Learning effect and measurement variability in frequency-doubling technology perimetry in chronic open-angle glaucoma

Area of Science:

• Ophthalmology
• Visual Science

Background:

• Glaucoma diagnosis and monitoring rely on visual field testing.
• Frequency-doubling technology (FDT) perimetry is a visual field test.
• Understanding learning effects and test-retest variability is crucial for accurate glaucoma management.

Purpose of the Study:

• To investigate learning effects and measurement variability of FDT perimetry.
• To assess the impact of prior automated static perimetry experience on FDT results.
• To determine optimal testing protocols for reliable FDT perimetry in glaucoma patients.

Main Methods:

• Prospective study of 44 patients with chronic open-angle glaucoma.
• Patients had prior experience with Humphrey automated static perimetry.
• FDT perimetry (N-30 full-threshold program) was administered three times at 1-3 month intervals after an initial screening (C-20-1 program).

Main Results:

• Significant improvement in mean deviation (MD) between the first and second FDT sessions (0.6 dB right eye, 0.8 dB left eye).
• Improved sensitivity in specific test points observed at the second session, but not sustained at the third.
• No significant differences in FDT results between the second and third sessions.
• Test-retest variability (standard deviation of MD) ranged from 3.8 to 4.0 dB.

Conclusions:

• Baseline FDT perimetry measurements in glaucoma patients demonstrate learning effects.
• Repeat testing is necessary to establish stable baseline values.
• Recommend at least two repeat N-30 full-threshold tests after initial C-20-1 screening for reliable perimetric follow-up.