North Texas Eye Care Equipment
Humphrey Visual Field
The Humphrey FDT (visual fields) uses frequency doubling technology to provide a clinically verified way to detect early visual field loss. Visual field testing is a basic element in the standard of care for glaucoma management, previous retinal injuries, papilledema, ocular hypertension, and macular degeneration. The patient 's vision will need to be corrected while completing the test. If you did not bring your contact lenses or glasses, when can provide a trial frame with your best corrected prescription (the test can not be performed with mono-vision contacts). This test is typically covered by your major medical insurance and can be done in office.
Visual Field Testing Procedure:
1. The patient will be instructed to wear their contacts or eye glasses during the test (mono-vision contacts are an exception)
2. The patient will then lean their forehead into the machine and will be instructed to stare at the black dot.
3. The technician will then provide a remote that is to be held in the hand of the patient.
4. Throughout the test, it is critical that the patient's fixation remain on the black dot (do not follow the movement).
5. At 2-7 second intervals, you will see flashes of light or squiggly lines in your periphery or central vision.
6. Each time you see anything other than the black dot, you will be instructed to click the button on the remote.
7. The test is done monocularly (one eye at a time).
8. The machine will automatically cover the eye that should not be used during the test.
9. The test for each eye takes between 4-5 minutes to complete.