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- Eye Care Treatment
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Visual Disability Scale
20/20: This is considered standard normal vision.
20/25 to 20/65: Subnormal vision, but not seriously impaired. Those
below 20/45 have difficulty reading a newspaper, but most can hold
it closer to their face and still read with good light. Many states
will license people to drive with visual acuity as low as 20/60, but
most such drivers will carry restricted licenses. Telescopic glasses
allow all of this group to drive as long as their state permits it
and if they do not also have serious field loss. These people have
excellent object and travel vision, except for those who have lost
considerable field vision as well as visual acuity.
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20/70: Mildly impaired. This is the point
where people really begin to feel handicapped. Reading
newspapers is very difficult without magnification, and most
states refuse to license persons to drive with a visual
acuity this low unless they are equipped with telescopic
glasses. Object and travel vision are still excellent,
except for those who have lost field vision as well.
20/75 to 20/200: Moderately impaired. This group can still
function as sighted in most regards with the use of
low-vision aids. Object vision for this group is poorer, but
it is still adequate for almost all activities. These people
can see the car but may have trouble identifying its make
and model. Recognizing friends may be difficult, but they
see the person. Travel vision is still quite good unless
there is also field vision loss. |
Reading is the primary problem for this group,
but good equipment and training eliminate this problem. People
in this group can be equipped and trained to read using numerous
low-vision aids. All members of this group should be able to
drive with telescopic glasses unless there is also serious
peripheral-vision loss, or other limiting factors.
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20/200 to 20/800: Seriously impaired, but
still with travel vision and reduced but useful object
vision. People in this group can read with low-vision aids
of various kinds. Those below 20/500 might consider learning
Braille, but even then it certainly isn't mandatory. These
people will not be able to drive, even with telescopic
glasses. Object vision diminishes but is still useful.
Travel vision is still adequate, although those at the lower
end of the scale may sometimes trip over curbs. Crossing
streets can be hazardous for people at the lower end of this
scale because they cannot see distant oncoming cars.
20/800 to 20/1200: Severely impaired. At this level of
visual acuity a person loses travel vision. People suffering
a loss of peripheral vision may find a white cane useful or
even necessary before this point is reached, but at this
stage, use of the white cane becomes necessary, regardless
of the cause of vision loss. |
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Some in this group are able to use very strong magnifiers to read
large print. A +50 diopter lens will give almost all in this group the ability
to read textbook-size print.
20/1200 to 20/6000: Very severely impaired. Many doctors reject the
use of visual acuity figures this low. While it is true that letter
sizes larger than 700 do not exist on test charts, there are
mathematical equivalents. Doctors categorize this level as the
ability to see a hand moving one foot away, without the ability to
count fingers. People in the 20/1200 to 20/6000 group are dependent
on the white cane or a guide dog for independent mobility. A video
visual aid for reading print is the aid of choice and the only aid
that provides visual access to print. Voice synthesizers are
available that convert print into speech. Persons in this group are
legitimate users of such equipment.
This group has little object vision, but as long as there is any
light perception, that vision is useful. For example, a man walking
down the street with his white cane sees two shadows ahead. He sees
light between the two objects. He probably can't tell what the
objects are, but he knows there is space enough between them for him
to pass through. |
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