Laboratory science: Predicting the performance of accommodating intraocular lenses using ray tracing

PURPOSE: To predict and compare the amount of accommodation achievable by pseudophakic accommodating intraocular lenses (IOLs) using optical ray-tracing analysis. SETTING: Computational laboratory. METHODS: Two-element IOLs (2E-IOL, with mobile front or back optical elements) were compared with single-element IOLs (1E-IOL). Modeling using computer-assisted ray tracing of both IOL types assumed lens elements were equiconvex/equiconcave. The 4 possible combinations of configurations representing a wide range of varying positive and negative power (up to +40 diopters [D]) of front and back optical elements were evaluated. RESULTS: The 1E-IOLs offered limited amplitude of accommodation with axial shift (approximately 1.2 D/mm). For 2E-IOLs, configurations with high positive-power front elements returned the best amplitude of accommodation (up to approximately 3.0 D/mm when the front element power was +40 D). CONCLUSIONS: Considering the maximum potential amounts of axial shifts available, 1E-IOLs were predicted to provide 1.0 D of accommodation or less and 2E-IOLs were predicted to provide up to 3.0 D to 4.0 D depending on design configuration and amount of axial shift achievable. Potential issues relating to accommodative aniseikonia and spherical aberration have been identified.