Comparison of Two Formulae (SRK-T and Hoffer Q) for Intraocular Lens (IOL) Power Calculation in Eyes with Short Axial Length (AL) <22mm

Aim: To compare the mean predictive error calculated with Hoffer-Q versus SRK-T formulae for intraocular lens (IOL) power calculation in eyes with SAL of <22mm. Methods: A total number of 80 patients having age 20-65 years with axial length <22 mm planned for cataract surgery were included in this comparative study. These patients were recruited from July-2017 to January 2018. In all patients, biometry was done using manual keratometer and IOL power was calculated on contact A-scan using SRK-T and Hoffer Q formula. After 3 months of surgery, prediction errors were calculated for both formulas. Data analysis was carried out using SPSS version 19 Software. Independent sample t-test was used to compare mean prediction error values by using Hoffer-Q formula versus SRK-T formula. Results: The mean age of patients included in this study was 45.49 +/- 11.28 years. There were 45 (56.25%) male patients and only 35(43.75%) female patients. Mean predictive error using Hoffer Q formula was 0.59 +/- 0.26 D versus 0.78 +/- 0.18 D using SRK-T formula (p-value < 0.0001). Conclusion: Hoffer Q formula is better than SRK-T formula for calculation of intra-ocular lens power in eyes with SAL of <22 mm. Hoffer Q formula should be used as a first line choice for calculation of intra-ocular lens power in eyes with short axial length.