Accuracy of Holladay 2 formula using IOLMaster parameters in the absence of lens thickness value

Background The accuracy of the Holladay 2 (H2) formula is well-documented. This formula requires seven variables to estimate effective lens position (ELP) for the IOL power calculation. The lens thickness (LT) value is one of the required variables. Interestingly, the IOLMaster, which is one of the most commonly used optical biometers, can provide all the required ocular variables except LT value. It has become a pertinent issue to evaluate the accuracy of theH2 formula when it is used without the LT value. The purpose of this study was to evaluate the results when using the H2 formula, without the LT value, and compare such results to those obtained using the Haigis formula and the Hoffer Q formula.