Fatigue effects in automated perimetry.

Area of Science:

• Ophthalmology
• Visual Neuroscience

Background:

• Automated perimetry is crucial for diagnosing and monitoring visual field loss.
• Fatigue is a potential confounding factor in perimetric testing, affecting patient performance.

Purpose of the Study:

• To investigate the impact of fatigue on automated perimetric testing in normal observers and patients with visual field loss.
• To assess the effect of a brief rest midway through testing on fatigue-related performance changes.

Main Methods:

• Evaluated 16 normal observers and 16 patients with visual field loss using a Digilab 750 automated perimeter.
• Measured false positive rate, false negative rate, and detection sensitivity at various eccentricities over a 21-minute test.
• Introduced a 1.5-minute rest midway for half of the participants to assess fatigue reduction.

Main Results:

• Patients exhibited higher false positive and negative rates than normal observers.
• Sensitivity decreased over time, with greater loss at increased stimulus eccentricity.
• Patients showed a more pronounced time-dependent sensitivity loss (~4dB at 20 degrees eccentricity).
• A mid-test break reduced sensitivity loss in the latter half of the examination.

Conclusions:

• Fatigue negatively impacts visual sensitivity during prolonged automated perimetry, particularly in patients with existing visual field deficits.
• A brief interlude during testing can help mitigate fatigue-induced sensitivity decline, enhancing test accuracy.