Abstract
INTRODUCTION: Patients with retinitis pigmentosa (RP) frequently exhibit zonular weakness, which poses challenges for intraocular lens (IOL) stability and refractive prediction. This study aimed to evaluate the impact of capsular tension ring (CTR) implantation on the predictive accuracy of 12 IOL power calculation formulas in patients with RP receiving cataract surgery. METHODS: We conducted a retrospective cohort study where the predictive accuracy of 12 IOL formulas was assessed using refractive prediction error (PE), mean absolute error (MAE), root-mean-square absolute error (RMSAE), and the percentage of eyes achieving target refraction within ± 0.25 D to ± 1.00 D. These metrics were compared between eyes with (n = 23) and without (n = 30) CTR implantation. The influence of lens thickness (LT) on formula accuracy was also evaluated. RESULTS: In the overall cohort of 53 eyes from 38 patients with RP, the Barrett Universal II (BUII) formula yielded the lowest numerical MAE (0.45 D) and RMSAE (0.56 D), though none of the formulas were statistically superior in RMSAE. In the CTR group, significantly lower MAE was observed for Cooke K6 (P = 0.024), Kane (P = 0.016), Emmetropia Verifying Optical (EVO) 2.0 (P = 0.040), and PEARL-DGS (P = 0.021) compared to the non-CTR group. The CTR group also exhibited a significantly higher percentage of eyes within ± 0.50 D (P = 0.016), ± 0.75 D (P < 0.001), and ± 1.00 D (P < 0.001) of target refraction. Increasing LT correlated with a hyperopic shift for all formulas; however, BUII demonstrated relatively stable MAE across LT quartiles. CONCLUSIONS: Implantation of a CTR was associated with significantly improved predictive accuracy for several modern IOL formulas in patients with RP. The BUII formula showed the highest overall predictive accuracy.