Author(s): Le PV, Zhang X, Francis BA, Varma R, Greenfield DS,
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Abstract PURPOSE: To report the baseline characteristics of the participants in the Advanced Imaging for Glaucoma Study. To compare the participating sites for variations among subjects and the performance of imaging instruments. DESIGN: Multicenter longitudinal observational cohort study. METHODS: A total of 788 participants (1329 eyes) were enrolled from 3 academic referral centers. There were 145 participants (289 eyes) in the normal group, 394 participants (663 eyes) in the glaucoma suspect/preperimetric glaucoma group, and 249 participants (377 eyes) in the perimetric glaucoma group. Participants underwent a full clinical examination, standard automated perimetry, and imaging with time-domain and Fourier-domain optical coherence tomography (OCT), scanning laser polarimetry, and confocal scanning laser ophthalmoscopy. The baseline average, population standard deviation, and repeatability of imaging-derived anatomic variables were reported for each technology and center. RESULTS: Compared to the normal participants, glaucoma suspect/preperimetric glaucoma and perimetric glaucoma groups had significantly reduced anatomic measurements. Repeatability of nerve fiber layer thickness was best for Fourier-domain OCT (overall coefficient of variation <2\%), followed by time-domain OCT (coefficient of variation 2\%-2.9\%), scanning laser polarimetry (coefficient of variation 2.6\%-4.5\%), and confocal scanning laser ophthalmoscopy rim area (coefficient of variation 4.2\%-7.6\%). A mixed-effects model showed that the differences between sites was less than 25 percent of the variation within groups and less than the differences between the normal and glaucoma suspect/preperimetric glaucoma group. CONCLUSIONS: Site-to-site variation was smaller than both the variation within groups and the changes attributable to glaucoma. Therefore pooling of participants between sites is appropriate. Copyright © 2015 Elsevier Inc. All rights reserved.
This article was published in Am J Ophthalmol
and referenced in Journal of Clinical & Experimental Ophthalmology