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A. Shah, D. Sinapis, A. Sinapis, C. Bunce, D. Garway-Heath; Inter- and Intra- Observer Agreement of Anterior Segment-OCT Iris Profile Measurements in Pigment Dispersion Syndrome. Invest. Ophthalmol. Vis. Sci. 2010;51(13):5539. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Accurate assessment of iris profile in pigment dispersion syndrome (PDS) is important in studying the pathogenesis of this condition and in evaluating the role of Nd:YAG laser iridotomy in eliminating backwards bowing of the iris. The aim of this study was to determine between- and within-observer agreement of anterior segment optical coherence tomography (AS-OCT) iris profile measurements in patients with PDS.
50 consecutive patients with PDS underwent AS-OCT imaging of horizontal quadrants. The eye with the least flat iris profile was selected from each eye pair. For eye pairs with equal iris curvatures, one eye was selected at random. Iris curvature was quantified using ASOCT software to measure the maximum deflection of the posterior pigmented iris epithelium from a straight line joining the inner and outer iris extremity. This was performed independently by 2 observers for both temporal and nasal quadrants. Observer one repeated the measurements on the same set of images 1 week later. Nasal and temporal quadrants were analysed separately. Agreement between and within observers was assessed using Bland-Altman plots. In addition, iris profiles were classified as planar, convex or concave and agreement assessed using a weighted Kappa statistic (Κ).
One image was excluded as it was deemed ungradeable by one observer. The range of maximum deflections was -0.45 mm (concave) to 0.32 mm (convex). 95% confidence intervals for limits of agreement of maximum deflection were -0.07 to 0.05 mm between observers and -0.06 to 0.07 mm within observer. For profile classification, agreement between observers was Κ=0.96 (temporal quadrant) and 0.89 (nasal quadrant).Within an observer, Κ=0.93 (temporal quadrant) and 0.94 (nasal quadrant).
Using the protocol devised for this study, ‘very good’ within- and between-observer agreement was demonstrated in quantifying iris profile. The repeatability of these measurements is presently under investigation.
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