by Andrew Pacholyk MS L.Ac ~
Nearsightedness, or myopia, is a vision problem experienced by up to about one-third of the population. Nearsighted people have difficulty reading highway signs and seeing other objects at a distance, but can see for up-close tasks such as reading or sewing.
Myopia Symptoms and Signs
Myopic people often have headaches or eyestrain, and might squint or feel fatigued when driving or playing sports. If you experience these symptoms while wearing your glasses or contact lenses, you may need a comprehensive eye examination as well as a new prescription.
What Causes Myopia?
Myopia occurs when the eyeball is slightly longer than usual from front to back. This causes light rays to focus at a point in front of the retina, rather than directly on its surface.
Nearsightedness runs in families and usually appears in childhood. This vision problem may stabilize at a certain point, although sometimes it worsens with age. This is known as myopic creep.
Hyperopia, or farsightedness, is a common vision problem, affecting about a fourth of the population. People with hyperopia can see distant objects very well, but have difficulty seeing objects that are up close.Hyperopia Symptoms and Signs
Farsighted people sometimes have headaches or eyestrain, and may squint or feel fatigued when performing work at close range. If you get these symptoms while wearing your glasses or contact lenses, you may need an eye exam and a new prescription.
What Causes Hyperopia?
This vision problem occurs when light rays entering the eye focus behind the retina, rather than directly on it. The eyeball of a farsighted person is shorter than normal.Many children are born with hyperopia, and some of them “outgrow” it as the eyeball lengthens with normal growth.
The hyperopic eye is shorter than normal. Incoming light focuses behind, instead of on, the retina. Near objects look blurry to farsighted people.
Sometimes people confuse hyperopia with presbyopia, which also is a difficulty in seeing up close, but has a different cause.
Those who lose the ability to focus on objects in the near range including the ability to read fine print. The 40-and-over crowd is finding that their arms are “growing shorter” as words become difficult to see up close, and they must hold small items at arm’s length in order to be able to view them clearly.Called presbyopia, this condition occurs as eyes gradually lose their ability to focus on objects in the near range. But boomers have more choices than their parents ever did when it comes to near vision correction.Reading glasses are a popular option. With all sorts of styles and colors, 40-somethings can have a pair for every room in the house. And they work great as an adjunct to contact lenses
For some, segmented spectacle lenses, or multifocals with lines, serve a specific purpose. Other presbyopes are flocking to no-line bifocals, or progressive lenses, in droves now that there’s no need to reveal to the world that one is a bifocal wearer. These lenses have more going for them than just good looks, though. They enable the wearer to see at all distances, from far away to up close, similar to the way that a person who doesn’t need vision correction focuses.
Although many people are not aware of it, macular degeneration, often called AMD or ARMD (for age-related macular degeneration), is the leading cause of blindness in the world. The eye-health organization Prevent Blindness America estimates that 13 million Americans have evidence of macular degeneration.The disease breaks down the macula, the light-sensitive part of the retina responsible for the sharp, direct vision needed to read or drive. Central vision, especially, is affected. Macular degeneration is diagnosed as either dry (atrophic) or wet (exudative). The dry form is more common than the wet, with about 90% of AMD patients diagnosed with dry AMD. The wet form of the disease usually leads to more serious vision loss. Macular degeneration is more common in people over age 65, and whites and females tend to get the disease more than their counterparts. Most cases of macular degeneration are related to aging. It also can occur as a side effect of some drugs, and it appears to run in families. Macular degeneration mainly affects central vision, causing “blind spots” directly ahead.
Macular Degeneration Symptoms and Signs
Macular degeneration can produce a slow or sudden painless loss of vision. If straight lines look wavy to you, your vision seems fuzzy, or there are shadowy areas in your central vision, you may be experiencing early signs of AMD.One way to tell if you are having these vision problems is to view an Amsler grid, which is a chart of black lines arranged in a graph pattern. Click here to see how an Amsler grid works. Often, an eyecare practitioner will detect early signs of macular degeneration before you experience symptoms. This usually is accomplished through a visual field screening, a brief test that measures your central vision. If the eyecare practitioner detects some defect in your central vision, such as distortion or blurriness, he or she will order a full visual field exam, a much longer test that provides more extensive information about your vision.
What Causes Macular Degeneration?
The exact causes of age-related macular degeneration are still unknown. The dry form of AMD may result from the aging and thinning of macular tissues, depositing of pigment in the macula, or a combination of the two processes. With wet AMD, new blood vessels grow beneath the retina and leak blood and fluid. This leakage causes retinal cells to die and creates blind spots in central vision. Factors that place you at a higher risk for AMD include having a family member with AMD, smoking, high blood pressure, farsightedness and obesity. Whites and females tend to get the disease more than their counterparts.
Many researchers and eye care practitioners believe that certain nutrients zinc, lutein, zeaxanthin and vitamins A, C and E help lower the risk for AMD or slow down the progression of dry AMD. Dietary fat may be a factor as well. A study published in the August 2001 issue of Archives of Ophthalmology found that consumption of omega-3 fatty acids, which are particularly prevalent in cold-water fish, had a protective effect against advanced macular degeneration. Meanwhile, consumption of omega-6 fatty acids, prevalent in vegetable oils, was associated with an increased risk.
Some cases of macular degeneration are side effects of toxic drugs such as Aralen (chloroquine, an anti-malarial drug) or phenothiazine, rather than age-related. Phenothiazine is a class of anti-psychotic drugs, including Thorazine (chlorpromazine, which is also used to treat nausea and vomiting, and intractable hiccups), Mellaril (thioridazine), Prolixin (fluphenazine), Trilafon (perphenazine) and Stelazine (trifluoperazine).