Using an Amsler Grid For Macular Testing at Home

By Omar Ahmad, MD

Many patients are given an Amlser grid by their eye doctor to use at home. This is used to help catch visual disturbances by the patient at home. The test is particularly effective for macular conditions. The macula is a specialized part of the retina that gives one their central vision. Conditions such as age related macular degeneration, epi-retinal membranes, central serous retinopathy, and diabetic macular edema can affect the macula.

What Is the Amsler Grid?

The test is a series of perpendicular vertical and horizontal lines with a dot in the center of the grid. There are various versions of the grid with different colored lines and backgrounds. There are also various sizes, ranging from business card size to full size copy paper. Even the smallest grid will be effective if used properly, but a larger grid will be easier to use.

When a patient looks at the grid, that pattern is essentially projected onto the macula. If there are defects in the macula, these will be apparent as defects in this projected image. There is nothing magic about the Amsler grid. It just forces a patient to test each eye independently and the pattern of the grid is fine enough that defects in the vision may be caught earlier than they may be otherwise.

If there is a defect in a patient's central vision that prevents them from seeing someone's entire face, this would be obvious even without the use of an Amsler grid. By using the grid routinely, that defect may have been caught much earlier and before it occupied such a large part of the central vision.

When To Do the Test

Testing each eye with an Amsler grid is very quick and patients are encouraged to use the test daily. In addition, if a patient feels there may be a problem with their sight, the test should be performed. This may help determine if the problem is on one eye or both and if there is a possible macular problem.

How To Do the Test

Use your regular reading glasses.
Hold or stand 14 inches away from the grid.
Cover one eye with your hand.
Stare at the dot in the center. Do not let your eye drift from the center dot.
Even while looking at the dot, you will still see the grid pattern.
Look for
Any of the straight lines appear wavy or bent,
Any of the boxes differ in size or shape from the others, or
Any of the lines are missing, blurry or discolored.
Repeat the test while covering the other eye.

If you do see a defect, mark on the grid where the defect is.

Some patients already have some defects in one eye. In this case, the grid can be used to monitor change from their baseline. Mark out where the defects are with a pen and if there are new ones, contact your eye doctor. If there are known significant differences between the two eyes, it is advised to have two copies of the Amsler grid, marked RIGHT eye and LEFT eye. True retinal problems will not go away with a blink, use of artificial tears, or change in glasses. They will usually persist at all times until the retinal problem is addressed.

What To Do If You See a Change on Your Amsler Grid

The test is very simple to do, but it is quite effective at catching macular disease. If you have performed the test properly and there are defects on the grid, you should contact your eye doctor right away to schedule an evaluation.