health programs for all ages. However, some elements of visual function are not altered with age (Enoch et al., 1999), and a substantial proportion of these sense organ decrements, such as myopia, hyperopia, and accommodation loss, are correctable with appliances or surgical procedures, with the expectation of improved function.
Age-related hearing loss, known as presbycusis, is very common, and can occur in 20 to 25 percent of persons 65 to 75 years of age (Seidman, Ahmad, and Bai, 2002). The causes are not well understood, and a variety of genetic and environmental factors have been suggested. There are apparently substantial differences in presbycusis among populations defined geographically or socioeconomically, suggesting the importance of nonoccupational noise and other environmental factors. Among the most important occupational causes is noise exposure, and considerable effort has been spent understanding the mechanisms and management (Prince, 2002). Other toxic exposures, including exposures to chemicals and medications, have been linked to progressive hearing loss and may have occupational implications. Some of these factors may be synergistic with occupational noise exposure.
Occupational hearing loss is an important cause of monetary compensation in the United States (Dobie, 1996). Severe hearing loss is often related to systemic illness or disorder and cochlear disease, which may have concomitant balance, communication, and other health problems that can impair worker function. While some traumatic and infectious causes of hearing loss are treatable, most occupational hearing loss is not curable, and rehabilitation must be made available (Irwin, 2000). This highlights the importance of the availability of general safety and prevention programs throughout a worker’s career. There is relatively little research into the functional and health consequences to workers of mild to moderate hearing loss.
Physiological aging of the lung is associated with dilation of the alveoli, enlargement of airspaces, decrease in exchange surface, and loss of supporting tissue for peripheral airways. These changes result in decreased elastic recoil and increased residual volume and functional residual capacity (Janssens, Pache, and Nicod, 1999). Most dimensions of pulmonary function, measured using physiological testing methods, decline with age, due to a variety of clinical, climatic, and other factors (Babb and Rodarte, 2000). How much of this is attributable to normal aging is uncertain because of