AGING AND THE SENSES
All of the senses may be diminished in old age. In the eye, cataracts may make the lens opaque. The lens also loses its elasticity and the eye becomes more farsighted, a condition called presbyopia. The risk of glaucoma increases, and elderly people should be tested for it because treatment is available that can prevent blindness. Macular degeneration, in which central vision becomes impaired first, is a major cause of vision loss for people over 65. Reading and close work of any kind become difficult.
In the ear, cumulative damage to the hair cells in the organ of Corti usually becomes apparent some time after the age of 60. Hair cells that have been damaged in a lifetime of noise cannot be replaced (regrowth of cochlear hair cells has been stimulated in guinea pigs, but not yet in people). The deafness of old age ranges from slight to profound; very often high-pitched sounds are lost first, while hearing may still be adequate for low-pitched sounds. The sense of equilibrium may be diminished; the body is slower to react to tilting, and falls may become more frequent.
Both taste and smell become less acute with age, which may contribute to poor nutrition in elderly people.