-<26.0 mm, there was no significant difference in MAE between the two devices using the four formulas (all at P >0.05). When AL was ≥22.0 mm-24.5 mm, there was no significant difference in the MAE between the two devices using Haigis, Hoffer Q and SRK/T (all at P >0.05), but 0.42 (0.18, 0.75) D from IOLMaster 500 was smaller than 0.45 (0.25, 0.79) D from IOLMaster 700 using Holladay Ⅰ, showing a statistically significant difference ( Z=-3.487, P <0.001). But the difference was negligible and therefore was of no clinical significance.When AL was ≥26.0 mm, there was no statistically significant difference in the MAE between the two devices using Haigis, Holladay Ⅰ and SRK/T, but 0.66 (0.38, 1.00) D from IOLMaster 500 was significantly smaller than 0.98 (0.62, 1.32) D from IOLMaster 700 using Hoffer Q ( Z=-3.046, P=0.002). Conclusions:The refractive prediction accuracy of IOLMaster 700 and IOLMaster 500 using Haigis, Hoffer Q and SRK/T is similar over the entire AL range.For patient with long AL, the IOL calculation from IOLMaster 700 using Hoffer Q is significantly larger than that from IOLMaster 500, which requires extra caution in clinical practice.The accuracy of IOLMaster 700 and IOLMaster 500 for IOL prediction is very similar.

Study on the measurement formula of intraocular lens in primary hospitals of minority areas / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To compare and study the differences of eyeball biometric measurements among Han, Hani and Yi nationality in Honghe Hani and Yi Autonomous Prefecture(Honghe Prefecture), and prediction accuracy of the intraocular lens(IOL)degree by SRK-T and Haigis formulas in the different eye axes, to provide further objective clinical evidence for the majority of basic-level hospitals and the blind prevention and treatment projects in minority areas.<p>METHODS: Selected 186 cases(200 eyes)cataract patients in our department, divided them into three groups according to different nations, get their eyeball biometric measurements(ocular axial length, anterior chamber depth and corneal curvature)by A-ultrasound combined with corneal curvature meter and corneal topography, and then compared the differences. According to the different eye axes, they were divided into three groups and then randomly divided into two groups. SRK-T and Haigis formulas were used to predict the IOL degree, and collected postoperative optometry results, calculated the absolute prediction error, then conducted statistical analysis. <p>RESULTS: There were no difference in the mean axial length, mean anterior chamber depth and mean corneal curvature(measured respectively by corneal topography and corneal keratometer)in the different ethnic groups(<i>P</i>>0.05), and the mean corneal curvature measured by the two methods had no difference(<i>P</i>>0.05). There were no difference of the mean corneal curvature measured by the two methods in the three axial eye groups(<i>P</i>>0.05)and in the same axial eye group(<i>P</i>>0.05). There were no difference in the absolute error of the two IOL measurement formulas in the three eye axis groups(<i>P</i>>0.05). The absolute error calculated by SRK-T formula for the short and the middle eye axis groups were smaller, while it calculated by Haigis formula for long eye axis group was smaller.<p>CONCLUSION: In our department, there are no statistical difference in the eye biometrics of Han, Yi and Hani nationality. Corneal curvature measured by corneal topography and corneal keratometer have no significant difference. SRK-T and Haigis formula both have high predictive value for IOL degree, SRK-T formula has smaller predictive error for patients which with short and middle eye axis, and Haigis formula has better predictive value for the long ones.