An Amsler grid, also known as an Amsler grid test, is a tool you can use at home to test your eyes for vision problems. It’s commonly used to test for signs of age-related macular degeneration (AMD). It’s also used to test certain eye functions before cataract surgery.
This tool is named after Marc Amsler, who lived from 1891 to 1968. He was a Swiss ophthalmologist, or eye doctor, who described the tool in 1947.
A basic Amsler grid is a 10x10-centimeter square filled with evenly spaced straight lines in a grid pattern. The lines form very small squares that measure 5 millimeters on each side. There’s a dot to mark the center. The basic grid has black lines on a white background, but variations exist.
What Is AMD?
It’s an eye condition that affects your central vision. This is the type of vision you use to see details right in front of you. For example, you use your central vision when threading a needle, reading a book, or recognizing a face.
The condition is caused by age-related damage to your macula, which is part of your retina. Your retina is the light-sensitive tissue at the back of your eye. AMD is the leading cause of severe vision loss in older adults.
The vision loss is progressive. It happens quickly for some people and gets worse slowly in others. There are two main kinds of AMD: dry and wet. Dry AMD can have early, intermediate, and late stages. Wet AMD is a more severe condition and always counts as late-stage AMD. Dry AMD can progress to wet AMD.
Dry AMD tends to get worse more slowly than wet AMD. With dry AMD, your vision loss gets worse over years.
This means that it’s incredibly important for you to monitor your vision as much as you can once you’re at risk for – or have begun to develop – AMD. You’re more at risk if you:
- Are older than 55
- Have a family history of AMD
- Are White
- Smoke tobacco products
Why Do I Need an Amsler Grid Test?
If you’re already having symptoms of macular degeneration, such as blank spots in your vision or trouble seeing in low light, an Amsler grid test can help you monitor your vision over time.
If you have dry AMD, this test can help you catch symptoms of diminishing sight even if you don’t have other symptoms.
The test is not a stand-in for regular eye checkups. An eye doctor can look much more in-depth at your eye health and see signs that you might be missing.
How Can an Amsler Grid Help With AMD?
An Amsler grid test is able to test your vision for many of the signs of intermediate and late-stage age-related macular degeneration. When your vision is normal, you should be able to see all areas on the grid, and all lines should appear straight.
If you have AMD, you could notice defects on the grid. These can include:
- Blank spots
- Warping lines that converge at a spot
- Wavy lines
- Blurriness in parts of the grid
It’s a portable test that you’re meant to use every day at home. You can use it to test for the start of any of these problems or to see if your vision is getting worse. This is particularly helpful if your eye doctor has diagnosed you with early-stage dry AMD and wants to monitor the progression of your condition.
The main goal of the test is to decrease the time between the start of your vision problems and the beginning of treatment. The hope is that using the grid will slow down or prevent the progression of your vision loss.
How Do You Use an Amsler Grid?
If your doctor has told you to use an Amsler grid at home, then it’s important that you follow their instructions precisely and do the test the same way every time. This will increase the accuracy of your results.
To use an Amsler grid, you should:
- Find a place with good lighting.
- Wear any glasses or contacts that you need to see up close.
- Hold the grid at a normal reading distance, or about 12 to 15 inches in front of your face. It’s important to keep it at about the same distance every time you use it.
- Cover one eye.
- Focus directly on the center dot with your open eye.
- Without shifting your focus, use your side vision to see if there are any dark or blank points on the grid. Take note if any of the lines appear wavy or seem to come together anywhere. Check to be sure you can see all four corners of the grid and that all grid lines are clear and solid (not blurred or faded).
- Mark the location of any defects that you see on the chart.
- Repeat the process with your other eye.
Your eye doctor may be able to give you an Amsler grid to use at home, or you can find one online to print. The basic grid just requires black ink and normal computer paper.
Variations on this grid exist. Some include diagonal lines to help you focus. Others use red lines for the grid, which may increase the sensitivity of the test. Your eye doctor may have you try multiple versions. Ask your eye doctor for advice on the best type of grid to use at home.
How often should I use an Amsler grid?
If you have macular degeneration or a related condition, your doctor will likely recommend you use an Amsler grid every day. By using it daily, you can see changes in your vision and address them before they turn into permanent vision loss.
Amsler Grid Distortions
When your vision has changed because of an eye condition, you’ll see certain abnormalities when you look at an Amsler grid.
Blank spots. There may be areas of the grid that disappear completely from your vision.
Warped or wavy lines that come together. The boxes on the grid should be uniform in size and shape. If the lines aren’t straight or the boxes change from one part of the grid to another, that’s a sign of vision changes.
Blurriness in parts of the grid. The lines should look sharp and distinct. Lines that look smudged or out of focus are a sign of a problem.
When Should You Talk to Your Eye Doctor?
An Amsler grid is not a replacement for regular eye exams. But Amsler grid results can show that you need to see your eye doctor as soon as possible. Contact your doctor if you notice any new abnormalities while using the Amsler grid. You should also let them know if your vision seems to be getting worse.
Make sure that you know how to properly use the grid before trying it at home. Proper patient education is key to getting the most benefits from Amsler grids for macular degeneration.
