Frequency doubling perimetry is a visual field test that presents low spatial frequency gratings flickering at high temporal frequencies, producing an illusion of doubled spatial frequency. It targets specific retinal ganglion cell pathways.
Technique
The patient views flickering striped patterns at various field locations and indicates when they are visible. Thresholds are measured quickly using algorithms designed for screening or full-threshold testing.
- Compact devices are suitable for clinic or community screening
- Testing times are typically shorter than standard automated perimetry
- Stimuli are less affected by refractive blur within certain ranges
- Results are displayed as probability maps and summary indices
Clinical Applications
Frequency doubling perimetry is commonly used for glaucoma screening and early detection of functional loss. Abnormal results often lead to more comprehensive field testing.
- Sensitive to early damage in subsets of magnocellular ganglion cells
- High specificity when appropriate criteria and reliability checks are used
- Useful in settings where rapid assessment is needed
- Interpretation must consider age norms and test reliability indicators
