Mathematics. 1  Also called relative maximum, local maximum. the value of a function at a certain point in its domain, which is greater than or equal to the values at all other points in the immediate vicinity of the point. 2  the point in the domain at which a maximum occurs.
For other uses, see Blindness (disambiguation). Visual impairment, also known as vision impairment or vision loss, is a decreased ability to see to a degree that causes problems not fixable by usual means, such as glasses. Some also include those who have a decreased ability to see because they do not have access to glasses or contact lenses.
The standard definition of normal visual acuity is the ability to resolve a spatial pattern separated by a visual angle of one minute of arc. Consider a circle which contains 360 degrees. One degree contains 60 minutes. Therefore, a visual angle of one minute of arc is 1/60 of a degree.f you require glasses because your optometrist says you have 20/60 vision, that means you are able to discriminate characters on an eye chart at 20 feet that a person with normal acuity can see at a distance of 60 feet. 6/6 means the same thing only in meters.