The Importance Of Acd, Lt, And Wtw In Predicting Post-Operative Refraction Using The Barret Universal Ii, Kane, And Hill-Rbf Formulas

To evaluate the importance of the anterior chamber depth (ACD), lens thickness (LT), and white-to-white (WTW) in predicting the final post-operative refraction using modern formulas.

A retrospective study of 206 consecutive eyes that underwent cataract surgery at the department of ophthalmology, Edith Wolfson Medical Center, Holon, Israel.

The Barret Universal II (BUII), Kane, and Hill-RBF formulas were calculated for each eye with all combinations of omitting ACD, LT, and WTW, as possible by each formula. Lens constant optimizations were executed. The results were compared to the 2-week post-operative refraction.

For BUII, except for the LT variation, which lacked statistical significance, all other variations demonstrated a statistically significant higher median absolute error (MedAE) of 0.006-0.05 (P<0.05) when compared to BU II using all parameters.

All Hill-RBF variations, except for the ACD+LT variation, which lacked statistical significance, displayed a statistically significant higher MedAE of 0.012-0.02 (P<0.05) when compared to Hill-RBF using all parameters.

For the Kane formula, the ACD+WTW variation displayed a statistically significant higher MedAE of 0.03 (P<0.05) when compared to Kane using all parameters.

The BUII, Kane, and Hill-RBF formulas show minor median absolute error when omitting ACD, LT, and WTW. Basing IOL power calculations on the AL and keratometry values is clinically reasonable.