Topical Review: Causes of Refractive Error After Silicone-oil Removal Combined with Cataract Surgery

The LISA-PPV Formula: An Ensemble Artificial Intelligence-Based Thick Intraocular Lens Calculation Formula for Vitrectomized Eyes

PURPOSE

To investigate the relationship between effective lens position (ELP) and patient characteristics, and to further develop a new intraocular lens (IOL) calculation formula for cataract patients with previous pars plana vitrectomy (PPV).

DESIGN

Cross-sectional study.

METHODS

A total of 2793 age-related cataract patients (group 1) and 915 post-PPV cataract patients (group 2) who underwent phacoemulsification with IOL implantation were included. The ELP of 2 groups was compared and the association between ELP and patient characteristics was further evaluated using standardized multivariate regression coefficients. An ensemble artificial intelligence-based ELP prediction model was developed using a training set of 810 vitrectomized eyes, and a thick-lens IOL formula (LISA-PPV) was constructed and compared with 7 existing formulas on an external multi-center testing set of 105 eyes.

RESULTS

Compared to eyes with age-related cataract, vitrectomized eyes showed a similar ELP distribution (P = .19), but different standardized coefficients of preoperative biometry for ELP. The standardized coefficients also varied with the type of vitreous tamponade, history of scleral buckling, and ciliary sulcus IOL implantation. The LISA-PPV formula showed the lowest mean and median absolute prediction error (MAE: 0.63 D; MedAE: 0.44 D), and the highest percentages of eyes within ±0.5 D of prediction error (57.14%) in the testing dataset.

CONCLUSIONS

The ELP prediction required optimization specifically for vitrectomized eyes based on their biometric and surgical characteristics. The LISA-PPV formula is a useful and accurate tool for determining IOL power in cataract patients with previous PPV (available at http://ppv-iolcalculator.com/).

Correction of axial length measurement error by IOLMaster 700 could improve refractive prediction accuracy in silicone oil-filled eyes

PURPOSE

To determine whether correcting the axial length (AL) measurement error of the IOLMaster 700 could improve the refractive prediction accuracy in silicone oil-filled eyes.

METHODS

This study included 265 cataract patients (265 eyes) with silicone oil tamponade who were scheduled for phacoemulsification with intraocular lens (IOL) implantation. The performances of various formulas, including Barrett Universal II, Emmetropia Verifying Optical, Hoffer-QST, Kane, Ladas Super Formula, Pearl-DGS, Radial Basis Function and traditional formulas (Haigis, Hoffer Q, Holladay 1 and SRK/T), were evaluated. The refractive prediction errors (PE) calculated with measured AL (ALmeas ) and corrected AL with silicone oil adjustment (SOAL ) were compared. Subgroup analysis was performed based on the ALmeas (<23 mm; 23-26 mm; ≥26 mm).

RESULTS

Using SOAL significantly reduced the hyperopic PE of formulas when compared to ALmeas (-0.05 to 0.17 D vs 0.15 to 0.38 D, p < 0.001). After applying AL correction, all formulas showed a lower mean absolute PE (0.47-0.57 D vs 0.50-0.69 D). The percentage of eyes within ±1.0 D of PE increased from 84.91%-88.68% to 89.81%-91.32% for new formulas and from 78.11%-83.40% to 85.66%-88.68% for traditional formulas, with the use of SOAL . Subgroup analysis showed that the majority of formulas with SOAL in prediction accuracy for eyes with an AL ≥26 mm (p < 0.05).

CONCLUSIONS

The refractive prediction accuracy in silicone oil-filled eyes was improved by correcting the AL measurement error of the IOLMaster 700, especially for long eyes.

Choice of intraocular lens calculation formula for cataract patients with prior pars plana vitrectomy

PURPOSE

To determine the optimal intraocular lens (IOL) calculation formula for vitrectomized eyes with diverse surgical and biometric characteristics.

SETTING

Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.

DESIGN

Retrospective consecutive case series study.

METHODS

This study included 974 vitrectomized eyes (974 patients) scheduled for phacoemulsification with IOL implantation. 11 formulas were evaluated: Barrett Universal II (BUII), Emmetropia Verifying Optical, Hoffer-QST, Kane, Ladas Super Formula, Pearl-DGS, Radial Basis Function (RBF), Haigis, HofferQ, Holladay1, and SRK/T. Risk factors for prediction error (PE) exceeding 1 diopter (D) were determined using multiple logistic regression. Subgroup analyses were performed based on surgical history and biometric parameters.

RESULTS

The risk of hyperopic PE (>1 D) was higher in patients with silicone oil tamponade (odds ratio [OR], 1.82) and longer axial length (AL) (OR, 1.55), while patients with previous scleral buckling (OR, 2.43) or ciliary sulcus IOL implantation (OR, 6.65) were more susceptible to myopic PE (<-1 D). The Kane formula had the highest overall prediction accuracy, and also the best in silicone oil-filled eyes and the flat cornea subgroup. The BUII and RBF displayed the optimal performance in eyes with previous scleral buckle and steep cornea, respectively. In eyes with an AL ≥ 26 mm, the Holladay1 with the nonlinear version of the Wang-Koch AL adjustment (Holladay1-WKn) showed the lowest absolute PE and highest percentage within ± 1.0 D of PE.

CONCLUSIONS

The Kane achieved the highest overall prediction accuracy in vitrectomized eyes. The optimal formula for eyes with previous scleral buckle, steep cornea, or long AL was BUII, RBF, and Holladay1-WKn, respectively.