Evaluation of a New IOL Power Calculator in Cataract Patients with Normal and Long Axial Lengths.

Purposes: To evaluate the accuracy of Ophtha Top and consistency between Ophtha Top and IOLMaster 500 in intraocular lens refractive power calculation among cataract patients with normal and long axial lengths. Methods: This study included cataract patients scheduled for phacoemulsification and IOL implantation surgery. The IOL power was calculated using Ophtha Top and IOLMaster 500 (integrated with SRK/T, Hoffer Q, Holladay 1 formula). The accuracy of IOL power calculation between Ophtha Top and IOLMaster 500 was compared. Bland-Altman plots were also used to assess agreement between Ophtha Top and IOLMaster 500. Results: Ninety-four patients (94 eyes) were included. The mean values of the arithmetic and absolute prediction errors of Ophtha Top were -0.22 ± 0.62 D and 0.52 ± 0.40 D for whole sample. Absolute refractive error showed no significant difference between Ophtha Top and IOLMaster 500 using 3 traditional formulas in eyes with normal and long axial lengths. In normal eyes, mean and medium absolute error of Ophtha Top was 0.49D and 0.48D, which were comparable to that of IOLMaster 500 (Hoffer Q:0.47D; 0.40D & Holladay 1: 0.48D; 0.37D). Similar trend was found in long eyes (Ophtha Top:0.58 D & IOLMaster using SRK/T:0.53D). Conclusions: Ophtha Top based on real ray-tracing method could provide predictable outcomes in all eyes, which was comparable to outcomes from IOLMaster 500 using SRK/T, Hoffer Q, Hollday 1 formula. Ophtha Top would be a promising alternative choice for IOL power calculation.