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A. Narayanaswamy, L. M. Sakata, M. He, R. Lavanya, M. Baskaran, D. S. Friedman, P. J. Foster, T. Aung; Diagnostic Performance of Anterior Chamber Angle Measurements in Detecting Eyes at Risk for Angle Closure - An Anterior Segment OCT Study. Invest. Ophthalmol. Vis. Sci. 2009;50(13):3352.
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© ARVO (1962-2015); The Authors (2016-present)
To assess the diagnostic ability of anterior chamber angle measurements performed on anterior segment optical coherence tomography [(ASOCT), Visante, Carl Zeiss Meditec] images in identifying eyes at risk for angle closure.
This was a cross-sectional study of 2047 phakic subjects aged ≥ 50 years without ophthalmic symptoms who were recruited from a community polyclinic in Singapore. All subjects were imaged in the dark by a single operator. Gonioscopy was performed by an ophthalmologist masked to the ASOCT findings. Angle closure was defined as inability to visualize at least 180º of posterior pigmented trabecular meshwork on non-indentation gonioscopy in the primary position. Horizontal scans of right eyes of these subjects were analyzed for following quantitative parameters using the Zhongshan Angle Assessment Program (ZAAP): Angle opening distance (AOD) 250, 500, and 750 um from the sclera spur, trabecular-iris space area (TISA) 500,750 and angle recess area (ARA). The area under the receiver operating characteristic curve (AUC) was generated to assess the performance of these measurements in detecting eyes with angle closure.
Of 2047 people examined, 522 (25.5%) were excluded from analysis due to poor scleral spur localization and 60 (2.9%) were excluded due to image artifacts .Of the remaining 1465 participants, 315 (21.5%) had angle closure on gonioscopy. The mean age was 62.7 ± 7.7 (Range: 50.0 -93.3) years, 54.1% were females, 90 % were of Chinese origin. AUC was highest for AOD750 both in the nasal [0.90(95% confidence interval [CI] 0.89-0.92)] and temporal [0.91(95% CI, 0.90-0.93)] quadrants. AUC for TISA750 in the nasal quadrant and temporal quadrant was 0.87 (95% CI, 0.85-0.89) and 0.88 (95% CI, 0.86-0.89) respectively. The AUC generated for ARA in the nasal quadrant and temporal quadrant was 0.83 (95% CI, 0.81-0.85) and 0.84 (95% CI, 0.82-0.86) respectively.
Using ASOCT, AOD750 was the most useful angle parameter to identify subjects with gonioscopic angle closure with an AUC of 0.90. Poor definition of the scleral spur may preclude the quantitative analysis in approximately 25% of the ASOCT images.
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