For near vision, 14/14 (35/35) is normal, with
14 in. (36 cm) being the normal
distance for reading. If the second number is greater than 14 (14/20, for
example, or 35/50), it means that you have reduced near vision. You have to be
14 in. (36 cm) away to read
print that people with normal near vision can read from
20 in. (51 cm).
Jaeger (J) number is another way to rate your near vision. The J number relates
to the size of text you could read on the Jaeger chart. The J number goes up as
the print size of the text you read goes up. The higher the J number, the worse
your near vision. The number can range from J1 to J16. For example:
- J1 means that you could read the smallest
text on the chart and that you have 20/15 vision.
- J2 means the line
of text you were able to read had larger print than J1, and your vision is
- J3 means the line of text you were able to read had larger
print than J1 and J2, and your vision is 20/40.
Visual acuity tests usually take about 5 to 10
The health professional tests your eyes
with different lenses until the lens that corrects your vision the best
(sometimes better than 20/20 or 6/6) is found. The result of a refraction test
determines your prescription eyeglass or contact lens strength.
refraction test takes 5 to 30 minutes (30 minutes if dilating drops are used).
Visual field test
Normally, a person's visual
field forms a rough circle with a natural blind spot. If your vision is normal,
you should be able to see objects clearly throughout the entire visual field
except for the area with the natural blind spot. When you are using both eyes
to see, the blind spots do not interfere with your vision.
have vision loss in certain areas of the visual field if you are not able to
- Test objects during tangent screen
- Movements or light flashes during perimetry
Abnormal results during Amsler grid testing
- Not being able to see the black dot at the
center of the grid.
- Not being able to see all four edges of the
- Having blank spots or dark spots on the grid (other than the
black dot at the center).
- Seeing lines that look wavy or
Gaps in different parts of the visual field may have many
causes, including eye diseases (such as glaucoma and macular degeneration) or
nervous system problems (such as stroke). If results on any of the visual field
tests are abnormal, you will need further tests to determine the cause.