Evaluation of Crystalline Lens Equatorial Plane: A Novel SS-OCT Biometry Parameter For Predicting Postoperative...

To evaluate whether the equatorial lens plane (EQ), estimated using swept-source optical coherence tomography (SS-OCT) biometry and custom-developed software, improves the prediction of postoperative intraocular lens (IOL) position compared to conventional biometric parameters.

Prospective, consecutive, comparative accuracy and validity analysis.

A total of 185 eyes from 185 patients undergoing cataract surgery with phacoemulsification and in-the-bag IOL implantation were included. The cohort included 76 male (41.1%) and 109 female (58.9%) patients, with a mean age of 71.6 ± 8.2 years.

Preoperative SS-OCT biometry was obtained using the Anterion platform. The EQ was defined as the distance from the corneal epithelium to the line connecting the intersection points of the anterior and posterior lens curvatures. A semi-automatic Python 3 software was used to detect lens surfaces and calculate the EQ parameter. Postoperative SS-OCT imaging was performed to measure IOL position. Linear regression models were built to evaluate the predictive performance of EQ and conventional biometric variables.

Postoperative IOL position prediction accuracy, assessed using adjusted R², mean absolute error (MAE), and root mean squared error (RMSE).

The EQ showed a strong correlation with postoperative IOL position (r = 0.82, P < .0001). A conventional model including ACD, LT, and WTW achieved an R² of 0.644 and RMSE of 0.148. A simple regression using EQ alone improved R² to 0.670. The best-performing model included EQ-related parameters-lens rise from the EQ plane and from angle-to-angle-achieving an R² of 0.709 and RMSE of 0.133 (P < .0001 vs. conventional model). In eyes with axial length > 24.5 mm, the inclusion of EQ-related metrics improved prediction significantly (R² = 0.717, RMSE = 0.107; P = .045).

Models incorporating LEP demonstrated superior accuracy compared to those based on conventional parameters. These findings support testing the integration of LEP into the next-generation IOL power calculation formulas.