| As for any
organ of the body, good health provides the best
protection possible for your eyes. Stress, fatigue,
diet, drugs and alcohol all affect vision. The
combination of balanced nutrition, exercise and proper
care is essential to eye health. These factors are
critical to proper development of vision during infancy
and childhood, and important throughout life. Medical
evidence is mounting to show that good diet and a
healthy cardiovascular system contribute significantly
to healthy vision in later life. Nutrition
Essential vitamins, minerals and proteins must be
constantly available to the eye for it to function and
to keep nerve pathways open to the brain.
The circulatory system supplies the eye with
nutrients. Blood vessels feed the retina and other parts
of the eye. Even the lens and cornea, which are not
supplied directly with blood, are bathed by fluids that
deliver oxygen and other nutrients to these tissues.
- Vitamin A - In the retina, beneath the
light sensitive rods and cones, there is a layer of
colored compound called rhodopsin, or visual purple,
that bleaches when light strikes it. This chemical
reaction is responsible for the ability to see at
night. Vitamin A is a crucial part of the rhodopsin
compound.
As light strikes the visual purple, vitamin A
is lost and must be replenished immediately by
the circulatory system. If the mechanism is too
slow or there is not enough vitamin A stored in
the body, night vision diminishes. Dark leafy
vegetables, carrots and liver are rich sources
of this vitamin, as well as zinc and other
elements the body uses to synthesize it.
- Riboflavin - Riboflavin, also known as
vitamin B2, is not stored in the body but is amply
supplied by a well-balanced diet. Without it, the
eyes tear and look bloodshot. Milk and meat are
valuable sources of B2. Chronic deficiencies are
rare but are associated with alcohol abuse.
- Vitamin C - Vitamin C is needed at the
junction of the muscles that control eye movement
and the sclera and is present in all visual tissues.
- Vitamin D and Calcium - Serious
deficiencies of vitamin D and calcium may shorten
the eye during development, leading to
nearsightedness.
Tobacco, Alcohol and Drugs
Smoking is implicated in many eye disorders, just as in
diseases of all major systems of the body. Smoking is
the principal factor for age-related macular
degeneration.
Alcohol impairs vision. The eye is easily fooled into
mistaking alcohol for an essential nutrient. When too
much alcohol is in the body, the eye begins to make
visual mistakes. Long term, alcohol abuse is associated
with gradual loss of central vision.
Many drugs, medicinal and recreational, have side
effects on the eye. Impaired vision, dry eye, and pupil
dilation, increasing the risk of overexposure to light,
are a few examples.
Effects of the Sun
The eyes can get burned by the sun. The cornea, the lens
and the retina are all vulnerable to overexposure to
ultraviolet rays. Although the eye depends on light to
see, wavelengths below the color blue on the color
spectrum can harm the unprotected eye. These rays are
called ultraviolet (UV) light and are invisible to the
human eye. The negative effects of exposure accumulate
over time, throughout our entire lives. For this reason,
parents should start to protect their children's eyes
very early in life with UV-blocking sunglasses.
Both glasses and contact lenses can be treated to
filter out UV rays. Sunglasses that are untreated may,
in fact, be detrimental to the eyes. The pupil dilates
in response to lower light and actually exposes the eye
to more UV radiation.
Other Sources of UV Rays
Computers, television, video games and other electronic
monitors also emit UV rays. In addition to gradually
burning the eyes, they slow the rate of blinking, which
can be a significant hazard due to the decreased
lubrication of the surface of the eye.
Sitting at least 20 inches from computer screens and
3 feet from television or video game monitors can help
prevent damage. Increasing your rate of blinking and
using artificial tears are beneficial as well.
Sources
Nunnelley-Hamilton, EM, Whitney, En Sizer, FS.
Nutrition: Concepts and Controversies. 3rd
ed. St. Paul, MN: West Publishing, 1985. pp. 221-257 |
