Download Amsler grid

What is the Amsler grid?
• Amsler grid: (AM-slur) test card, graph
paper-like grid used in detecting central
visual field distortion or defects
What is the Amsler grid?
• The Amsler grid is a small book of six
charts, although many offices use a tablet
style amsler grid that contains tear off
sheets that the patient can draw on and be
placed in their chart.
• The Amsler grid is a simple screening test
used to assess the macula (the center of
the retina).
• The Amsler grid consists of evenly spaced
horizontal and vertical lines printed on
black or white paper. A small dot is
located in the center of the grid for fixation.
While staring at the dot, the patient looks
for wavy lines and missing areas of the
grid.
• The test may be used diagnostically to
discover the presence and or location of
defects in the central field of vision. The
test is also frequently given to patients to
use at home to monitor macular
degeneration.
• The patient should see all the lines straight
and parallel with no broken, wavy,
distorted, or missing areas.
EXAMPLES: (NOT ACTUAL SIZE)
normal amsler
abnormal amsler
• the amsler grid is used for qualitative
vision evaluation of the central 20˚of
vision (10˚ on each side of fixation). the
amsler grid is a type of visual field
testing.
how is the amsler grid used?
• The Amsler grid should be held by the
patient at normal reading distance. This
test should be performed prior to the
instillation of any eyedrops.
• The patient should be using their best
correction for near. The test is
performed one eye at a time.
• The patient is asked to look at the dot
in the center of the grid. The purpose is
to see if the patient notes any
abnormalities in the grid while focusing
on the center dot
Some questions you may want to ask
the patient are…
• “While looking at the dot in the center,
can you see the whole grid?
• “Is any part missing or distorted?”
• “Are any of the lines wavy, bent or bowed?”
• You should have the patient draw any
abnormalities found. Make a note on the grid
paper of the patient’s name, date and which
eye.
• Grid should be placed in patient’s chart. Use
a separate sheet of grid paper for each eye. If
there are no abnormalities found in one or
both eye– you may note in chart WNL(within
normal limits) for the appropriate eye(s).
WHEN SHOULD THE AMSLER
GRID BE PERFORMED?
• The Amsler grid should be performed
when a patient presents with a decreased
visual acuity that is not. improved with
pinhole. Many times the patient will have a
chief complaint of distorted or strange
visual symptoms
WHAT EYE PROBLEMS DOES
THE AMSLER GRID DETECT?
• The Amsler grid is used to detect central
vision defects or distortions. The cause of
this type of defect or distortion is usually a
result of macular dysfunctions such as
macular degeneration, or other retinal
problems. Defects may also be attributed
to advanced glaucoma or neurological
problems
HISTORY OF THE AMSLER GRID
• Dr. Marc Amsler, a Swiss ophthalmologist
invented the Amsler grid. It appears that
he got the idea from patterns on a small
card with a grid pattern that Landolt
designed to place in the center of his
perimeter to test the macula. Some
problems with the perimeter cards were
difficulty of use, and not being able to test
for metamorphopsia.
THE GRID
• Each square measures 5 mm and when
the grids are held at 30 cm from the
patient each square subtends 1 degree on
the retina. The amsler grid is very simple.
The Amsler grid is available in a chart of 6
grids, as well as individual grids or tablets.
Commonly used grid
• The most common Amsler grid today is
white on black or black on white. In some
cases the black and white Amsler does not
detect early and subtle defects. Colored
grids can be used for various purposes.
Red lines on a black background are
useful for:
• Optic nerve problems
• Chiasmal disorders
• Toxic amblyopia
• Also available are blue-on-yellow, blue-onred and white-on-red background.
• Red Amsler grid screening may allow
practitioners to identify patients who are
more likely to have hydroxychloroquine(羟
氯喹[抗疟药,红斑狼疮抑制药]
) ocular toxicity.
•
• The appearance is due to a combination of
spreading and squeezing of the cones.
This condition is termed “Metamorphopsia”
• (视物变形症 )
• Patients with this defect may describe
objects as distorted.
• THE IMAGE BELOW IS AN EXAMPLE OF
“MICROPSIA”(视物显小症)- DISTORTED
VISION IN WHICH OBJECTS APPEAR
SMALLER THAN THEIR TRUE SIZE.
COMMON DEFECTS
• The grids below are examples of what a
person with macular degeneration might
see.
• This is an example of what a patient with
macular edema might see. This
appearance is attributed to the cones
being spread apart. The retinal image will
stimulate fewer cones and the lines of the
Amsler grid will appear smaller and seem
to bend away from the patient.
LESS COMMON DEFECTS
. the image on the left is an example of
“macropsia”(视物显大症 )- distorted vision in
which objects appear larger than normal.
• This is caused from the cones being forced
closer together, making the retinal image fall on
more cones than normal. This type of defect can
be created by a tumor.
• the image on the left is an example of a
central scotoma.
• This may be caused by Central Choroidal
Dystrophy, or CongenitalToxoplasmosis(弓
形体病 ). A scotoma may be “positive” or
“absolute”
• positive scotoma – non seeing area that
the patient is aware of as being dark or
black
• absolute scotoma – non seeing area
despite the size, color, or brightness of the
target
• the image on the left may be reported
by an advanced glaucoma patient. this
type of defect is an arcuate scotoma.
The End
• Click the Back button on your browser to
return to Online CE
• Thank You!