Amsler's test is performed by having the patient look at a piece of paper with boxes/a grid of a particular size, and then having them describe the shape of the boxes.
In the case of diseases with swelling in the retina (such as wet AMD), the boxes may appear as if they were formed by curved lines, so-called metamorphopsia.
If there is vision loss in the visual field in the vicinity of the central visual field, the boxes could appear to be missing in on or more areas of the grid.
How to perform the test
- Place the patient in a comfortable reading distance to the grid (often around 25-35 cm/12-14 inches)
- Ask the patient to wear their normal reading glasses
- Ask the patient to cover on of their eyes, and look at the black spot in the middle of the grid with the other eye
- The eye must focus/fixate on the spot the entire time
- All lines should appear straight, and all boxes should appear to have the same size
- Complete the test for each eye
Save the card and test the vision regularly (yearly when the patient is above 45 years, or as often as monthly if the patient is above 65 years old).
If parts of the card/grid seems to appear hazy, distorted or in any other way irregular, the patient should contact an ophthalmologist as soon as possible to have their vision and retina checked.
Example of the appearance of an Amsler's grid for patients with AMD
The left image shows how the Amsler's grid appears for a patient with no AMD symptoms. The right images shows an example of how the Amsler's grid might appear for a patient with symptoms of AMD.