Field Eye Testing Methods

Visual field tests measure an individual's central and side vision. The tests are helpful in detecting signs of glaucoma, optic nerve disease, and eyelid problems such as drooping. Testing the visual pathways to the brain allows medical professionals to find tumors and macular diseases. All eye tests are done one eye at a time. There are several types of testing methods and they are divided into several different categories.

Confrontational Test

• For a quick and basic check, a confrontational visual field exam will help to determine the total area in which objects can be seen. The test is performed by the examiner standing directly in front of the patient. Patients must cover one eye while staring directly ahead with the other. Examiners request the patient to tell when their hand is visible in the patient's field of vision.

Perimetry Test

• The perimetry test is commonly used to test for glaucoma and measures all areas of eyesight. Testing begins once the patient sits and stares into an instrument known as a perimeter. While staring at the center of the bowl, the patient must press a button every time a flash occurs. Since flashes are recorded, a printout shows the examiner areas in which the patient could not see. All of the areas noted are referred to as areas of vision loss. Side vision loss is an early sign of glaucoma.

Tangent Screen Testing

• The tangent screen method is an effective way to test vision. When compared to the confrontational method, it is more sensitive. Patients should wear their prescription glasses during the exam. All of the plotting is marked from non-seeing to seeing. Blind spots are usually plotted first. The screen targets consist of black felt backgrounds with circular stitching every five degrees.