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Chris A. Johnson, Genichiro Takahashi, Shaban Demirel; The ability of frequency doubling technology (FDT) perimetry to predict the onset of glaucomatous visual field loss for standard automated perimetry (SAP). Journal of Vision 2002;2(10):100. doi: https://doi.org/10.1167/2.10.100.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate the ability of Frequency Doubling Technology (FDT) to predict the development of glaucomatous Standard Automated Perimetry (SAP) deficits in glaucoma suspects (converters).
Methods: FDT perimetry was conducted using a custom display system (Quadravision) that consisted of four high resolution (1280 × 1600 pixels) 21 inch monochrome monitors combined with front surface mirrors to cover the central 30 degrees radius of the visual field. A 24-2 stimulus presentation pattern (6 degree grid bracketing the horizontal and vertical meridians), consisting of 54 locations throughout the central 24 degrees radius, was employed for FDT testing. The targets were 4 degree diameter squares, which displayed 0.5 cycle/degree sinusoidal gratings undergoing 18 Hz counterphase flicker. Background luminance was 50 cd/m2. Thresholds were obtained by means of a Modified Binary Staircase (MOBS) procedure. SAP visual fields were obtained with the Humphrey Field Analyzer II (Model 750), using a 24-2 stimulus display, the standard background luminance (10 cd/m2), the standard stimulus size (III) and a Full Threshold procedure. 119 eyes of 89 glaucoma suspects (with normal SAP visual fields at baseline) were evaluated with FDT and SAP annually over a four year time period.
Results: Results of a multivariate analysis (CART) revealed that the Pattern Standard Deviation (PSD) index for FDT at baseline was able to predict the development of SAP deficits four years later. 13 out of 19 SAP converters and 84 out of 100 SAP non-converters were correctly identified using the baseline FDT PSD alone (area under ROC = 0.74). The efficacy of additional FDT parameters will also be presented.
Conclusions: FDT perimetry appears to detect glaucomatous visual field losses prior to SAP in most instances. In addition, FDT visual field abnormalities seem to be predictive of the future development of glaucomatous visual field loss for SAP.
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