A study on efficacy of various formulas for intraocular lens power calculation in hyperopic patients at a tertiary care center

Purpose: Our study was conducted to evaluate and compare the predictive capacity of five intraocular lens (IOL) power calculation formulas (SRK/T, HOFFERQ, HOLLADAY1, HAIGIS, BARRETT UNIVERSAL II) in eyes with axial length (AL) <22 mm. Subjects and Methods: In our study, 100 patients with a preoperative AL of <22 mm were included. All patients underwent uneventful cataract surgery with IOL implantation and postoperative target of refraction were analyzed after 40 days. The mean estimation error and mean absolute error (MAE) were calculated for each formula, and ANOVA test was applied to compare the differences in the MAEs of the formulas. A statistically significant difference was defined as P < 0.05. Results: A statistically significant difference was seen between Barrett Universal II formula in comparison to SRK/T formula. There was no statistically significant difference seen among the absolute error of all the five IOL power calculation formula groups. Conclusions: Among the formulas compared, Barrett Universal II formula is the most accurate in predicting postoperative refractive error in hyperopic patients. Hoffer Q, Haigis, and Holladay 1 formula give better results than the commonly used SRK/T formula.