Friday, November 18, 2016

The sensory Effects of Aging and find out if you're at risk. - 5 .

Eyesight and Aging

Are you holding your newspaper at arm's length? 
Squinting at documents to see the fine print? 
Do you need more light to see clearly? 
Each passing decade brings changes that weaken eyesight, including the slow loss of ability to focus on close objects or small print.

Presbyopia, the most common reason why you and your peers need reading glasses, is characterized by decreasing ability to focus on nearby objects. This condition typically shows up around age 40 but often develops for decades before that.
Some of the age-related eye changes are obvious, while others go undetected until vision is limited in some way. For example, the tissues surrounding eyes lose their tone, and fat is lost, too, which results in droopy upper eyelids and the turning outward or inward of the lower lid.
On the other hand, cataracts, which cloud your vision by keeping the light from getting through the clear lens of the eye, are barely detectable because they form at a snail's pace, are painless, and don't result in any redness or tearing in the eye. Over the years, the iris, the colored part of your eyeball, loses flexibility.
Your pupils -- the black holes in the iris that respond to light -- get smaller, and the lenses start to accumulate yellow substances, possibly as a result of exposure to sunlight. These changes predispose you to glaucoma, the product of excessive pressure inside your eyeball, which can lead to vision loss and blindness. No one knows the cause of glaucoma, but it is more prevalent in older people, African-Americans, and in those with a family history of the disease.
Glaucoma is basically symptom-free, often until it is too late. Once glaucoma has damaged the optic nerve, which transmits visual information from the eye to the brain, you're past the point of treatment. That's why The Glaucoma Foundation recommends testing for glaucoma every four years until age 45 and every two years after that. Get tested every two years regardless of age if:
  • you're of African-American descent
  • glaucoma runs in your family
  • you are nearsighted
  • you have high blood pressure
  • you've been using cortisone long-term
Decreased blood flow to the retina, the paper-thin tissue lining the back of your eyeball, can lead to macular degeneration. Macular degeneration destroys sharp, central vision.

Aging and Taste

You can thank your nose for your sense of taste, despite the thousands of taste buds populating your tongue: They can only detect a mere four out of thousands of possible flavors in foods.
The tongue recognizes only sweet, salty, bitter, and sour tastes. That's why enjoying food is limited without a healthy sense of smell. When you chew food and drink beverages, their aromas are released in your mouth.
Saliva dissolves flavor-producing substances in food and drink that make contact with your tongue's taste buds. More importantly, dissolved flavor compounds waft up the back of your throat, making their way to receptor cells in your nose. From there, nerves transmit flavor messages to the brain, allowing you to perceive and enjoy them.
If you're having trouble savoring the flavor of food, blame it on a lessened sense of smell. Time dulls your sense of smell, but not usually until you reach age 60, and then it varies from person to person. About half of adults over the age of 65 suffer from some diminished sense of smell. On the other hand, your sense of taste for sweet, salty, bitter, and sour foods may be remarkably intact until you're well into your seventies.
A zinc deficiency can also cause a decreased sense of taste. Zinc supplementation can help restore it if you do have a deficiency. Infections threaten sense of smell and, as a result, your ability to enjoy food. Some of the damage from the flu, colds, or hepatitis can be permanent. More often than not, acute illnesses, including sinus infections and seasonal allergies, block aromas from the receptor cells that relay flavor information to the brain.
As a result, you don't have as much capacity to savor the flavors of food. The pills you take every day to control medical conditions such as high blood pressure and arthritis can affect sense of taste, mainly by affecting the areas of the brain where you perceive flavors. Chemotherapy drugs and head and neck radiation also threaten flavor perception, sometimes permanently.

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