An Eye Full - A Look At Ophthalmology Terms
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
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
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
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
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 eyecare 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).
Andrew Pacholyk, MS. L.Ac