Repeatability and reproducibility of anterior chamber angle measurement with anterior segment optical coherence tomography.
OBJECTIVE
To evaluate the repeatability and reproducibility of anterior chamber angle measurement obtained by anterior segment optical coherence tomography.


METHODS
Twenty-five normal subjects were invited for anterior chamber angle imaging with an anterior segment optical coherence tomography (OCT) on one randomly selected eye in three separate visits within a week. Each eye was imaged three times under room light (light intensity = 368 lux) and three times in the dark during the first visit. In the subsequent visits, each eye was imaged once in the light and once in the dark. The angle opening distance (AOD 500) and the trabecular-iris angle (TIA 500) were measured by a single observer. Only the nasal angle was analysed. Intrasession and intersession within-subject standard deviation (Sw), precision (1.96xSw), coefficient of variation (CVw) (100xSw/overall mean), and intraclass correlation coefficient (ICC) were calculated to evaluate repeatability and reproducibility.


RESULTS
For intrasession repeatability, the Sw, precision, CVw and ICC of AOD/TIA were 45 microm/2.4 degrees , 88 microm/4.7 degrees , 5.8%/4.8% and 0.97/0.95 in the light; and 45 microm/2.1 degrees , 88 microm/4.2 degrees , 7.0%/5.0% and 0.98/0.97 in the dark. For intersession reproducibility, the Sw, precision, CVw and ICC of AOD/TIA were 79 microm/3.5 degrees , 155 microm/6.8 degrees , 10.0%/7.0%, 0.91/0.89 in the light; and 64 microm/3.4 degrees , 124 microm/6.6 degrees , 9.9%/7.8% and 0.95/0.92 in the dark.


CONCLUSIONS
The anterior segment OCT demonstrated reliable anterior chamber angle measurement in different lighting conditions with good repeatability and reproducibility.
Li
Haitao
H
Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, 147K Argyle Street, Kowloon, Hong Kong
Leung
Christopher Kai Shun
CK
Cheung
Carol Yim Lui
CY
Wong
Lee
L
Pang
Chi Pui
CP
Weinreb
Robert Neal
RN
Lam
Dennis Shun Chiu
DS
D000328:Adult; D000867:Anterior Chamber / Q000033:anatomy & histology*; D006801:Humans; D007498:Iris / Q000033:anatomy & histology; D008029:Lighting; D010775:Photic Stimulation / Q000379:methods; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods*; D014129:Trabecular Meshwork / Q000033:anatomy & histology