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Natalie Hutchings, John M. Wild, Michael K. Hussey, John G. Flanagan, Graham E. Trope; The Long-Term Fluctuation of the Visual Field in Stable Glaucoma. Invest. Ophthalmol. Vis. Sci. 2000;41(11):3429-3436.
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© ARVO (1962-2015); The Authors (2016-present)
purpose. To determine, in stable glaucoma, the characteristics of the
between-examination variability of the visual field recorded with the
Humphrey Field Analyser (HFA; Humphrey Systems, Dublin, CA) using the
homogeneous, LF(Ho), and heterogeneous, LF(He), components of the
long-term fluctuation (LF), thereby providing a technique for
separating progressive loss from fluctuation in sensitivity.
methods. The LF components were calculated using a two-factor analysis of
variance (ANOVA) with replications and were determined between each
pair of three successive HFA program 30-2 fields for each patient from
two groups, each containing 30 patients with primary open-angle
glaucoma. The interval between examinations for the first group was 6
to 9 months and for the second group was 3 weeks.
results. The group mean values for LF(Ho) ranged from 1.50 to 2.19 dB and for
LF(He) from 1.70 to 2.05 dB. The average difference between
examinations was within ±0.35 dB for each component, and the 95%
limits of agreement for the two groups, respectively, were ± 2.31
and ± 2.39 dB for the LF(Ho) and ± 2.36 and ± 2.09 dB
for the LF(He). The estimate of the 90% confidence limit for the
LF(Ho) was 3.30 dB and for the LF(He), 3.60 dB. Little relationship was
present between the LF components and the modulus differences in mean
deviation (MD), the corrected pattern SD (CPSD), or the mean MD, mean
short-term fluctuation, and mean CPSD, of the two fields.
conclusions. Estimation of the LF components and of the corresponding confidence
limits yields an expression of the normal between-examination
variability of two consecutive fields that can be used as a reliability
index. A value outside the confidence limits indicates the necessity
for a confirmatory follow-up field.
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