To evaluate the effect of axial length (AXL) and anterior chamber depth (ACD) on the accuracy of the Haigis formula in comparison to its effect on other 3rd generation IOL power calculations. The possibility of measurement error in ACD using either method was also investigated.

A study was performed on 137 eyes of 98 patients who underwent cataract surgery in our hospital. AXL and ACD were measured using IOL Master, and IOL power was calculated using the Haigis, SRK/T, Hoffer Q, and Holladay 1 formulas. ACD was also measured using Pentacam. Patients were divided into 3 groups based on ACD and AXL. Mean numeric error and mean absolute error were analyzed 1 month after surgery.

Five formulae showed no significant difference in refractive error in the 3 groups based on AXL. In contrast, the Haigis formula showed statistically significant differences in the group with shallow ACD, in which hyperopic shift was also demonstrated. The difference in ACD between using IOL Master and using Pentacam was significant in the shallow ACD group, with IOL Master showing more shallow measurement. However, the other groups based on ACD showed no significant difference in the refractive error from the Haigis formula, and in the difference in ACD between measurements.

Errors in ACD measurement should be taken into consideration for discrepancy between the Haigis formula measurement and other formula measurements. The authors of the present study suggest that ACD-driven refractive error should be considered in determination of IOL.