Spherical equivalent prediction analysis in intraocular lens power calculations using Barrett Universal II formula...

To evaluate the prediction accuracy of the Barrett Universal II (BUII) intraocular lens (IOL) formula variations, including optional biometric parameters and sum-of-segments (SOS) axial length (AL) modification, for IOL power calculation in cataract surgery.

Single-center academic university hospital.

Retrospective case series.

1340 eyes of 1340 patients undergoing uneventful cataract surgery were analyzed using 5 BUII variants: with only 1 optional parameter (lens thickness [BUII LT] or white-to-white [BUII WTW]), 2 optional parameters (BUII STD), without optional parameters (BUII WØ), and adjusted for SOS AL (BUII TAL). A single swept-source optical biometer (ARGOS) was used. Spherical equivalent prediction error (SEQ-PE, trueness), SD (precision), and absolute SEQ-PE (accuracy) were calculated with the online Eyetemis tool. Statistical comparisons were conducted using robust statistical methods across the entire cohort and subgroups based on AL: short (<22.0 mm), average (22.0 to 24.99 mm), and long (≥25.0 mm).

All formula variations showed high refractive accuracy. BUII TAL provided superior precision and best accuracy, particularly outperforming other variants in short eyes ( P < .01). For average and long eyes, accuracy and precision differences between the modified BUII TAL and standard BUII STD were minimal and not statistically significant. The percentage of eyes within ±0.50 diopters prediction error was highest for BUII TAL and BUII STD (80%), slightly outperforming other variants.

BUII formula variants demonstrated excellent refractive prediction accuracy. SOS adjustment and optional biometric parameters notably improved precision and accuracy, especially in short eyes.