Characteristics and variations of in vivo Schlemm's canal and collector channel microstructures in enhanced-depth imaging optical coherence tomography

• Published in: British journal of ophthalmology Vol. 101; no. 6; pp. 808 - 813
• Main Authors: Li, Pengcheng, Butt, Anum, Chien, Jason L, Ghassibi, Mark P, Furlanetto, Rafael L, Netto, Camila F, Liu, Yiyi, Kirkland, Wendy, Liebmann, Jeffrey M, Ritch, Robert, Park, Sung Chul
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01.06.2017
• Subjects: Adult; Aqueous Humor - metabolism; Cross-Sectional Studies; Female; Healthy Volunteers; Humans; Imaging, Three-Dimensional - methods; Intraocular Pressure - physiology; Limbus Corneae - cytology; Limbus Corneae - metabolism; Male; Prospective Studies; Reproducibility of Results; Tomography, Optical Coherence - methods; Trabecular Meshwork - cytology; Trabecular Meshwork - metabolism; Young Adult; Glaucoma; Anatomy; Aqueous humour; Imaging
• ISSN: 0007-1161; 1468-2079
• DOI: 10.1136/bjophthalmol-2016-309295

Background/aimsTo characterise in vivo Schlemm's canal (SC) and collector channels (CC) microstructures using enhanced-depth imaging (EDI) optical coherence tomography (OCT).MethodsSerial horizontal EDI OCT B-scans (81 scans, 15×5° rectangle) were prospectively obtained in the nasal and temporal limbus. SC cross-sectional area (CSA) was measured by delineating its lumen in each B-scan. CCs connected to SC were counted. SC CSA and the number of CCs were compared between the nasal and temporal areas.ResultsEleven eyes (11 normal subjects) were included (mean age, 28±5 years). SC and CCs were clearly demarcated in EDI OCT B-scans with excellent repeatability and reproducibility (intraclass correlation coefficients, 0.830–0.886 and 0.793, respectively; all p<0.001). SC CSA varied considerably among subjects, ranging from 1664 to 6007 µm2 (average, 3514±1235 µm2), and among different regions of the same eye with coefficient of variation in each eye ranging from 23% to 46% (average, 32±7%). The number of CCs in the analysed area also varied considerably among subjects, ranging from 5 to 11 (average, 8.73±1.85). The mean SC CSA (3839±1402 µm2 vs 3189±1209 µm2; p=0.033) and number of CCs (5.5±1.4 vs 3.3±1.1; p=0.001) were significantly greater nasally than temporally. The mean SC CSA was significantly correlated with the number of CCs (r=0.635, p=0.036).ConclusionsHigh-quality images of the aqueous outflow pathway can be obtained with a clinical device, avoiding postacquisition processing. In vivo SC and CC microstructures vary considerably among individuals and regions. SC tends to be larger in regions with more CCs.