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J.E. DeLeón–Ortega, S.N. Arthur, C.A. Girkin; Effect of Severity of Field Loss on the Precision of Anatomical Measures Using HRT–II, GDx–VCC and StratusOCT in Glaucomatous Eyes . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3672.
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© ARVO (1962-2015); The Authors (2016-present)
Quantitative imaging techniques have been proposed as useful diagnostic tools for detection of progression; however, the effect of severity of field loss on the reproducibility of these techniques is unknown. This study evaluates how visual field mean deviation (MD) is related to 95% confidence interval (CI) from 3 measures of optic nerve head topography using HRT II and of peripapillary nerve fiber layer (RNFL) thickness using GDx–VCC and StratusOCT.
40 eyes from 40 healthy participants and 93 glaucomatous eyes from 93 patients with visual acuity (VA) of 20/40 or better were classified on the basis of standard 24 –2 visual field alone. 28 eyes had early, 22 eyes had moderate, and 43 eyes had severe field loss using Hodapp, Parrish and Anderson criteria. Three consecutive measurements were obtained from each eye using HRT–II, GDx–VCC and StratusOCT, and 95% CIs were then calculated, proportioned to the range of measure at each stage of field loss. Multiple regression evaluated the effect of MD on 95% CI, adjusted for age, logMAR VA, refraction, and lens opacification (LOCS–III).
The following global HRT–II parameters showed a significant association between increased 95% CI with worsening MD: cup volume, height variation contour, and maximum contour elevation and depression (p value < 0.01). For GDx–VCC, 95% CI increased for NFI with worsening MD (p value < 0.001). In contrast, the following StratusOCT parameters showed a significant association between decreased 95% CI with worsening MD: global RNFL (p value < 0.01), and sectorial RNFL at nasal, inferior and temporal quadrants (p value < 0.005).
Increasing severity of field loss affected the 95% CI of repeated anatomical measurements for these imaging techniques with a widening of the 95% CI for some of HRT–II and GDx–VCC parameters despite reduction in the dynamic range indicating that the reproducibility of the techniques are reduced in more severe disease. This effect was not seen with the StratusOCT.
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