Effects of capsulorhexis size and position on post-surgical IOL alignment

In cataract surgery, post-surgical stability of the intraocular lens plays a major role. This study aims to explore how the size and decentration of the capsulorhexis affect intraocular lens decentration and tilt by using numerical methods. Finite element models included zonules, ciliary body, capsular bag, and an IOL with two open-loop haptics were built. Capsulorhexes were modeled with a 4.5- and 5.5-mm diameter. The capsulorhexis was shifted 0.5-1 mm in two in-plane directions normal to the optical axis. Three IOLs with different powers (5 D, 29 D, and 34 D) were compared. The results were also compared with currently published numerical and clinical studies. With different capsulorhexes sizes and locations, the decentration varied from 0.43 to 8.3 μm, and the tilt varied 0.02° - 0.09°. The 34 D lens had the largest tilt and decentration when capsulorhexis changed sizes or decentered. The simulation showed that capsulorhexis size and decentration have only a minor effect on IOL decentration or tilt that will in most cases not be noticeable to the patient.