With advancing years, the ability of the normal eye to adapt to different distances deteriorates. In middle life just about everyone needs a different correction for close work as people read within a range of 30-50 cm, with spectacles occasionally being prescribed vocationally against special needs such as computer screens. The definition does not include reading vision but, at this level, people would not have access to ink-print such as newsprint without special devices. In Europe and other industrialised countries, visual disability can be viewed as a penalty of ageing. Impairment is any reduction of function.
Disability is when that impairment makes any task difficult or impossible.
Handicap is when the individual actually wishes to perform that task. Maximum legibility is achieved if print is well spaced, sans serif, bold and well contrasted with the background. The process of reading is not a smooth continuous flow across the print. Most ink-print uses a light coloured background with dark print. This arrangement is so familiar that it is not usually appreciated that the eye sees the background rather than the figure.