Frequency doubling technology perimetry using a 24-2 stimulus presentationpattern

Purpose. To assess whether smaller targets and a 24-2 stimulus presentation pattern would improve the ability of frequency doubling technology (FDT) p erimetry to detect and characterize early glaucomatous visual field loss. M ethods. One hundred normal subjects between the ages of 20 and 85 participa ted in this study. In addition, 53 patients who either had early glaucomato us visual field loss (n = 23) or were high-risk glaucoma suspects with norm al conventional visual fields (n = 30) were evaluated with the commercial v ersion of FDT perimetry (full threshold test) with 17 stimuli (four 10 degr ees diameter square targets per quadrant and a central 5 degrees circular t arget) and a custom version of FDT perimetry using 54 stimuli (4 degrees ta rgets with 6 degrees grid spacing) arranged in a 24-2 stimulus presentation pattern. Results. The custom FDT test using a 24-2 stimulus presentation p attern had a similar dynamic range, and demonstrated normal aging character istics and test-retest reliability that were similar to the commercial vers ion of FDT perimetry using 17 larger stimuli. Both FDT tests showed an age- related sensitivity reduction of approximately 0.6 dB per decade, and exhib ited an average test-retest reliability of 1 to 1.5 dB. The custom 24-2 FDT perimetry test had a greater variation of sensitivity with eccentricity th an the commercial version of FDT perimetry that was probably related to the difference in stimulus size. The custom 24-2 FDT perimetry test had a grea ter percentage of abnormal test locations than the commercial FDT test for both early glaucomas and high-risk glaucoma suspects. Conclusions. FDT peri metry can be performed with smaller targets using a presentation pattern th at is similar to conventional automated perimetry. In comparison to the com mercially available 17 target display, the 24-2 stimulus pattern appears to have modestly higher sensitivity for detection of early glaucomatous loss and provides better characterization of the pattern of visual field loss, b ut the test takes approximately twice as long.