Anterior chamber angle measurement with anterior segment optical coherence tomography: a comparison between slit lamp OCT and Visante OCT.
OBJECTIVE
To compare anterior chamber angle measurements obtained from two anterior segment optical coherence tomography (OCT) instruments and to evaluate their agreements and interobserver reproducibility.


METHODS
Forty-nine eyes from 49 healthy normal subjects were studied. The anterior chamber angle was imaged with the Visante anterior segment OCT (Carl Zeiss Meditec, Dublin, CA) and the slit lamp OCT (SLOCT, Heidelberg Engineering, GmbH, Dossenheim, Germany) on one randomly selected eye in each subject and measured by two independent observers. The angle-opening distance (AOD 500), the trabecular-iris angle (TIA 500), and the trabecular-iris space area (TISA 500) at the nasal and temporal angles were measured. The agreements between SLOCT and Visante OCT measurements and the interobserver reproducibility were evaluated.


RESULTS
The mean nasal/temporal anterior chamber angles measured by Visante OCT and SLOCT were 527 +/- 249/572 +/- 275 microm (AOD), 0.180 +/- 0.091/0.193 +/- 0.102 mm(2) (TISA), and 38.1 +/- 12.3/39.6 +/- 13.2 degrees (TIA); and 534 +/- 234/628 +/- 254 microm (AOD), 0.191 +/- 0.089/0.217 +/- 0.093 mm(2)(TISA), and 37.8 +/- 10.1/40.6 +/- 10.7 degrees (TIA), respectively. No significant difference was found between Visante OCT and SLOCT measurements except the temporal TISA (P = 0.034). The interobserver coefficient of variation ranged between 4.4% and 7.8% for Visante OCT and 4.9% and 7.0% for SLOCT. The spans of 95% limits of agreement of the nasal/temporal angle measurements between Visante OCT and SLOCT were 437/531 mm(2), 0.174/0.186 mm(2), and 25.3/28.0 degrees for AOD, TISA, and TIA, respectively.


CONCLUSIONS
Although Visante OCT and SLOCT demonstrate high interobserver reproducibility for anterior chamber angle measurements, their agreement was poor.
Leung
Christopher Kai-shun
CK
Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Peoples Republic of China. tlims00@hotmail.com
Li
Haitao
H
Weinreb
Robert Neal
RN
Liu
Jing
J
Cheung
Carol Yim Lui
CY
Lai
Ricky Yiu Kwong
RY
Pang
Chi Pui
CP
Lam
Dennis Shun Chiu
DS
D000328:Adult; D000867:Anterior Chamber / Q000033:anatomy & histology*; D000869:Anterior Eye Segment; D006068:Gonioscopy; D006801:Humans; D007498:Iris / Q000033:anatomy & histology*; D015588:Observer Variation; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods*; D014129:Trabecular Meshwork / Q000033:anatomy & histology*