The commonly used correction methods of ametropia are all focused on correcting a certain static value of human-eye aberration; however, these methods cannot effectively correct the dynamic changes in human-eye aberration. To solve this problem, a dynamic compensation system is developed to correct the eye's defocusing of humans based on image processing. The system consists of a dynamic measurement system for pupil size composed of an infrared camera and an image processing program, and a dynamic correction system for refractive power composed of a transmission deformable mirror and a control program as the core. The system prototype is built on the optical experimental platform, where the corresponding experiments are performed. The results show that the system can assess the accurate measurement of the pupil size and ensure an accurate, fast, and smooth correction of the corresponding defocus aberration under different light intensities, thereby preliminarily confirming the feasibility and effectiveness of the proposed method and system.