The aim of a visual field test is to determine how far in their periphery a person can see in all directions when focusing on a central target. This is called perimetry, and it is the process of measuring the extent of what you see and cannot see in your visual field.

How is visual field testing conducted?

The doctor will place your prescription into the machine while you are looking into it. Only one eye is tested at a time. A patch is placed over one eye, and then you will look at the central fixation target with the other eye. There is typically going to be a yellow light with different flashes appearing on the side of your vision. The intensity and location of these flashes will vary, but essentially, whenever you see the light, you will click the button, not looking directly at the bright lights that are flashing on the side of your vision. You'll have to keep your eyes fixed on the central yellow target, and you'll have to click the button anytime a flash of light appears. It takes about five minutes to complete this test. Then it will print out a report showing what your visual field looks like.

Is visual field testing important?

This test is vital because it allows your eye doctor to diagnose and monitor certain conditions. In visual field testing, specific conditions produce various and very specific patterns. In glaucoma, for example, there may be specific patterns they see on this visual field report that can help determine if you have glaucoma. What is so important about a visual field test is that it not only helps diagnose, but it also helps your eye doctor track the progression of the disease. Furthermore, it shows if the patient has any sort of functional vision loss.

The frequency of testing is highly dependent on your condition or risk category. For example someone with glaucoma who exhibits visual field loss may be told to come in more frequently than a patient with family history and risk factors for glaucoma but no actual peripheral vision loss.

What conditions can be diagnosed using visual field testing?

An eye doctor can use this tool to better diagnose and treat patients with many different diseases, one of the most common is glaucoma, however the visual field test is also used for other conditions besides glaucoma.

They may use a more specific type of visual field test if you have any macular issues that are more sensitive to the central portions of the back part of the eye and check if there is any functional loss in the central part of the back part of your eye.

They can also test for various neurological issues and in those types of tests, it measures more peripheral points. Likewise, if you are suffering from any sort of brain disorders such as stroke, concussion, or tumor growth, an examination of your visual field may indicate these conditions and require further testing, such as an MRI or CT scan. Visual field test provides them with very useful information about your overall visual abilities.