Recently, patients who complaining visual disability by an accident is increasing. Visual system consists of the eyes and supporting structures, the neural pathways, and the visual cortex of the brain. And criteriaes form many other institutes have some differences. So there is troublesome problems for clinicians to make a visual disability evaluation and grading. In this chapter, I will introduce criteria for evaluating permanent impairment of visual system as it affects an individual's ability to perform activities of daily living and show some clinical case examples for visual disability rate calculation. To assess the visual disability, clinician should perform many ophthalmologic examinations according to the standardized technique and patient's background should be taken into account together.