Think for a moment about the importance of sight and sound. Consider your continual reliance on your vision and hearing for information from your environment. Reflect on the pleasures of perception: the faces and voices of friends and family; a quiet country evening with crickets chirping, fireflies flashing, and a sky of Maxfield Parrish blue, accented with the last rosy rays of sunset.

Like good health, we take our special senses for granted. While some disorders involving the eyes and ears are not preventable, many factors affecting the health of these sensory systems are under our control. Both accidental injury and chronic abuse take their toll on the health of our eyes and ears.

Some things improve with age, but hearing is not one of them. Damage to the hair cells that convert sound waves into nerve impulses accumulates over a lifetime, and by the time hearing loss is discovered, irreversible damage has already occurred. The most common form of hair cell wear and tear is exposure to excessive noise. Damage increases with both the intensity and duration of exposure. The hair cells appear to be less traumatised by short periods of loud noise than by chronic exposure to moderately loud noise.

Excessive noise can be found both at home and in the workplace. Workplaces must abide by certain safety standards to limit workers' noise exposure, either by changing working conditions or supplying hearing protection. Common sources of damaging noise at home include engines (motorcycles, snowmobiles, motorboats, and lawnmowers); power tools (table saws, chain saws); firearms; and loud music, including car stereos, radio headphones, and rock concerts.

What is excessive noise? Noise need not reach the pain threshold to be damaging. Eight hours of noise at the level of most vacuum cleaners is believed to damage hearing. Hearing loss can be prevented, or at least postponed, by avoiding excessive noise and wearing hearing protection whenever necessary.

Eye injury can occur in several ways. Common causes of eye injury include flying particles and dusts, chemical splashes, and radiant light. Studies show that 90% of eye injuries occurring in the workplace are preventable with protective eye wear. Protective eye wear should also be worn at home for tasks . that could lead to eye injury, such as trimming hedges and using power tools.

Eye injury can also occur when playing sports. The most common sports eye injuries are usually caused by the impact of a ball. Ball speeds in squash, racquetball, and baseball often reach 75 to 125 mPh, which can cause serious trauma. Eye injury can also result from getting struck with a racket, hockey or lacrosse stick, golf club, or such; and from collision and body contact. Wearing appropriate eye protection can greatly decrease the likelihood of eye injury.

The ultraviolet (UV) rays of the sun appear to age the eyes, just as they age the skin. Two eye diseases associated with aging are cataracts, in which the lens of the eye loses its transparency, and senile macular degeneration (SMD), in which new blood vessels grow over an area of the retina called the macula lutea, reducing visual clarity. People with light-coloured eyes are most vulnerable to UV damage. Glasses that filter out UV light protect eyes from these damaging rays.

People who smoke have higher rates of cataracts. Researchers estimated that about 20% of all cataracts may be attributed to cigarette smoking. The way in which smoking increases cataract development is unknown, but scientist speculate that it may increase free-radical damage to the lens.

While it has not been conclusively demonstrated that prolonged periods of close work, such as reading and working at a computer (the academic life-style!), can cause near sightedness, it can cause headaches and eyestrain. When involved in close work, look up frequently and gaze into the distance to prevent eyestrain and relax the ciliary muscles, which adjust the lens of the eye for near or far vision. Reading and watching television in a dark room and working with glare on reading material and computer screens should be avoided.

Early diagnosis of eye and ear disorders allow one to benefit from early treatment that may prevent or at least retard further damage to vision and hearing. Routine eye exams use simple and relatively painless procedures to detect cataracts, glaucoma, SMD, changes in the blood vessels of the eye, and other disorders. Hearing tests can pinpoint specific areas of hearing loss, which may be partially compensated for with some sort of hearing aid. Early detection of hearing loss can also help one take action for the prevention of future hearing loss.

When asked what it is like to grow old, someone once replied, "Smear some Vaseline on your glasses and stuff some cotton in your cars, and you'll see what it's like." While no one has discovered the fountain of youth, there are a few things we can do to slow the physiological changes that occur as we age.

Loss of hearing and visual acuity are sometimes caused by artery disease (atherosclerosis), which is a long-term degenerative process affected by a number of variables, some of which are under our control. Regular exercise, avoiding cigarette smoke, and following a "heart-healthy" diet can help prevent atheroscierosis as well as other risk factors that contribute to it, including abdominal obesity, hypertension, and type II diabetes. Some researchers believe that the antioxidant nutrients, including vitamins C and E and vitamin A precursors called retinoids, may help prevent some of the age-related changes observed in the eyes, such as SMD. It is possible that these nutrients help buffer the eye from chronic UV damage. Some researchers believe many of the changes that occur as we age are caused by free-radical damage. Antioxidant nutrients may help reduce such damage.

Medical research suggests that zinc deficiency seems to increase one's risk for SMD. This does not mean that high levels of zinc will either correct or prevent SMD. Zinc is toxic at high doses, so it is best to meet one's recommended daily requirement for zinc by consuming foods supplying this nutrient, such as fish, chicken, red meat, whole grains, and legumes.