Ability to discern the details of an object. A normal average eye an angle of one minute of arc (1/60th degree). Assessment of the eye’s ability to distinguish object details and shape, using the smallest identifiable object that can be seen at a specified distance (usually 20 ft. or 16 in.) and letter height (8.87mm).
Devices such as magnifiers and closed circuit television sets that can help people with sub-normal vision see more and function better in day to day activities. Also known as Low Vision aids.
A group of conditions characterised by the inflammation of blood vessel walls.