Abstract
Purpose: :
To evaluate the agreement and inter-observer reproducibility of anterior chamber angle measurements obtained from two anterior segment optical coherence tomography instruments.
Methods: :
Forty-nine eyes from 49 healthy normal subjects were recruited. The anterior chamber angle was imaged with the Visante anterior segment optical coherence tomography (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 2 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 inter-observer reproducibility were evaluated.
Results: :
The mean nasal / temporal anterior chamber angles measured by Visante OCT and SLOCT were 527±249µm / 572±275µm (AOD), 0.180±0.091mm2 / 0.193±0.102mm2 (TISA), 38.1±12.3º/ 39.6±13.2º (TIA) and 534±234µm / 628±254µm (AOD), 0.191±0.089mm2 / 0.217±0.093mm2 (TISA), 37.8 ±10.1º /40.6±10.7º (TIA), respectively. No significant difference was found between Visante OCT and SLOCT measurements except the temporal TISA (p=0.034). The inter-observer coefficient of variation ranged between 4.4-7.8% for Visante OCT and 4.9-7.0% for SLOCT. The spans of 95% limits of agreement of the nasal / temporal angle measurements between Visante OCT and SLOCT were 437µm / 531µm, 0.174mm2 / 0.186mm2, and 25.3º / 28.0º for AOD, TISA and TIA, respectively.
Conclusions: :
Although Visante OCT and SLOCT demonstrate high inter-observer reproducibility for anterior chamber angle measurements, their agreement is poor.
Keywords: anterior chamber • imaging/image analysis: clinical