Spectral-domain optical coherence tomographic assessment of Schlemm's canal in Chinese subjects with primary open-angle glaucoma.
OBJECTIVE
To evaluate in vivo features of Schlemm's canal (SC) in patients with primary open-angle glaucoma (POAG) with spectral-domain optical coherence tomography (SD-OCT) and to investigate the relationship of SC size with intraocular pressure (IOP) and glaucoma severity.


METHODS
Prospective, comparative study.


METHODS
Fifty Chinese patients with newly diagnosed POAG who had not undergone surgery and 50 normal Chinese subjects from a population-based, cross-sectional study in Shanghai.


METHODS
All participants underwent SD-OCT. The diameter and area of SC were examined in the temporal and nasal sections and measured with customized software.


METHODS
Patient demographics, repeatability and reproducibility assessed with the coefficient of variation (CV) and the intraclass correlation coefficient (ICC), SC parameters and their correlation with IOP, and the mean deviation (MD) of the visual field were analyzed.


RESULTS
The percentage of sections in which SC was observable was similar between eyes with POAG and normal eyes, and ranged from 78% to 86%. For intraobserver repeatability, the CV and ICC values were 7.9% and 0.97 for diameter, and 13.8% and 0.83 for area, respectively. For interobserver repeatability, the CV and ICC values were 13.6% and 0.89 for diameter, and 13.4% and 0.80 for area, respectively. Significant differences between the 2 groups were found for the average SC area (11332 ± 2015 μm(2) vs. 13991 ± 1357 μm(2); P<0.001), but not for the SC diameter (40.2 ± 7.1 μm vs. 45.2 ± 4.0 μm; P = 0.195). In addition, the mean IOP values correlated well only with the SC area (ρ = -0.674, P<0.001), not with the SC diameter (ρ = -0.103, P = 248). No significant correlations were found between the MD values and the SC parameters.


CONCLUSIONS
Eyes with POAG have a decreased SC area compared with normal eyes. A correlation between the SC area and the IOP also was observed. However, the degree of glaucoma damage was not consistently associated with the SC area. Spectral-domain OCT could be used for investigating SC changes in patients with glaucoma.
Department of Ophthalmology and Visual Science, Eye, Ear, Nose, and Throat Hospital, School of Shanghai Medicine, Fudan University, Shanghai, China.
Jiaxu
J
Hong
Jianjiang
J
Xu
Anji
A
Wei
Wen
W
Wen
Junyi
J
Chen
Xibao
X
Yu
Xinghuai
X
Sun
D000328:Adult; D000869:Anterior Eye Segment / Q000473:pathology*; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000453:epidemiology / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000295:instrumentation*; D014129:Trabecular Meshwork / Q000473:pathology