The eyes are the windows to our soul—and, sometimes, to the state of our general health. Vision abnormalities can be harbingers of other problems, including diabetes, brain tumors, multiple sclerosis, blood disorders, rheumatoid arthritis and lupus.

But trouble seeing can also indicate serious problems with, well, the eyes.

According to the American Foundation for the Blind, 6.5 million Americans over the age of 65 experience severe vision loss. Health officials predict that diseases of the eye, such as age-related macular degeneration (AMD), glaucoma and diabetic retinopathy will double as the nation's 78 million baby boomers reach retirement age and beyond.

One of the leading causes of impairment of vision in people over 50 is age-related macular degeneration, which is caused by the hardening of the arteries that nourish the retina. In 2004, the Archives of Ophthalmology estimated that 1.75 million U.S. residents show significant symptoms associated with AMD, with that number expected to grow to almost three million by 2020. Although AMD doesn’t often cause total blindness (peripheral vision is usually not affected), it can cause severe vision loss.

Sarasota resident Furman Arthur knows all about this devastating condition. Three years ago, he noticed that the vision in his right eye was more blurry than usual. In his early 80s, he chalked it up to old age. When it started seriously interfering with his reading and writing, Arthur, a former public relations director at New College and a journalist who still practices his craft, knew it was time to see his eye doctor. That doctor sent him to a retina specialist.

By the time Arthur saw the specialist, he had lost most of his central vision in his right eye. He still had peripheral vision, but anything in the center of his vision was blurred and mostly unrecognizable. The specialist told him what he feared: The macula in his right eye was showing signs of deterioration.

But let’s back up a minute. What the heck is the macula, anyway?

The macula is located in the center of the retina, says Dr. Harry Grabow, founder, medical director and chief surgeon of the Sarasota Cataract & Laser Institute, “and is the part of the eye used for focusing on detailed vision, especially reading and driving. One of the first symptoms of macular degeneration is difficulty reading very small print, especially newspaper print.” Patients complain, he says, of seeing a blank hole in the center of their vision.

“Macular degeneration happens when the arteries that nourish the retina begin to harden,” says Grabow. “The tissue of the retina becomes deprived of the oxygen and nutrients that keep it healthy. As a result, the central vision deteriorates.”

There are two types of macular degeneration. The wet type is the most aggressive form and occurs when new blood vessels grow under the macula in an attempt to carry much-needed oxygen to the area. “These vessels break easily, causing bleeding and damage to the surrounding tissue,” says Grabow. Statistics show that about 10 percent of patients who suffer from macular degeneration have the wet type. Arthur happens to be one of these people.

The dry type of AMD is more common and generally results in less severe loss of vision. It can progress to wet, so if you’re diagnosed with dry AMD, you’ll be advised to have your eyes examined at least twice a year.

What causes this unpleasant condition and how can we prevent it? While scientists still haven’t come up with one determining cause, the condition is aggravated by a variety of factors, including age, dietary habits and overexposure to sunlight. Smokers are found to have higher incidences of it. Recent research by Duke University and other research facilities shows that genetics play a role. If you have a family member with AMD, it’s a good idea to have your eyes checked at least once a year after 50. Obesity, lighter eye color, and high blood pressure are also seen as factors that point to a predisposition to AMD.

As for symptoms, says Grabow, the disease takes its time, and the process is usually slow and relatively painless. Most commonly, patients complain of experiencing fuzzy or distorted vision. They also report difficulty in reading. One way to tell if you’re experiencing AMD is to take an Amsler grid test. This is a chart of black lines arranged in a graph pattern that’s used to monitor vision loss.

We all want to be able to read and drive well into our 80s. If we can’t prevent the condition, what can we do to cure it?

There is still no outright treatment that cures either type of AMD. That said, there is a new FDA-approved drug being used to stop abnormal blood vessel growth for patients suffering from the wet type of macular degeneration, says Dr. Keye L. Wong of the Sarasota Retina Institute.