Abstract
Purpose: :
To evaluate the usefulness of Fourier-domain (FD) anterior segment optical coherence tomography (AS-OCT) in scleral spur detection and anterior chamber angle measurements in comparison with time-domain (TD) AS-OCT in eyes with narrow angle.
Methods: :
All participants underwent gonioscopy, FD-OCT (SS-1000, Tomey, Nagoya, Japan), and TD-OCT (Visante; Carl Zeiss Meditec, Dublin, California). Scleral spur location was assessed in AS-OCT images by masked examiner and was defined as the point where there was an inward protrusion of the sclera with a change in curvature of its inner surface. Angle opening distance (AOD) and the trabecular-iris space area (TISA) were measured semi-automatically from OCT images.
Results: :
Forty eyes of 20 patients (3 men, 17 women) with narrow angle were enrolled. Of the 40 eyes, 13 eyes were classified as primary angle closure suspect, 18 eyes were classified as primary angle closure, and 9 eyes were classified as primary angle closure glaucoma. The scleral spur was detectable with TD-OCT in 16 images (20%) in nasal/temporal images while the scleral spur was detectable with FD-OCT in 49 images (62%). The difference was statistically significant (p<0.001, Fisher exact test). The average AOD and TISA measured by TD-OCT and FD-OCT in 15 images in which scleral spur was detectable with both OCTs, the mean anterior chamber angles measured by TD-OCT and FD-OCT were 0.248/0.205mm (AOD500, p=0.18, paired t-test) and 0.088/0.041 mm2 (TISA500, p<0.05, paired t-test), respectively.
Conclusions: :
FD-OCT was superior to TD-OCT in detecting scleral spur in patients with narrow angle. Anterior chamber angle measurement values were generally lower in FD-OCT analysis.
Keywords: imaging/image analysis: clinical • anterior chamber • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)