Schlemm's Canal Expands After Trabeculectomy in Patients With Primary Angle–Closure Glaucoma

Hong, Jiaxu; Yang, Yujing; Wei, Anji; Deng, Sophie X.; Kong, Xiangmei; Chen, Junyi; Girard, M; Mari, Jean-Martial; Xu, Jianjiang; Sun, Xinghuai

doi:10.1167/iovs.14-14712

Cited by 33 publications

(27 citation statements)

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“…11,19,[30][31][32] The SC detectable rates of these studies vary significantly. Our results show that the detectable rate of SC in the superior, inferior, nasal, and temporal quadrants varied.…”

Section: Discussionmentioning

confidence: 99%

“…The SC area was drawn freehand and depicted the area surrounded by the outline of SC, as shown in Figure 1. 11 The mean of the superior, nasal, inferior, and temporal SC was included in the analysis.…”

Section: Sc Measurementsmentioning

confidence: 99%

“…Similarly, expansion of SC was also detected after trabeculectomy and proved to be associated with the extent of IOP reduction. 11 Yet, we still know little about the physiology of SC in normal people. As there is IOP fluctuation throughout the whole day, [12][13][14] it is not known if there will be ''morphological fluctuation'' of the SC.…”

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confidence: 99%

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Diurnal Variations in the Morphology of Schlemm's Canal and Intraocular Pressure in Healthy Chinese: An SS-OCT Study

Gao

Aung

et al. 2017

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To characterize the diurnal variations in the dimensions of the Schlemm's canal (SC) and its association with intraocular pressure (IOP) using swept-source optical coherence tomography (SS-OCT).METHODS. The temporal, nasal, inferior, and superior limbus of 102 eyes of 51 healthy subjects were imaged in vivo by SS-COT at 5 time points of 8 AM, 11 AM, 2 PM, 5 PM, and 8 PM. IOP was measured at the same time by Goldmann applanation tonometry (GAT). The diameter and the cross-sectional area of the SC were measured in ImageJ. The associations between changes in the SC parameters, IOP, and other biometric parameters were determined using a general estimating equations model. The temporal and inferior limbus of 94 eyes of 47 healthy subjects were also imaged before and during the Valsalva maneuver (VM) at 8 PM. RESULTS.Mean IOPs at different time points were 13.37, 12.89, 11.9, 12.02, and 12.36 mm Hg. Of all four quadrants, the detectable rate of SC was highest in the superior quadrant (85.3%) and lowest in the inferior quadrant (75.5%). We found that changes in the SC area and diameter were negatively associated with IOP changes only in the inferior quadrant (P ¼ 0.0046 and P ¼ 0.0332, respectively), after adjusting for age, sex, eye, spherical equivalent, and axial length. The mean SC area and diameter during the VM were significantly higher than prior to the VM (P < 0.001).CONCLUSIONS. The changes in the SC parameters were negatively associated with IOP changes only in the inferior quadrant. The VM could expand the SC in healthy subjects. Imaging of the SC may be a useful method to discover the reason why IOP fluctuates, and how SC changes morphologically during the daytime in the future.Keywords: Schlemm's canal, intraocular pressure, Valsalva maneuver T he rate of ocular aqueous humor (AH) drainage can affect intraocular pressure (IOP).1 In normal people, the aqueous humor is mainly drained through trabecular meshwork into the Schlemm's canal (SC), and then it flows into collector canals and episcleral veins. Aging, inflammation, and other immune factors could change the structural component in the outflow pathway of the AH, leading to imbalance in AH dynamics. [2][3][4] Blockage in any of the structures above will lead to the obstruction of AH drainage, causing ocular hypertension. 5Elevated IOP is an important risk factor for glaucoma and optic nerve damage. 6 Before the 21st century, the observation of SC in vivo was limited by imaging techniques. With the invention of highresolution optical coherence tomography (OCT), SC imaging in vivo became possible. Previous studies using OCT demonstrated that the SC area in patients with primary open angle glaucoma (POAG) and pseudoexfoliation glaucoma was decreased compared to normal people. [7][8][9] In addition, the morphology of SC can be affected by the application of prostaglandins and surgery. A study by Chen et al. 10 showed that the SC area expanded following the use of travoprost in healthy subjects. Similarly, expansion of SC was also detected after trab...

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Section: Discussionmentioning

confidence: 99%

Section: Sc Measurementsmentioning

confidence: 99%

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Diurnal Variations in the Morphology of Schlemm's Canal and Intraocular Pressure in Healthy Chinese: An SS-OCT Study

Gao

Aung

et al. 2017

Invest. Ophthalmol. Vis. Sci.

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“…Using SD-OCT to evaluate the in vivo changes in Schlemm's canal (SC) in patients with primary angle-closure glaucoma after trabeculectomy, Hong and associates 24 observed a significant increase in the diameter and area of SC at the follow-up examination compared with the baseline value (SC diameter ± standard deviation [SD]: 34.2 ± 6.2 μm and 28.4 ± 6.1 μm, respectively; SC area: 8117 ± 1942 μm(2) and 5200 ± 996 μm(2), respectively; all P < 0.001). Change in IOP was the only variable related to changes in SC after multivariate analysis (SC diameter, P = 0.002; SC area, P < 0.001).…”

Section: Introductionmentioning

confidence: 99%

“…Change in IOP was the only variable related to changes in SC after multivariate analysis (SC diameter, P = 0.002; SC area, P < 0.001). 24 …”

Section: Introductionmentioning

confidence: 99%

One Year of Glaucoma Research in Review—2013 to 2014

Tassel

Radcliffe

Demetriades³

2015

Asia-Pacific Journal of Ophthalmology

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Purpose The purpose of this study was to provide the practicing clinical ophthalmologist with an update of relevant glaucoma literature published from 2013 to 2014. Design Literature review. Methods The authors conducted a 1-year (October 1, 2013, to September 30, 2014) English-language glaucoma literature search on PubMed of articles containing “glaucoma” or “glaucomatous” with title/abstract as a filter. Medical Subject Headings (MeSH) filtered searching was not performed because of the newness of the reviewed material. Results Literature review yielded 2,314 articles, after which we excluded reviews and letters to the editor. We highlighted articles featuring new or updated approaches to the pathophysiology, diagnosis, or treatment of glaucoma and gave preference to human research. Conclusions This review features literature that is of interest to ophthalmologists in practice and also highlights studies that may provide insight to future developments applicable to clinical ophthalmology.

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Long-term outcomes of viscocanalostomy and phaco-viscocanalostomy in patients with narrow angle glaucoma

Berman

Somerville

Choudhary

2021

Graefes Arch Clin Exp Ophthalmol

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Schlemm's Canal Expands After Trabeculectomy in Patients With Primary Angle–Closure Glaucoma

Abstract: Expansion of SC was observed after trabeculectomy in PACG patients. The degree of SC expansion was related to the extent of the IOP decrease.

Cited by 33 publications

References 14 publications

Diurnal Variations in the Morphology of Schlemm's Canal and Intraocular Pressure in Healthy Chinese: An SS-OCT Study

Diurnal Variations in the Morphology of Schlemm's Canal and Intraocular Pressure in Healthy Chinese: An SS-OCT Study

One Year of Glaucoma Research in Review—2013 to 2014

Long-term outcomes of viscocanalostomy and phaco-viscocanalostomy in patients with narrow angle glaucoma

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