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Seeing & Believing

Feb. 28, 2012
 

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One of the greatest blessings we humans are given is the ability to see. It’s almost incomprehensible that our two eyes can take in so much of the world, and then translate it into images that we can perceive with our minds.

Unfortunately, there are many things that can go wrong with one’s vision, but many of them are avoidable or treatable. Today, we know more about the eye than ever before, and our options for preserving vision have improved accordingly.

The human eye is truly a miracle of biology. All the parts have to work correctly in order for the eye to take in light and transmit this energy to the brain. The light enters the eye through the cornea, which is the clear surface of the eye’s orb. The pupil is the actual opening that lets the light through; it narrows and widens according to the amount of available light.

The light then passes through the lens, which further refracts and fine-tunes that light into an image and onto the retina. The retina is a tissue membrane that acts like film in a camera, with photosensitive cells that receive the focused light from the lens and then transmit it to the brain via the optic nerve. Indeed, it would be most correct to say that the brain “sees,” while the eye provides the image for the brain to see.

The most common vision problems are caused by refractive errors, or mistakes in the way that the eye focuses light on the retina. These can include nearsightedness, or myopia, in which the eye has trouble seeing distant objects; farsightedness, where the eye struggles to see objects close up; astigmatism, where images appear blurry or stretched because of an uneven transmission of light onto the retina; and presbyopia, which is similar to farsightedness in that the eye has trouble focusing on smaller objects.

Presbyopia is an age-related condition that typically affects those over 35. Nearsightedness, farsightedness and astigmatism can strike at any age.

“With young children, you need to be alert to any problems they might have seeing the blackboard at school,” said Dr. Troy Newman, board-certified ophthalmologist at Jackson Eye Associates. “Older kids and adults can tell pretty easily if they are having vision issues that need to be checked.”

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More serious eye disorders include glaucoma, caused by an excess of fluid pressure in the eye that damages the optic nerve, and diabetic eye disease, a series of complications from diabetes. Any of these can lead to the complete loss of sight, or blindness; often there are few or no warning signs.

“Glaucoma is a silent, progressive disease that often presents no symptoms,” Newman said. “People should be aware of any family history with the disease, and after 40 they should get a good comprehensive exam.”

Another serious eye disorder is the development of cataracts, a clouding of the eye lens.

“Everyone who lives long enough will develop cataracts to some degree,” Newman said. “It’s part of the normal aging process, but certain risk factors can make it strike earlier and more severely.

“Smokers and those who take steroid medications, or those who suffer from inflammatory conditions like rheumatoid arthritis, are at elevated risk.”

The best way to determine if you have one of these disorders (especially the more serious ones like glaucoma or diabetic eye disease) is to get a comprehensive dilated eye examination from an eye care professional. In this exam, the examiner will place drops in your eye to widen the pupil, and then will check the back of your eye for problems. He or she will also test the effects of eye pressure (which can help detect glaucoma) and check your ability to see at different distances.

The options for corrective eye procedures today are far beyond what was available just a few years ago. The best known of these revolutionary options is LASIK surgery. LASIK stands for Laser-Assisted In Situ Keratomileusis and entails a permanent restructuring of the cornea by way of a fine laser. LASIK surgery can reduce or eliminate the need for glasses or contact lenses; however, it is not for everyone. It’s important to consult with a qualified ophthalmologist before deciding whether LASIK is the right option for you.

“LASIK is very safe with a very low chance of complications, but it’s only for certain people,” said Dr. Heather Hancock, associate professor of ophthalmology at University Medical Center. “It will help those with moderate nearsightedness and no major problems. For those with more serious issues like macular degeneration, LASIK really won’t help.

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“However, the treatment options for even those people are much better than they were a few years ago. We can often save the sight of those who, until recently, would have lost it.”

“Patients with the ‘wet’ type of macular degeneration (in which fluid leakage or bleeding in the eye causes damage to the photoreceptors in the retina and permanent vision loss) can now take anti-cancer drugs called Avastin or Lucentis,” said Dr. Connie McCaa of the LASIK Laser Eye Center. “These drugs restrict the growth of abnormal blood vessels in the eye and have proven to be extremely effective.

“For those with ‘dry’ macular degeneration (where the retinal pigment epithelial layer below the retina atrophies), the only option is to increase one’s intake of zinc and antioxidants. This has been shown to slow the progress of dry MD.”

Cataract patients also have better options today.

“Cataract surgery has evolved to where it is relatively low-risk, with quicker recovery and better visual outcomes,” Newman said. “It’s an outpatient procedure with minimal anesthesia.”

There are many things that you can do every day to help preserve and protect your own vision:

• Get a regular comprehensive dilated eye examination. “For those under 30 with no major vision problems, an exam every five years is probably sufficient,” Hancock said. “For others, it’s best to get an exam once per year if possible.”

• Eat a well-balanced diet. Fruits and vegetables in particular, as well as fish, are rich in nutrients that strengthen the eyes. “More and more research has shown that the antioxidants in green vegetables and the fatty acids in fish can help ward off cataracts or macular degeneration,” Hancock said. “Supplements that contain these nutrients are good, but eating the actual foods is best. We still don’t fully understand how they work to support healthy vision.”

• Avoid obesity. Unhealthy weight gain can lead to diabetes, which can cause complications like glaucoma.

• Protect your eyes. Sunglasses will shield your eyes from dangerous ultraviolet rays. If you play sports or do manual labor, protective eyewear can guard against injury.

• Don’t smoke. Smoking isn’t just bad for your lungs. The carcinogens in tobacco products can lead to an increased risk for vision-related problems, including cataracts and glaucoma.