| A computer based simulator for continuous curvilinear capsulorrhexis procedure is designed. The goal is to develop a high performance haptics-, physics- and graphics-enabled simulator. High fidelity haptic feedback is rendered to provide the sense of real surgery feelings. The deformable capsule is modeled with position-based dynamics with improved performance over traditional mass-spring models, and solves the super elasticity problem. A customized tearing algorithm with full controllability is developed, to simulate the tearing/capsulorrhexis procedure. A combination of vertex and fragment shaders is adopted to provide improved realism on graphical/visual effect.Evaluation results from two rounds of experiments by residents and attending surgeons from four major U.S. ophthalmology programs are reported.The first round of experiments with residents having varying level of cataract surgery experience is conducted to collect feedback in the initial design phase. Statistical analysis and subjective review of the experiments show encouraging results, and most participants feel that the simulation would be useful in improving their surgical skills. Based on the feedback and collaboration with experienced ophthalmology surgeons, the architectural design and functionalities of the simulator are further improved for usability and realism.The second round of experiments with residents in PGY 4 having moderate cataract surgery experience is conducted to validate the performance of the simulator. Four objective performance metrics, including the total duration, the number of lens hits, the number of re-grab and circularity of the capsulorrhexis, are logged by the simulator during training. The hypothesis for the validation of the simulator is, if there is correlation between performances on the simulator and performances on real surgery, for the same performance metrics measured, these two values should be proportional. Unfortunately, no strong evidence of correlation could be established, though parts of the experiment results satisfy this hypothesis. |
