In this paper, we describe a parametric eyeball modeling system for real-time simulation of eye surgery. A knowledge-based approach is used to parametrically model the ophthalmologic structures. Together with the parametric eye modeling and the integration of patient-specific disease images, the ophthalmologic knowledge databases of eye diseases, eye material properties, and eye surgical instruments and procedures can help to provide better maneuverability and more realistic scenarios for eye surgical simulation. A customized Finite Element Method (FEM) is developed to analyze the deformation of the eyeball and the interactions between the bio-structures and the instruments in the surgery simulation. A phantom haptic and force feedback virtual environment is used for real-time interactive ophthalmologic surgical simulation.