Purpose:
To describe, evaluate and classify in vivo the areas of junction between Schlemm’s canal (SC) and the collector channels (CC) in normal adult human eyes using a novel technique of serial high definition anterior segment Fourier-domain OCT imaging (ASFDOCT).
Methods:
20 normal subjects (mean age: 25±4.0 years) were imaged using ASFDOCT scans over the right temporal limbus. The area was first inspected for CCs. When a clearly visible SC-CC junction was identified, a standardized protocol of serial radial and tangential scans was performed. The highest quality image of each set capturing the ostium of the same CC in both scan orientations was selected for quantitative assessment. The serial scans were used to create composite images which were qualitatively evaluated.
Results:
In the radial scans, we evaluated SC cross sectional area (9,248±2,500 µm²), maximum width (28±10 µm) and length (365±46 µm) as well as CC maximum lumen diameter (12±4 µm). The ostium diameter (18±8 µm) and SC maximum (28±9 µm) and minimum width (12±6 µm) in a 500 µm long section around the junction were evaluated in the tangential scans. Based on their morphometry, CC were classified into small or large; based on their course, they were divided in anterior and posterior CC.
Conclusions:
The anatomy of the SC-CC junctions can be objectively measured with real-time, high resolution ASFDOCT and is enhanced by the use of serial radial and tangential imaging. We propose a classification of the CC based on their in vivo anatomy.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • outflow: trabecular meshwork • aqueous