Abstract: Today science has witnessed major developments and rapid increase in ecent creations and inventions in all fields including medical engineering, which has witnessed a marked improvement in human creations that serve this field and explain the design of the mechanical movement of the human eye, which consists of three movements, primary and secondary and tertiary. A biomechanical model will be modified upon a homomorphic saccadic eye movement model by adding and calculating the mass of eye and the elasticity of eye tendon and take a primary position only. According to this modification, equation with six order will be appeared which is process with a MATLAB SIMULINK and get a desire results of theta, velocity and acceleration in the normal case. Then for the same model, a disease will be estimated to evaluate the results of theta and how it is affected by this disease which is estimate the increase and decrease happened in the primary elastic element se K and viscosity 2 B . After that a controller will be added to the model to control the system and get the desire angle which is equal to 15° in the normal case and during disease but the PI controller that used can control only the system during normal case while in the system with disease, the PI controller could not control the system to get the desired angle.