Skip to Top NavigationSkip to ContentSkip to Footer
Ferris State University BulldogFerris State University Logo

Frequency Doubling Technology (FDT)

Frequency Doubling TechnologyFrequency doubling technology is a method of assessing visual field loss from ganglion cell loss in the retina. Ganglion cells are believed to be the earliest damaged by glaucoma.  The frequency doubling effect occurs when black and white gratings are flickered at a very high rate. This test is a very reliable method to screen for glaucomatous damage.