Fluctuations in Threshold and Effect of Fatigue in Automated Static Perimetry (with the Octopus 201)

The influence of prior perimetric experience on the magnitude of both differential sensitivity and the short and long term fluctuations remains unclear, and confounds accurate interpretation of visual field data obtained by computer-assisted perimetry. The purpose of the experiment was to identify and quantify any influence of training on the automated perimetric response. The full field of the right eye of 10 clinically normal, naive subjects was examined on 8 occasions with Octopus Program 21 (target size 3) on days 1-5 inclusive, 15, 16 and 44. Sensitivity increased with serial examination in 8 subjects. By dividing the field into zones, it was demonstrated that the learning effect was greatest in the superior field and for eccentricities beyond 30 degrees.

supporting

confidence: 87%

Serial examination of the normal visual field using Octopus automated projection perimetry Evidence for a learning effect

Wood

Wild

Hussey

et al. 1987

“…a fatigue effect, also influences the outcome of automated perimetry. Rabineau et al (1985) found no appreciable difference in sensitivity in 8 normal subjects who underwent four successive central field examinations over the course of 1 h with the Octopus perimeter (Program 31). Fatigue effects which increase with the duration of examination and which are greatest in, or adjacent to, relative scotomata, however, have been reported in glaucoma (He41 1977;Heijl & Drance 1983;Johnson et al 1988;Langerhorst 1988) and a fatigue effect in cases of optic neuropathies has also been noted (Wildberger & Robert 1988).…”

mentioning

confidence: 94%

Long‐term follow‐up of baseline learning and fatigue effects in the automated perimetry of glaucoma and ocular hypertensive patients

Wild

Searle

Dengler-Harles

et al. 1991

The detection of change in the visual field is confounded by factors associated with the patient response. Sixteen patients who had previously undergone a training regime in automated perimetry over a short time period were followed up to evaluate the longer term learning and fatigue effects. The patients, all attending a glaucoma clinic, were originally naive to automated perimetry. The training period had comprised examination of the right followed by that of the left eye with the Humphrey Field Analyser 630 on each of 3 successive days and again after an interval of 12 days. The follow-up study comprised two examinations on 2 successive days after a follow-up period of between 5 and 15 months (mean 8.7 months). The learning effects present over the initial training period were not observed at the follow-up whilst the fatigue effects in the fellow eye were still apparent.

“…Several other authors have assumed a learning effect in testing normal individuals using automated perimetry ( F l a m e r et Wilensky & Joondeph 1984). Conversely, other reports have failed to note a learning effect in normal individuals after repeated examinations (Aulhorn & Harms 1972;Rabineay et al 1985).…”

Section: Discussionmentioning

confidence: 99%

Factors associated with a learning effect in glaucoma patients using automated perimetry

Kulze

Stewart

Sutherland

1990

We studied 45 primary open-angle glaucoma patients consecutively examined with the program 30-2 on the Humphrey Field Analyzer to determine factors associated with a learning effect between the first two visual field exams. The average mean defect significantly decreased 1.7 dB between exams (P less than 0.05). No difference was noted in learning based on: the time interval between tests, the area of the field tested, age, sex, race, previous perimetric experience or parameters on the initial field exam (i.e. prevalence of false positive and negative errors, central reference level and eye tested (P greater than 0.05). However, learning positively correlated to defect depth and negatively correlated to fixation losses on the initial exam in patients retested within seven months (P less than 0.05). This study suggests predicting which patients require a second baseline field exam to exclude a learning effect is difficult, except in those with glaucomatous field loss or few fixation losses and another field is planned within a half year.