Abstract
Purpose: :
To determine the ability of the RTVue spectral domain optical coherence tomography (SDOCT) to image the anterior chamber angle (ACA).
Methods: :
Consecutive subjects prospectively underwent ophthalmic evaluation including gonioscopy by an ophthalmologist and anterior chamber imaging with SDOCT (Optovue, Fremont, CA), adapted with a corneal lens adapter (CAM-L module) and anterior segment OCT (ASOCT, Visante, Carl Zeiss Meditec, Dublin, CA), both performed by a technician. The visualization of the scleral spur (SS), Schwalbe’s line (SL) and trabecular meshwork (TM) was assessed by 2 different ophthalmologists, masked to gonioscopy findings, and compared to that with ASOCT. The ability to diagnose a closed angle was compared with that of gonioscopy.
Results: :
The average age of the 81 subjects enrolled was 64.1 (11.4) years; majority were Chinese (91.4%) and female (61.7%). The SS was visible in 26.9% (56/324) quadrants and the SL was detected in 143/324 quadrants (44.1%) in SDOCT images; while in ASOCT images the SS could be visualized in 69.1% of (224/324) quadrants in ASOCT images (p<0.0001); the SL was not visible in ASOCT images. There was no difference in the ability to image the TM (17.3%, p<0.92) using either device. Using the SDOCT, the ACA was gradable for closed angle status in only 41.7% images compared to 71.3% ASOCT images (p<0.0001). ACA was classified as closed in 19.3% quadrants (26/135) with SDOCT images and 31.5% (102/231) ASOCT images compared to 37.7% on gonioscopy. SDOCT and ASOCT showed good agreement with gonioscopy, 0.75 and 0.74, respectively (AC1 statistics) based on analysis of horizontal quadrants.
Conclusions: :
The RTVue SDOCT allowed visualization of the Schwalbe’s line along with the trabecular meshwork and the scleral spur in the ACA. However, the fact that these landmarks were not detected in a large percentage of images means that the technology needs to evolve for integration into routine clinical work.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • anterior chamber