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Fatigue effects during a single session of automated static threshold perimetry
C Hudson1, J M Wild, E C O'Neill
1Department of Vision Sciences, Aston University, Birmingham, United Kingdom.
Investigative Ophthalmology & Visual Science
|January 1, 1994
Summary
Visual field testing shows fatigue effects that worsen over time and between eyes, impacting results. Short breaks are insufficient, and current perimetric examination guidelines may need revision.
Area of Science:
- Ophthalmology
- Visual Science
- Clinical Research
Background:
- Perimetry is crucial for diagnosing and monitoring visual field defects.
- Understanding fatigue effects in perimetry is essential for accurate results.
- Ocular hypertension and normal aging can influence visual field test performance.
Purpose of the Study:
- To assess the time course of visual field fatigue during routine perimetry.
- To investigate the impact of rest periods on perimetric fatigue.
- To compare fatigue effects between ocular hypertension and normal subjects.
Main Methods:
- Utilized Octopus 1-2-3 perimeter with Program G1X for 20 normal and 20 ocular hypertensive subjects.
- Calculated global mean defect, loss variance, and hemifield indices.
- Analyzed fatigue effects at different eccentricities and in specific hemifields.
Main Results:
- Visual field indices (mean defect, loss variance) significantly deteriorated over examination stages and between eyes.
- Fatigue effects were more pronounced in peripheral, inferior, and superior/nasal locations.
- Brief rest periods (1-minute intra-eye, 3-minute inter-eye) did not mitigate fatigue.
- No significant performance differences were observed between ocular hypertensive and normal groups.
Conclusions:
- Deterioration of visual field indices suggests current perimetric examination lengths may be suboptimal.
- Confidence limits for abnormality detection should account for fatigue effects.
- Perimetric algorithms may require adjustments, especially for the second eye examination.