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Kaweh Mansouri, Ali Tafreshi, Robert N. Weinreb, Mauro T. Leite, John H. Liu; Effect Of Postural Change On Optic Disc Topographic Measurements Obtained By Ivue Optical Coherence Tomography. Invest. Ophthalmol. Vis. Sci. 2011;52(14):5096.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate changes in optic disc topographic parameters assessed by a portable Spectral Domain optical coherence tomography (SDOCT) (iVue, Optovue Inc., CA) between the sitting and supine body positions.
In this cross-sectional observational study, 40 eyes of 20 subjects (10 healthy young adults [ages 20-27] and 10 older healthy adults [ages 50-66]) were included. All subjects were evaluated in morning hours during a single session. The SDOCT examination protocol consisted of ten scans of each eye in the supine and sitting body positions. Optic disc parameters evaluated in this study were disc area, cup area, rim area and cup volume. The relationship between changes in topographic parameters and change in body position was investigated using generalized estimating equations to adjust for multiple measurements per individual. The agreement between measurements in sitting and supine position was evaluated by plotting the difference between measurements against their mean.
Average age was 22.9 ± 2.6 years in the young and 53.9 ± 4.9 years in the older adult group. In young subjects, optic nerve head volume measurements were 0.51 ± 0.20 µm2 (supine) vs. 0.53 ± 0.19 µm2 (sitting) (p=0.79) and 0.46 ± 0.18 µm2 (supine) vs. 0.45 ± 0.17 µm2 (sitting) (p=0.80) in older healthy adults. Postural change did not have a significant effect on measurements of cup volume in young subjects [0.12 ± 0.14 µm2 (supine) vs. 0.12 ± 0.13 µm2 (sitting) (p=0.98)] or in older adults [0.14 ± 0.10 µm2 vs. 0.14 ± 0.11µm2 (p=0.90)]. There was, however, a tendency for higher posture-dependent changes in eyes with larger cup-volumes (Fig.1; Bland-Altman plot for postural change in cupvolume). In both groups, no statistically significant changes occurred in other parameters such as disc area, cup area, rim area, rim volume, average and maximum cup depth.
In healthy young and adult subjects, posture-dependent changes of optic disc topography were not observed.
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