Color vision is evaluated by the use of color plates
to assess the degree of color vision deficiency. No one is
truly color blind. Deficiency of color vision can be anywhere
from very mild to severe. It is a genetic condition that predominantly
occurs in males. Color vision can not be cured but it is helpful
to be aware of the abnormality to help with future planning.
The ability to judge depth or depth perception is
an ability that requires the two eyes to work together as
a team. The highest degree of depth perception is achieved
when both eyes accurately point and are simultaneously focused
on the object being looked at. Static depth perception is
when one is looking at objects that are stationary, for instance
when looking at objects in a room. Dynamic depth perception
is where one has to judge objects that are moving such as,
hitting or catching a baseball. Individuals who use only one
eye can still judge depth by using other cues to depth. Those
individuals have more difficulty with dynamic depth perception.
Tracking involves how well the individual
is able to follow a moving target in a smooth uninterrupted
motion. Another part of tracking involves the ability to move
the eyes accurately from one object to another. Individuals
who read well are able to move their eyes across the page
in a smooth controlled fashion. Difficulty in this area leads
to loss of place or skipping words or lines while reading.
Eye teaming (fusion) involves the
alignment of the two eyes and how well they work together
as a team. Difficulty in this area may result in inability
to sustain near point tasks or problems with depth perception.
Focusing ability allows
rapid and accurate shifts in visual tasks with instantaneous
clarity at differing distances, such as from desk to chalkboard
to teacher. Stamina of focusing affects how long one can read
before the eye's fatigue.
Alignment deals
with how accurately the eyes point at the target or object
being viewed. Misalignment can cause one's vision to be blurred
or to see double. This can occur on an occasional basis, or
can be constant. Ongoing double vision generally causes the
individual to adapt by suppressing the vision in one eye.
