Abstract
Purpose: :
To evaluate anterior chamber angle structures by using two- and three-dimensional anterior segment optical coherence tomography (2D- and 3D-OCT).
Methods: :
A total of 68 eyes from 14 normal volunteers and 20 narrow angle patients were evaluated using 2D-OCT (Visante; Carl Zeiss Meditec, Dublin, California) and 3D-OCT (CASIA; Tomey, Aichi,Japan). The mean age was 52.6 ± 24.2 years old (mean ± standard deviation). In 2D-OCT measurements, normal and enhanced images were used. The enhanced images are created from four registered OCT images. The measurement parameters include visibility of the scleral spur (SS) and trabecular meshwork (TM), and AOD 500 (angle opening distance). The visibility of SS and TM was scored from 1 (invisible) to 4 (clearly visible).
Results: :
The visibility scores for TM were 2.9 ± 0.9, 3.2 ± 0.9, 3.3 ± 0.9 in normal 2D-OCT, enhance 2D-OCT, and 3D-OCT, respectively. The score was significantly lower in normal 2D-OCT than in enhance 2D-OCT (P = 0.006, analysis of variance with Bonferroni comparison) and in 3D-OCT (P = 0.001). The visibility scores for SS were 2.2 ± 0.9, 2.6 ± 1.1, 3.1 ± 1.0 in normal 2D-OCT, enhance 2D-OCT, and 3D-OCT, respectively. The score was significantly greater in 3D-OCT than in normal and enhance 2D-OCT (P < 0.0001). There was also significant difference between normal and enhance 2D-OCT (P = 0.002). There was no significant difference in AOD 500 among the three methods (P = 0.835).
Conclusions: :
The 3D-OCT allows significantly better visibility of anterior chamber angle structures than 2D-OCT. Detail analysis of trabecular meshwork and scleral spur is possible with anterior segment 3D-OCT.
Keywords: imaging/image analysis: clinical • anterior segment • anterior chamber