Visual acuity refers to the ability of the body’s retina to resolve spatial resolution. Visual acuity is usually divided into two types: central vision and peripheral vision. Normal central vision should be at least 1.0 for children and adults over 8 years old. Strictly speaking, normal visual acuity should be at least 1.0 without glasses corrected central visual acuity (also known as naked eye vision). Since there are many people with refractive errors, it is normal to have a vision of 1.0 or higher with general glasses through medical optometry. Peripheral vision refers to the extent to which the eye can see a target in the non-gaze area. Many diseases can cause varying degrees of peripheral vision loss, also known as visual field impairment. A visual field examination is required to check whether peripheral vision is normal. It is important to note that normal vision is actually age dependent. In addition, visual acuity is a subjective examination and can fluctuate depending on factors such as attention and cooperation, especially in young children, where a single examination of visual acuity below normal does not necessarily mean there is a problem.