Visual Acuity refers to clarity of sight. It is commonly measured using the Snellen chart and noted, for example, as 20/20, 20/50, 20/200 etc. Visual acuity becomes blurred in various refractive conditions, for example, myopia (nearsighted), hyperopia (far-sighted), astigmatism (mixed), and presbyopia (age related loss of focusing).
Visual Field is the complete central and peripheral range, or paNORAma of vision. Various neurologic conditions, such as stroke, cause characteristic losses of the visual field, for example hemianopsia. The person may, or may not, concurrently demonstrate a visual neglect which is a perceptual loss of vision and visual motor integration to the side of the visual field loss.