Effect Of Ablation Decentration On Iol Power Calculation In Post-Laser Refractive Surgery Cataract Patients

Evaluate the correlation between different methods of calculating ablation eccentricity after myopia laser surgery, explore the influence of eccentricity value on postoperative error in cataract patients, and compare the accuracy of predicting intraocular lens (IOL) power with different curvature values for ablation eccentricity patients

cross-section study

Myopic cataract patients post-myopia laser refractive surgery were enrolled. Pentacam measured corneal thinnest point eccentricity and laser ablation center coordinates via tangential topography; ablation eccentricity was calculated by concentric fitting, analyzing its consistency with the former. IOL Master700 obtained ocular biometrics, Km applied to Barrett True-K for IOL power calculation. Postoperative refraction ≥4 weeks calculated PE, recording ME, APE, MAE, MedAE and ±0.50D/±1.00D PE rates to analyze eccentricity-refractive error correlation. Different curvature values (Pentacam: Kapex, Kupil, TCRP; IOL Master: Km, TK) were compared for IOL power prediction accuracy in eccentric patients.

This study enrolled 58 patients (77 eyes). Spearman analysis showed ablation eccentricity correlated with corneal thinnest point eccentricity (r=0.291, P=0.01), and APE with both (ablation: r=0.324, P=0.004; corneal: r=0.306, P=0.007). Patients were subgrouped by ablation (≤0.5/>0.5) and corneal eccentricity (≤0.6/>0.6) via polynomial regression inflection points. For ablation ≤0.5, K Master K performed best (MAE 0.43D, MedAE 0.36D, ±0.5D PE 65.91%); >0.5 (n=30), Kpupil was optimal (MAE 0.77D, MedAE 0.53D, ±0.5D PE 51.52%). For corneal ≤0.6 (n=60), K Master K was best (MAE 0.52D, MedAE 0.38D, ±0.5D PE 61.66%); >0.6 (n=17), Kpupil performed best (MAE 0.88D, MedAE 0.86D, ±0.5D PE 35.29%).

IOL power prediction accuracy in post-laser myopia cataract patients declines with increasing ablation eccentricity. Ablation eccentricity is positively correlated with corneal thinnest point eccentricity, allowing clinical calculation of ablation zone eccentricity from the corneal thinnest point. Kupil is recommended for IOL power calculation in patients with a high corneal thinnest point eccentricity value.