Mean deviation fluctuation in eyes with stable Humphrey 24-2 visual fields

Abstract

Aim To describe the expected fluctuation in the mean deviation (MD) scores on a large, long-term series of stable visual field reports for particular grades of defect in order to give clinicians an aid to the correct diagnosis of glaucomatous progression. Method Visual field reports of subjects with five reliable consecutive Humphrey 24-2 visual fields, recorded over a period of at least 3 years, were scored using the Advanced Glaucoma Intervention Study (AGIS) system. The AGIS scores of the first and last visual fields were required to be identical. Results A total of 202 eyes from 202 patients were used in the study, with a total of 1010 visual fields being used in the analysis. Visual fields with no defect (AGIS score 0) had a 99% confidence interval (CI) of 0.3 dB, mild defects 0.4 dB, moderate defects 0.8 dB, severe 1 dB, and 1.3 dB for end-stage defects when considering variation of MD scores. Using a one-way ANOVA incorporating all stages showed very little fluctuation throughout the series (P ¼ 0.96). The correlation between the CI and grade of field defect showed a good positive correlation (r ¼ 0.7, P ¼ 0.0003) indicating an increase in CI as field defects worsen. Conclusion When considering a series of reliable visual fields in a stable eye, one should expect only very little fluctuation in the MD, indicating that an increase in the MD beyond that of the 99% CI described may suggest progression. The reliability indices of the visual field test should be regarded as a primary consideration when assessing visual fields.

The Repeatability of Mean Defect with Size III and Size V Standard Automated Perimetry

“…When using MD to determine a significant change between two tests, a change of 1.4 to 5 dB is needed to be outside the 90% repeatability limits, depending on the size of the stimulus and the amount of visual field damage. This estimate is substantially greater than the results of Tattersall et al 6 For example, with an MD of À10 dB, the width of the 90% repeatability interval is 5.3 dB for size III (requiring a change of 2.6 dB for size III to fall outside the 95% limit). For size V, the width is 4.6 dB with a change of 2.3 dB needed.…”

“…For size V, the width is 4.6 dB with a change of 2.3 dB needed. The corresponding figure from Tattersall et al 6 for the 99% confidence interval for size III is 1.6 dB with a change of 0.8 dB needed to identify positive or negative change. Tattersall and coworkers compacted their data into five bins and calculated the mean and confidence interval for each bin.…”

Visual discrimination training improves Humphrey perimetry in chronic cortically induced blindness

“…Nonetheless, prior work showed changes ≥0.6 dB to be meaningful in glaucoma patients with similarly sized visual loss as our patients. 25 A PMD change of 0.7 dB over placebo was also considered significant in patients with idiopathic intracranial hypertension and mild visual loss (NORDIC Committee 26 ).…”

Ganglion cell and inner plexiform layer thickness determined by spectral domain optical coherence tomography in patients with brain lesions

“…VF is a psychophysical test, the outcome of which depends entirely on the capacity of the examinee to concentrate adequately and perform the necessary tasks. The results of this test are thus frequently subject to intertest variability 23 24. Some patients with poor cognitive function might not perform the VF test sufficiently well to provide accurate results.…”