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Abstract #19602 Published in IGR 9-3
Dynamic analysis of dark light changes of the anterior chamber angle with anterior segment OCT
Leung CK; Cheung CY; Li H; Dorairaj S; Yiu CK; Wong AL; Liebmann J; Ritch R; Weinreb R; Lam DSInvestigative Ophthalmology and Visual Science 2007; 48: 4116-4122
See also comment(s) by Tin Aung •
PURPOSE: To describe the use of anterior segment optical coherence tomography (OCT) in studying the dynamic dark-light changes of the anterior chamber angle. METHODS: Thirty-seven normal subjects with open angles on dark-room gonioscopy and 18 subjects with narrow angles were analyzed. The dynamic dark-light changes of the anterior-chamber angle were captured with real-time video recording. The angle opening distance (AOD500) and trabecular iris space area (TISA500) of the nasal angle and the pupil diameter in each of the representative serial images were measured. Linear regression analysis was performed to investigate the association between AOD500/TISA500 and pupil diameter. Demographic and biometry measurements associated with the AOD difference (AOD500((light)) - AOD500((dark))) and TISA difference (TISA500((light)) - TISA500((dark))) were analyzed with univariate and multivariate regression models. RESULTS: The AOD500/TISA500 measured in the light in the open-angle and the narrow-angle groups were 694 ± 330 mum/0.24 ± 0.10 2 and 265 ± 78 mum/0.10 ± 0.03 2, respectively. These values were significantly greater than the AOD500/TISA500 measured in the dark (492 ± 265 mum/0.16 ± 0.08 2 and 119 ± 82 mum/0.05 ± 0.04 2, respectively, all with P < 0.001). The ranges of the AOD/TISA difference were 13 to 817mum/0.011 to 0.154 2, with an average of 180 mum/0.073 2. Multivariate regression analysis identified a positive correlation between anterior chamber depth and the AOD/TISA difference. Fifty eyes showed significant correlations between AOD/TISA and pupil diameter, whereas one eye showed no association. Four eyes in the narrow angle group developed appositional angle closure in the dark. CONCLUSIONS: The dynamic dark-light changes of the anterior chamber angle can be imaged and analyzed with anterior segment OCT. Although the angle width generally decreased linearly with increasing pupil diameter, the differences of the angle width measured in the dark and in the light varied substantially among individuals.
Dr. C.K. Leung, Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Peoples Republic of China
Classification:
6.9.2.1 Anterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)