| As people age, they inevitably experience vision changes. These
changes typically involve the eye itself, the surrounding muscle
and the central nervous system. The lens of the eye (usually clear
and soft in young people) grows increasingly opaque and rigid, and
the muscles surrounding the eye weaken.
Normal visual changes associated with aging include:
- reduced visual acuity;
- diminished ability to focus on objects;
- decreased color vision;
- the need for increased illumination.
Visual acuity is a measure of how clearly objects can be
seen. Normal visual acuity is 20/20. This means that a person standing
20 feet from an eye chart can correctly perceive a letter three-quarters
of an inch high. Since visual acuity usually decreases with age,
it is not unusual for an older person's acuity to measure 20/100.
Such an individual will need to be 20 feet from an object that a
person with normal visual acuity can see at a distance of 100 feet.
If no eye disease is present, visual acuity can usually be corrected
to normal or near normal with glasses or contact lenses.
Accommodation is the ability of the eye to focus clearly
on objects at different distances. As we age, the eye muscles become
more flaccid, making it difficult for the eye to shift its focus
from objects that are near to those that are distant. This problem
can usually be corrected with reading glasses, bifocals or sometimes
trifocals.
Color vision may also decrease as the lens of the eye grows
opaque. This decrease is most evident when a person tries to distinguish
closely-related colors, particularly in the blue and green color
families. For most people, color differentiation is rarely a problem.
Some people, however, may experience difficulty with depth perception
when, for example, stairs, walls and landings are the same color.
To avoid such problems, introduce contrasting colors in the environment
so that all objects such as entrances or light switches are clearly
visible.
Illumination needs are greater as we age because less light
is able to pass through the lens of the eye. Older people require
more light to perform detailed tasks. They may have trouble seeing
in dimly lit places, such as movie theaters or restaurants. In addition,
it may take longer for the eye to adjust to the change from darkness
to bright light and vice versa. Increasing the light levels and
focusing the light directly on the materials are usually effective
ways to resolve these problems. Changes in a person's vision may
signal an eye disorder unrelated to normal aging. Regular eye examinations
by an ophthalmologist or optometrist are important for all people
over 60. When eye diseases are diagnosed and treated early, the
risk of vision loss is greatly reduced or eliminated. Regular check-ups
also enable older people to have the best possible correction in
their glasses or contact lenses. Early diagnosis and treatment is
the single most important factor in preventing vision loss. |
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