Vision and hearing
Accommodation of the eye-the ability to focus and maintain an image on the retina-declines sharply between 40 and 59 years of age . In particular,middle aged individuals begin to have difficulty viewing close objects,which means that many individuals have to wear glasses with bifocal lenses - lenses with two sections that enable the wearer to see items at different distances (achiever,2006). Also,there is some evidence that the retina becomes less sensitive to low levels of illumination . Laser surgery and implantation of intraocular lenses have become routine procedures for correcting vision in middle-aged adults (Ang,Evans,&mehra,2012).
Hearing also can start to decline by the age of 40(Roring,Hines,&charness,2007). Sensitivity to high pitches usually declines first. The ability to hear low pitched sounds does not seem to decline much in middle adulthood, though.Men usually lose their sensitivity to high-pitched sounds sooner
Than women do. How ever, this gender difference might be due to men's greater exposure to noise in occupations such as mining , automobile work,and so on (Scialfa&Kline , 2007) . Also, recent advances in the effectiveness of hearing aids are dramatically improving the hearing of many aging adults (Banerjee,2011).