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D.C. Guaqueta, M. Sehi, W.J. Feuer, D.S. Greenfield; A Comparison of Structural Measurements Using Two StratusTM Optical Coherence Tomography (OCT) Instruments . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3640.
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© ARVO (1962-2015); The Authors (2016-present)
To compare retinal nerve fiber layer (RNFL) thickness measurements generated using two different StratusTM optical coherence tomography (OCT) instruments.
One randomly selected eye among healthy volunteers underwent OCT imaging by two experienced operators using two OCT instruments. The order of the machines and operators were randomized. Outcome measures included average, superior, and inferior RNFL thickness. For each OCT measurement a MINQUE variance component analysis of the proportion of variance due to subject, operator, and machine was calculated.
Ten eyes of 10 healthy volunteers were enrolled (age 41±8.1 years). Average and inferior RNFL thickness for machine 1 (97.6±7.4, 123.3±19.3) was significantly different (p=0.001, paired t–test) compared with average and inferior RNFL thickness from machine 2 (103.1±9.5, 129.8±16.8). Signal strength was significantly (p=0.001) associated with average RNFL thickness. Average, inferior and superior measurement variance attributable to operator was 2.9%, 7.8%, and 10.6%, respectively. Variance attributable to machine was 6.9%, 4.7%, and 15.5%, respectively.
Differences in RNFL measurements exist between OCT instruments but the between–machine variance is comparable to between–operator variability.
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