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CONFRONTATION TEST &AMSLER GRID

Instructor: Michael Patrick Coleman, COT & ABOC

What is a “visual field” and why does it matter?

Definition: • Visual field: The entire area that can be seen

when eye is looking straight ahead @ fixed pointWhy does it matter?• If a person is experiencing a “shrinking” visual

field or a “distorted” visual field, they have a problem. We want to help them before the problem robs them of any more visual loss.

Peripheral vs. Central fields which test does what?• A normal visual field extends out as far as:

– 100° temporally– 60° nasally– 60° superiorly– 70° inferiorly

Peripheral vs. Central fields–which test does what? (cont.)

* A physiologic scotoma (a blind spot) exists 15°temporally in VF; it is due to the optic nerve (nasal retina)* The average blind spot is 7.5° in diameter & vertically centered 1.5° below the horizontal meridian

Peripheral vs. Central fields–which test does what? (cont.) Confrontation Field TestIN A NUTSHELL:1. The examiner & Pt face each other, eye level2. Examiner asks Pt to look into his/her open eye3. Examiner presents one or two fingers in Pt’s

peripheral Visual Field (VF)4. Pt responds when he/she can see the target5. All four “quadrants” of an eye are tested (ST, IT,

SN, & IN)6. Once done w/one eye, test is repeated for the

other eye

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Confrontation Field Test (cont.)

• Test distance?– ARMS LENGTH DISTANCE (about 24 inches)

• Instructions to patient?– “Look @ my open eye ONLY”– “Tell me WHEN you see my fingers and HOW MANY I

am holding up”

• Comparing the patient’s perception to the examiner’s perceptions?– You (the examiner) are the “NORM”; if Pt sees your

fingers when YOU see your fingers, they are “WNL”; if you have to keep moving closer to central fixation before Pt responds, they are “ONL”

Confrontation Field Test (cont.)

• Recording the results?–WNL (within normal limits) if Pt results are

comparable to yours–ONL (outside normal limits) if Pt results are

‘worse’ than your own perceptions• If ONL, describe problem; For EXAMPLE:

– “OD constricted in ST and IT fields”– “OU constricted in all quadrants”

Amsler Grid Test **

• Test chart• Recording chart• Additional charts• Administering the test

–Test distance–Degree of field measured–Questions to ask & in

what order–Recording the results

Amsler Grid Test (cont.)

• Amsler Grid invented by Dr. Marc Amsler (Swiss ophthalmologist)

• The AMSLER GRID “TEST” is a booklet with six (6) different charts in it

• Purpose is to ASSESS THE MACULAR AREA, so it is most commonly used to check patients with Macular Degeneration (wet or dry)

Amsler Grid: Test Chart Amsler Grid: Recording Chart

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Amsler Grid: Additional ChartsRed lines on black back-ground? Helpful for:• Optic nerve issues• Chiasm disorders• Toxic amblyopia• Hydroxychloroquine

ocular toxicity

Amsler Grid: Additional Charts (cont.)Also available are charts with…• Blue lines on a yellow background• Blue lines on a red background

•White lines on a red background

• When would you use them?–Whenever your doctor SAYS to use them!

Amsler Grid: Administering the Test• Test distance = 30cm (or 12 inches)• Pt wears their NEAR VISION CORRECTION

– BiFocal or PAL? Have Pt hold glasses up so they can look at GRID through the near correction

• Degree of field measured = 10 degrees – Have you ever read that it tests “20 degrees”? That is

WRONG!– We measure Visual Field from how many degrees we

are from the fixation point; the AMSLER GRID only tests out to 10 degrees from the center of fixation

– (If it tested out to “20 degrees”, as claimed, the ‘physiological blind spot’ would be detected!)

Amsler Grid: Administering the Test (cont.)

• Another way to “prove” that the AMSLER GRID only tests out to 10 degrees is this…–Each square of the grid

measures 5mm–When the Amsler Grid is

held 30cm from eye…–…each square “subtends”

1 degree on the retina– Let’s count the ‘squares’,

shall we…

Amsler Grid: Administering the Test (cont.)

Questions to ask & in what order1. “While looking at the center dot, can you see the

FOUR CORNERS and FOUR SIDES of the grid?”2. “While looking at the center dot, can you see

there are lines going UP & DOWN and SIDE TO SIDE in the chart?”

3. “Are the lines straight & clear, or do you see any WAVINESS, DISTORTION, or MISSING AREAS”

Amsler Grid: Administering the Test (cont.)

• A Pt indicating the chart looks like this most likely has Macular Degeneration

• Distortion of the vision is called “Metamorphopsia”• It’s caused by the cones of the retina being spread

apart one place & squeezed together in others

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Amsler Grid: Administering the Test (cont.)Recording the results• If patient saw the chart fine (no problems) you

can record “WNL” in the medical record• If there were problems, You should have the

patient draw any abnormalities found. Make a note on the grid paper of the:–Pt’s name, date & which eye the chart

represents–The Amsler Grid the pt marked on should be

placed in Pt’s chart–Use a separate Amsler Grid for each eye