The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform
Sung-chul Park - One of the best experts on this subject based on the ideXlab platform.
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microarchitecture of Schlemm Canal before and after selective laser trabeculoplasty in enhanced depth imaging optical coherence tomography
Journal of Glaucoma, 2017Co-Authors: Alon Skaat, Jason L Chien, Mark P Ghassibi, Jeffrey M. Liebmann, Robert Ritch, Michael S Rosman, Sung-chul ParkAbstract:PURPOSE To characterize the in vivo effect of selective laser trabeculoplasty (SLT) on the Schlemm Canal (SC) in eyes with primary open-angle glaucoma (POAG). MATERIALS AND METHODS Eighty-one serial horizontal enhanced depth imaging optical coherence tomograph B-scans (interval between B-scans, ∼35 μm) of the nasal corneoscleral limbus were obtained before and 4 weeks after SLT. Fifty B-scans in the overlapping regions before and after SLT were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The SC cross-sectional area (CSA) was measured in each selected B-scan and averaged to generate the mean SC CSA of the eye. SC volume in the overlapping region was calculated using commercially available 3-dimensional reconstruction software. The mean SC CSA and SC volume were compared between pre-SLT and post-SLT B-scans. Correlation analysis was performed between SC CSA changes and intraocular pressure (IOP) changes. RESULTS Thirteen POAG eyes (13 patients) were included for analysis (mean age, 68.2±9.2 y). After SLT, the mean IOP was reduced from 19.8±7.6 to 14.4±3.8 mm Hg (P=0.003); the mean SC CSA increased by 8%, from 2478±550 to 2682±598 μm (P=0.029); and the mean SC volume increased from 4,304,592±954,777 to 4,658,250±1,039,956 μm (P=0.029). Increase in SC CSA had a significant positive correlation with IOP reduction after SLT (P=0.023, R=0.622). CONCLUSIONS SLT expands SC in POAG patients and even more so with greater IOP reduction after SLT. Post-SLT expansion of SC may be due to increased trabecular aqueous outflow, IOP decrease, or structural changes in trabecular meshwork resulting from SLT.
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Effect of Cyclopentolate on In Vivo Schlemm Canal Microarchitecture in Healthy Subjects.
Journal of Glaucoma, 2016Co-Authors: Michael S Rosman, Alon Skaat, Jason L Chien, Mark P Ghassibi, Tarela F Sarimiye, Jeffrey M. Liebmann, Robert Ritch, Sung-chul ParkAbstract:PURPOSE: To characterize the in vivo effect of cyclopentolate on the microstructure of Schlemm Canal (SC) in healthy eyes. METHODS: For healthy subjects, 81 serial horizontal enhanced depth imaging optical coherence tomography B-scans (interval between scans, ∼35 μm) of the nasal corneoscleral limbal area were obtained before and 1 hour after cyclopentolate 1% administration in 1 eye. The structures of aqueous and blood vessels in each scan were used as landmarks to select 50 overlapping scans between the 2 sets of 81 serial scans (before and after cyclopentolate administration). The SC cross-sectional area was measured in each of the 50 selected scans. After 3-dimensional reconstruction, SC volume was determined. RESULTS: Twelve eyes (12 healthy subjects) were imaged successfully before and after cyclopentolate administration. Mean age was 27.8±4.9 years (range, 25 to 38 y). Following cyclopentolate administration, mean intraocular pressure did not change significantly (13.9±1.5 to 14.2±1.5 mm Hg; P=0.19). Mean SC cross-sectional area decreased by 17%, from 3563±706 to 2959±460 μm (P
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effect of cyclopentolate on in vivo Schlemm Canal microarchitecture in healthy subjects
Journal of Glaucoma, 2016Co-Authors: Michael S Rosman, Alon Skaat, Jason L Chien, Mark P Ghassibi, Tarela F Sarimiye, Jeffrey M. Liebmann, Robert Ritch, Sung-chul ParkAbstract:PURPOSE: To characterize the in vivo effect of cyclopentolate on the microstructure of Schlemm Canal (SC) in healthy eyes. METHODS: For healthy subjects, 81 serial horizontal enhanced depth imaging optical coherence tomography B-scans (interval between scans, ∼35 μm) of the nasal corneoscleral limbal area were obtained before and 1 hour after cyclopentolate 1% administration in 1 eye. The structures of aqueous and blood vessels in each scan were used as landmarks to select 50 overlapping scans between the 2 sets of 81 serial scans (before and after cyclopentolate administration). The SC cross-sectional area was measured in each of the 50 selected scans. After 3-dimensional reconstruction, SC volume was determined. RESULTS: Twelve eyes (12 healthy subjects) were imaged successfully before and after cyclopentolate administration. Mean age was 27.8±4.9 years (range, 25 to 38 y). Following cyclopentolate administration, mean intraocular pressure did not change significantly (13.9±1.5 to 14.2±1.5 mm Hg; P=0.19). Mean SC cross-sectional area decreased by 17%, from 3563±706 to 2959±460 μm (P<0.001). Mean SC volume in the overlapping area (approximately 1.7 mm of circumferential length of SC) decreased from 6,164,061±1,220,787 to 5,119,462±794,763 μm (P<0.001). The decrease in the mean SC cross-sectional area after cyclopentolate administration was greater in eyes with larger baseline SC cross-sectional area (P<0.001, R=0.873). CONCLUSIONS: Cyclopentolate causes a reduction in SC dimensions in healthy eyes. Future studies are warranted to determine the exact mechanism(s) of this change.
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effect of pilocarpine hydrochloride on the Schlemm Canal in healthy eyes and eyes with open angle glaucoma
JAMA Ophthalmology, 2016Co-Authors: Rachel S Mogil, Alon Skaat, Jason L Chien, Sung-chul Park, Jeffrey M. Liebmann, Robert Ritch, Michael S RosmanAbstract:Importance The in vivo effect of pilocarpine hydrochloride on the Schlemm Canal may help explain its pharmacologic mechanism of action and better indicate its clinical use. Objective To investigate the effect of pilocarpine on the structure of the Schlemm Canal in vivo in healthy eyes and eyes with glaucoma. Design, Setting, and Participants In this case-control study, healthy individuals and patients with open-angle glaucoma were prospectively enrolled between September 1, 2013, and June 30, 2014, after a complete ophthalmologic examination at a tertiary glaucoma referral practice. Eighty-one serial, horizontal, enhanced depth imaging optical coherence tomographic B-scans (interval between B-scans, approximately 35 µm) of the nasal corneoscleral limbus were performed before and 1 hour after topical administration of pilocarpine, 1%, in 1 eye of healthy volunteers and pilocarpine, 2%, in 1 eye of patients with glaucoma. Fifty B-scans in the overlapping area (circumferential length, approximately 1.7 mm) between the 2 sets of serial scans (before and after pilocarpine administration) were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The cross-sectional area of the Schlemm Canal was measured in each selected B-scan. Volume of the Schlemm Canal was calculated using commercially available 3-dimensional reconstruction software. Main Outcomes and Measures Mean cross-sectional area of the Schlemm Canal. Results Enhanced depth imaging optical coherence tomographic scans of the Schlemm Canal were performed successfully before and after administration of pilocarpine, 1%, in 9 healthy eyes (9 individuals) and pilocarpine, 2%, in 10 eyes with glaucoma (10 patients) (mean [SD] age, 31.9 [7.8] and 68.7 [13.2] years, respectively). Following pilocarpine administration, mean (SD) intraocular pressure decreased from 14.3 (1.3) to 13.7 (1.1) mm Hg in healthy eyes ( P = .004) and from 17.5 (6.0) to 16.6 (6.1) mm Hg in eyes with glaucoma ( P = .01). The mean (SD) cross-sectional area of the Schlemm Canal increased by 21% (4667 [1704] to 5647 [1911] µm 2 ) in healthy eyes ( P 2 ) in eyes with glaucoma ( P 3 in healthy eyes ( P 3 in eyes with glaucoma ( P Conclusions and Relevance These data suggest that pilocarpine expands the Schlemm Canal in eyes with and without glaucoma. No differences in the effect were identified between the 2 groups. Enhanced depth imaging optical coherence tomography may be useful in investigating the effect of pharmacologic agents on the Schlemm Canal.
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effect of pilocarpine hydrochloride on the Schlemm Canal in healthy eyes and eyes with open angle glaucoma
JAMA Ophthalmology, 2016Co-Authors: Rachel S Mogil, Alon Skaat, Jason L Chien, Sung-chul Park, Jeffrey M. Liebmann, Robert Ritch, Michael S RosmanAbstract:Importance The in vivo effect of pilocarpine hydrochloride on the Schlemm Canal may help explain its pharmacologic mechanism of action and better indicate its clinical use. Objective To investigate the effect of pilocarpine on the structure of the Schlemm Canal in vivo in healthy eyes and eyes with glaucoma. Design, Setting, and Participants In this case-control study, healthy individuals and patients with open-angle glaucoma were prospectively enrolled between September 1, 2013, and June 30, 2014, after a complete ophthalmologic examination at a tertiary glaucoma referral practice. Eighty-one serial, horizontal, enhanced depth imaging optical coherence tomographic B-scans (interval between B-scans, approximately 35 µm) of the nasal corneoscleral limbus were performed before and 1 hour after topical administration of pilocarpine, 1%, in 1 eye of healthy volunteers and pilocarpine, 2%, in 1 eye of patients with glaucoma. Fifty B-scans in the overlapping area (circumferential length, approximately 1.7 mm) between the 2 sets of serial scans (before and after pilocarpine administration) were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The cross-sectional area of the Schlemm Canal was measured in each selected B-scan. Volume of the Schlemm Canal was calculated using commercially available 3-dimensional reconstruction software. Main Outcomes and Measures Mean cross-sectional area of the Schlemm Canal. Results Enhanced depth imaging optical coherence tomographic scans of the Schlemm Canal were performed successfully before and after administration of pilocarpine, 1%, in 9 healthy eyes (9 individuals) and pilocarpine, 2%, in 10 eyes with glaucoma (10 patients) (mean [SD] age, 31.9 [7.8] and 68.7 [13.2] years, respectively). Following pilocarpine administration, mean (SD) intraocular pressure decreased from 14.3 (1.3) to 13.7 (1.1) mm Hg in healthy eyes ( P = .004) and from 17.5 (6.0) to 16.6 (6.1) mm Hg in eyes with glaucoma ( P = .01). The mean (SD) cross-sectional area of the Schlemm Canal increased by 21% (4667 [1704] to 5647 [1911] µm 2 ) in healthy eyes ( P 2 ) in eyes with glaucoma ( P 3 in healthy eyes ( P 3 in eyes with glaucoma ( P Conclusions and Relevance These data suggest that pilocarpine expands the Schlemm Canal in eyes with and without glaucoma. No differences in the effect were identified between the 2 groups. Enhanced depth imaging optical coherence tomography may be useful in investigating the effect of pharmacologic agents on the Schlemm Canal.
Alon Skaat - One of the best experts on this subject based on the ideXlab platform.
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microarchitecture of Schlemm Canal before and after selective laser trabeculoplasty in enhanced depth imaging optical coherence tomography
Journal of Glaucoma, 2017Co-Authors: Alon Skaat, Jason L Chien, Mark P Ghassibi, Jeffrey M. Liebmann, Robert Ritch, Michael S Rosman, Sung-chul ParkAbstract:PURPOSE To characterize the in vivo effect of selective laser trabeculoplasty (SLT) on the Schlemm Canal (SC) in eyes with primary open-angle glaucoma (POAG). MATERIALS AND METHODS Eighty-one serial horizontal enhanced depth imaging optical coherence tomograph B-scans (interval between B-scans, ∼35 μm) of the nasal corneoscleral limbus were obtained before and 4 weeks after SLT. Fifty B-scans in the overlapping regions before and after SLT were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The SC cross-sectional area (CSA) was measured in each selected B-scan and averaged to generate the mean SC CSA of the eye. SC volume in the overlapping region was calculated using commercially available 3-dimensional reconstruction software. The mean SC CSA and SC volume were compared between pre-SLT and post-SLT B-scans. Correlation analysis was performed between SC CSA changes and intraocular pressure (IOP) changes. RESULTS Thirteen POAG eyes (13 patients) were included for analysis (mean age, 68.2±9.2 y). After SLT, the mean IOP was reduced from 19.8±7.6 to 14.4±3.8 mm Hg (P=0.003); the mean SC CSA increased by 8%, from 2478±550 to 2682±598 μm (P=0.029); and the mean SC volume increased from 4,304,592±954,777 to 4,658,250±1,039,956 μm (P=0.029). Increase in SC CSA had a significant positive correlation with IOP reduction after SLT (P=0.023, R=0.622). CONCLUSIONS SLT expands SC in POAG patients and even more so with greater IOP reduction after SLT. Post-SLT expansion of SC may be due to increased trabecular aqueous outflow, IOP decrease, or structural changes in trabecular meshwork resulting from SLT.
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Effect of Cyclopentolate on In Vivo Schlemm Canal Microarchitecture in Healthy Subjects.
Journal of Glaucoma, 2016Co-Authors: Michael S Rosman, Alon Skaat, Jason L Chien, Mark P Ghassibi, Tarela F Sarimiye, Jeffrey M. Liebmann, Robert Ritch, Sung-chul ParkAbstract:PURPOSE: To characterize the in vivo effect of cyclopentolate on the microstructure of Schlemm Canal (SC) in healthy eyes. METHODS: For healthy subjects, 81 serial horizontal enhanced depth imaging optical coherence tomography B-scans (interval between scans, ∼35 μm) of the nasal corneoscleral limbal area were obtained before and 1 hour after cyclopentolate 1% administration in 1 eye. The structures of aqueous and blood vessels in each scan were used as landmarks to select 50 overlapping scans between the 2 sets of 81 serial scans (before and after cyclopentolate administration). The SC cross-sectional area was measured in each of the 50 selected scans. After 3-dimensional reconstruction, SC volume was determined. RESULTS: Twelve eyes (12 healthy subjects) were imaged successfully before and after cyclopentolate administration. Mean age was 27.8±4.9 years (range, 25 to 38 y). Following cyclopentolate administration, mean intraocular pressure did not change significantly (13.9±1.5 to 14.2±1.5 mm Hg; P=0.19). Mean SC cross-sectional area decreased by 17%, from 3563±706 to 2959±460 μm (P
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effect of cyclopentolate on in vivo Schlemm Canal microarchitecture in healthy subjects
Journal of Glaucoma, 2016Co-Authors: Michael S Rosman, Alon Skaat, Jason L Chien, Mark P Ghassibi, Tarela F Sarimiye, Jeffrey M. Liebmann, Robert Ritch, Sung-chul ParkAbstract:PURPOSE: To characterize the in vivo effect of cyclopentolate on the microstructure of Schlemm Canal (SC) in healthy eyes. METHODS: For healthy subjects, 81 serial horizontal enhanced depth imaging optical coherence tomography B-scans (interval between scans, ∼35 μm) of the nasal corneoscleral limbal area were obtained before and 1 hour after cyclopentolate 1% administration in 1 eye. The structures of aqueous and blood vessels in each scan were used as landmarks to select 50 overlapping scans between the 2 sets of 81 serial scans (before and after cyclopentolate administration). The SC cross-sectional area was measured in each of the 50 selected scans. After 3-dimensional reconstruction, SC volume was determined. RESULTS: Twelve eyes (12 healthy subjects) were imaged successfully before and after cyclopentolate administration. Mean age was 27.8±4.9 years (range, 25 to 38 y). Following cyclopentolate administration, mean intraocular pressure did not change significantly (13.9±1.5 to 14.2±1.5 mm Hg; P=0.19). Mean SC cross-sectional area decreased by 17%, from 3563±706 to 2959±460 μm (P<0.001). Mean SC volume in the overlapping area (approximately 1.7 mm of circumferential length of SC) decreased from 6,164,061±1,220,787 to 5,119,462±794,763 μm (P<0.001). The decrease in the mean SC cross-sectional area after cyclopentolate administration was greater in eyes with larger baseline SC cross-sectional area (P<0.001, R=0.873). CONCLUSIONS: Cyclopentolate causes a reduction in SC dimensions in healthy eyes. Future studies are warranted to determine the exact mechanism(s) of this change.
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effect of pilocarpine hydrochloride on the Schlemm Canal in healthy eyes and eyes with open angle glaucoma
JAMA Ophthalmology, 2016Co-Authors: Rachel S Mogil, Alon Skaat, Jason L Chien, Sung-chul Park, Jeffrey M. Liebmann, Robert Ritch, Michael S RosmanAbstract:Importance The in vivo effect of pilocarpine hydrochloride on the Schlemm Canal may help explain its pharmacologic mechanism of action and better indicate its clinical use. Objective To investigate the effect of pilocarpine on the structure of the Schlemm Canal in vivo in healthy eyes and eyes with glaucoma. Design, Setting, and Participants In this case-control study, healthy individuals and patients with open-angle glaucoma were prospectively enrolled between September 1, 2013, and June 30, 2014, after a complete ophthalmologic examination at a tertiary glaucoma referral practice. Eighty-one serial, horizontal, enhanced depth imaging optical coherence tomographic B-scans (interval between B-scans, approximately 35 µm) of the nasal corneoscleral limbus were performed before and 1 hour after topical administration of pilocarpine, 1%, in 1 eye of healthy volunteers and pilocarpine, 2%, in 1 eye of patients with glaucoma. Fifty B-scans in the overlapping area (circumferential length, approximately 1.7 mm) between the 2 sets of serial scans (before and after pilocarpine administration) were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The cross-sectional area of the Schlemm Canal was measured in each selected B-scan. Volume of the Schlemm Canal was calculated using commercially available 3-dimensional reconstruction software. Main Outcomes and Measures Mean cross-sectional area of the Schlemm Canal. Results Enhanced depth imaging optical coherence tomographic scans of the Schlemm Canal were performed successfully before and after administration of pilocarpine, 1%, in 9 healthy eyes (9 individuals) and pilocarpine, 2%, in 10 eyes with glaucoma (10 patients) (mean [SD] age, 31.9 [7.8] and 68.7 [13.2] years, respectively). Following pilocarpine administration, mean (SD) intraocular pressure decreased from 14.3 (1.3) to 13.7 (1.1) mm Hg in healthy eyes ( P = .004) and from 17.5 (6.0) to 16.6 (6.1) mm Hg in eyes with glaucoma ( P = .01). The mean (SD) cross-sectional area of the Schlemm Canal increased by 21% (4667 [1704] to 5647 [1911] µm 2 ) in healthy eyes ( P 2 ) in eyes with glaucoma ( P 3 in healthy eyes ( P 3 in eyes with glaucoma ( P Conclusions and Relevance These data suggest that pilocarpine expands the Schlemm Canal in eyes with and without glaucoma. No differences in the effect were identified between the 2 groups. Enhanced depth imaging optical coherence tomography may be useful in investigating the effect of pharmacologic agents on the Schlemm Canal.
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effect of pilocarpine hydrochloride on the Schlemm Canal in healthy eyes and eyes with open angle glaucoma
JAMA Ophthalmology, 2016Co-Authors: Rachel S Mogil, Alon Skaat, Jason L Chien, Sung-chul Park, Jeffrey M. Liebmann, Robert Ritch, Michael S RosmanAbstract:Importance The in vivo effect of pilocarpine hydrochloride on the Schlemm Canal may help explain its pharmacologic mechanism of action and better indicate its clinical use. Objective To investigate the effect of pilocarpine on the structure of the Schlemm Canal in vivo in healthy eyes and eyes with glaucoma. Design, Setting, and Participants In this case-control study, healthy individuals and patients with open-angle glaucoma were prospectively enrolled between September 1, 2013, and June 30, 2014, after a complete ophthalmologic examination at a tertiary glaucoma referral practice. Eighty-one serial, horizontal, enhanced depth imaging optical coherence tomographic B-scans (interval between B-scans, approximately 35 µm) of the nasal corneoscleral limbus were performed before and 1 hour after topical administration of pilocarpine, 1%, in 1 eye of healthy volunteers and pilocarpine, 2%, in 1 eye of patients with glaucoma. Fifty B-scans in the overlapping area (circumferential length, approximately 1.7 mm) between the 2 sets of serial scans (before and after pilocarpine administration) were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The cross-sectional area of the Schlemm Canal was measured in each selected B-scan. Volume of the Schlemm Canal was calculated using commercially available 3-dimensional reconstruction software. Main Outcomes and Measures Mean cross-sectional area of the Schlemm Canal. Results Enhanced depth imaging optical coherence tomographic scans of the Schlemm Canal were performed successfully before and after administration of pilocarpine, 1%, in 9 healthy eyes (9 individuals) and pilocarpine, 2%, in 10 eyes with glaucoma (10 patients) (mean [SD] age, 31.9 [7.8] and 68.7 [13.2] years, respectively). Following pilocarpine administration, mean (SD) intraocular pressure decreased from 14.3 (1.3) to 13.7 (1.1) mm Hg in healthy eyes ( P = .004) and from 17.5 (6.0) to 16.6 (6.1) mm Hg in eyes with glaucoma ( P = .01). The mean (SD) cross-sectional area of the Schlemm Canal increased by 21% (4667 [1704] to 5647 [1911] µm 2 ) in healthy eyes ( P 2 ) in eyes with glaucoma ( P 3 in healthy eyes ( P 3 in eyes with glaucoma ( P Conclusions and Relevance These data suggest that pilocarpine expands the Schlemm Canal in eyes with and without glaucoma. No differences in the effect were identified between the 2 groups. Enhanced depth imaging optical coherence tomography may be useful in investigating the effect of pharmacologic agents on the Schlemm Canal.
Thomas W Samuelson - One of the best experts on this subject based on the ideXlab platform.
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three year findings of the horizon trial a Schlemm Canal microstent for pressure reduction in primary open angle glaucoma and cataract
Ophthalmology, 2020Co-Authors: Iqbal Ike K Ahmed, Thomas W Samuelson, Kuldev Singh, Jason Jones, Douglas J Rhee, Inder Paul Singh, Nathan M Radcliffe, Gus Gazzard, Jeb Ong, Horizon InvestigatorsAbstract:Purpose To report 3-year outcomes of the HORIZON study comparing cataract surgery (CS) with Hydrus Microstent (Ivantis, Inc) implantation versus CS alone. Design Multicenter randomized clinical trial. Participants Five hundred fifty-six eyes from 556 patients with cataract and primary open-angle glaucoma (POAG) treated with 1 or more glaucoma medication, washed out diurnal intraocular pressure (IOP) of 22 to 34 mmHg, and no prior incisional glaucoma surgery. Methods After phacoemulsification, eyes were randomized 2:1 to receive a Hydrus Microstent or no stent. Follow-up included comprehensive eye examinations through 3 years. Main Outcome Measures Outcome measures included IOP, medical therapy, reoperation rates, visual acuity, adverse events, and changes in corneal endothelial cell counts. Results Three hundred sixty-nine eyes were randomized to microstent treatment and 187 to CS only. Preoperative IOP, medication use, washed-out diurnal IOP, and glaucoma severity did not differ between the two treatment groups. At 3 years, IOP was 16.7 ± 3.1 mmHg in the microstent group and 17.0 ± 3.4 mmHg in the CS group (P = 0.85). The number of glaucoma medications was 0.4 ± 0.8 in the microstent group and 0.8 ± 1.0 in the CS group (P Conclusions Combined CS and microstent placement for mild to moderate POAG is safe, more effective in lowering IOP with fewer medications, and less likely to result in further incisional glaucoma filtration surgery than CS alone at 3 years.
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results from the united states cohort of the horizon trial of a Schlemm Canal microstent to reduce intraocular pressure in primary open angle glaucoma
Journal of Cataract and Refractive Surgery, 2019Co-Authors: Jason Jones, Richard A Lewis, Thomas W Samuelson, Douglas D Koch, Steven D Vold, Cathleen M Mccabe, Douglas J Rhee, S A Smith, Quang H Nguyen, Thomas R WaltersAbstract:Purpose To assess the safety and effectiveness of Schlemm Canal stenting for reducing intraocular pressure (IOP) in combination with cataract surgery in the United States cohort of the HORIZON study. Setting Twenty-six clinical sites in the U.S. Design Prospective clinical trial. Methods Eyes with mild to moderate primary open-angle glaucoma (POAG) on 1 to 4 medications, significant cataract, and an unmedicated diurnal IOP between 22 mm Hg and 34 mm Hg after medication washout were randomized 2:1 to receive the Hydrus microstent or no further treatment after successful cataract surgery. Patients were followed for 24 months. Medication washout and diurnal IOP measurements were repeated at 12 months and 24 months. Results Two hundred nineteen eyes were randomized to microstent implantation and 112 patients to phacoemulsification only. At 24 months, the diurnal IOP was reduced by 20.0% or more in a greater proportion of eyes in the microstent group (78.5% versus 54.5%; P Conclusions Implantation of a Schlemm Canal microstent after phacoemulsification significantly reduced diurnal IOP and medication use compared with phacoemulsification only in patients with mild to moderately severe POAG. The combination procedure was equivalent to cataract surgery alone in terms of visual acuity outcomes and the rate of adverse ocular events.
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a Schlemm Canal microstent for intraocular pressure reduction in primary open angle glaucoma and cataract the horizon study
Ophthalmology, 2019Co-Authors: Thomas W Samuelson, David F Chang, Robert Marquis, Brian Flowers, Sheng K Lim, Iqbal Ike K Ahmed, Henry D Jampel, Tin Aung, Alan S Crandall, Kuldev SinghAbstract:Objective To compare cataract surgery with implantation of a Schlemm Canal microstent with cataract surgery alone for the reduction of intraocular pressure (IOP) and medication use after 24 months. Design Prospective, multicenter, single-masked, randomized controlled trial. Participants Subjects with concomitant primary open-angle glaucoma (POAG), visually significant cataract, and washed-out modified diurnal IOP (MDIOP) between 22 and 34 mmHg. Methods Subjects were randomized 2:1 to receive a single Hydrus Microstent (Ivantis, Inc, Irvine, CA) in the Schlemm Canal or no stent after uncomplicated phacoemulsification. Comprehensive eye examinations were conducted 1 day, 1 week, and 1, 3, 6, 12, 18, and 24 months postoperatively. Medication washout and MDIOP measurement were repeated at 12 and 24 months. Main Outcome Measures The primary and secondary effectiveness end points were the proportion of subjects demonstrating a 20% or greater reduction in unmedicated MDIOP and change in mean MDIOP from baseline at 24 months, respectively. Hypotensive medication use was tracked throughout the course of follow-up. Safety measures included the frequency of surgical complications and adverse events. Results A total of 369 eyes were randomized after phacoemulsification to Hydrus Microstent (HMS) and 187 to no microstent (NMS). At 24 months, unmedicated MDIOP was reduced by ≥20% in 77.3% of HMS group eyes and in 57.8% of NMS group eyes (difference = 19.5%, 95% confidence interval [CI] 11.2%–27.8%, P Conclusions This 24-month multicenter randomized controlled trial demonstrated superior reduction in MDIOP and medication use among subjects with mild-to-moderate POAG who received a Schlemm Canal microstent combined with phacoemulsification compared with phacoemulsification alone.
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effects of a Schlemm Canal scaffold on collector channel ostia in human anterior segments
Experimental Eye Research, 2014Co-Authors: Murray A Johnstone, Thomas W Samuelson, Iqbal Ike K Ahmed, Andrew T Schieber, Hady Saheb, Carol B TorisAbstract:This study evaluates the morphologic effect of the implantation of two different sizes of the Hydrus microstent on the outer wall of Schlemm's Canal (SC) and collector channel (CC) ostia. Twelve human eyes were dissected at the equator removing the iris, lens, ciliary body and vitreous. The cornea was excised with a corneal trephine exposing a direct view of the angle while leaving the trabecular meshwork (TM) intact. The Hydrus delivery system was used to deliver microstents of 8 mm and 15 mm in length into SC. Following delivery, the tissues were immediately immersed in fixative. After tissue fixation, the microstents were gently lifted out of SC through the TM leaving a small slit opening in the TM. The slit opening was widened by gently dissecting the entire TM. Control eyes underwent dissection before fixation by gently removing the TM exposing the outer wall of SC. The tissues were prepared for scanning electron microscopy (SEM). The external wall of SC was imaged using SEM and were reviewed with particular attention focused on the distribution of irregular particulate matter (IPM), the shape of the CC ostia and the health of the SC endothelium. Three eyes received the 8 mm microstent, two the 15 mm microstent and 6 eyes served as controls. Five of the controls had reported histories of glaucoma while all other eyes were normal. All eyes showed evidence of removal of the trabecular meshwork revealing the external wall of SC. CCs were regularly visible in all eyes and were not obstructed, compressed or their margins disrupted. Nuclear profiles were oriented circumferentially in SC except at regions of CC ostia where they assumed a radial configuration oriented toward the lumen of the CC. The area of microstent contact with SC external wall was examined with SEM and a comparison made between the 8 and 15 mm microstent showing a smaller area of indentation with the 8 mm microstent. The indentations were generally free of particulate debris, were smooth and were devoid of nuclear profiles. In bridged areas adjacent to areas of microstent contact, CCs were identified, appearing patent and intact like those of the control eyes. The eyes receiving 8 mm and 15 mm Hydrus microstents both maintained CC ostia patency but a smaller area of external wall contact was evident from insertion of the 8 mm microstent.
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Canaloplasty three year results of circumferential viscodilation and tensioning of Schlemm Canal using a microcatheter to treat open angle glaucoma
Journal of Cataract and Refractive Surgery, 2011Co-Authors: Richard A Lewis, Norbert Koerber, Kurt Von Wolff, Manfred Tetz, John R Kearney, Bradford J Shingleton, Thomas W SamuelsonAbstract:Purpose To report 3-year results of the safety and efficacy of Canaloplasty, a procedure involving circumferential viscodilation and tensioning of the inner wall of Schlemm Canal to treat open-angle glaucoma. Setting Multicenter surgical sites. Design Nonrandomized multicenter clinical trial. Methods This study comprised adult open-angle glaucoma patients having Canaloplasty or combined cataract–Canaloplasty surgery. Qualifying preoperative intraocular pressures (IOPs) were at least 16 mm Hg with historical IOPs of at least 21 mm Hg. A flexible microcatheter was used to viscodilate the full circumference of the Canal and to place a trabecular tensioning suture. Primary outcome measures included IOP, glaucoma medication use, and adverse events. Results Three years postoperatively, all study eyes (n = 157) had a mean IOP of 15.2 mm Hg ± 3.5 (SD) and mean glaucoma medication use of 0.8 ± 0.9 compared with a baseline IOP of 23.8 ± 5.0 mm Hg on 1.8 ± 0.9 medications. Eyes with combined cataract–Canaloplasty surgery had a mean IOP of 13.6 ± 3.6 mm Hg on 0.3 ± 0.5 medications compared with a baseline IOP of 23.5 ± 5.2 mm Hg on 1.5 ± 1.0 medications. Intraocular pressure and medication use results in all eyes were significantly decreased from baseline at every time point ( P Conclusion Canaloplasty led to a significant and sustained IOP reduction in adult patients with open-angle glaucoma and had an excellent short- and long-term postoperative safety profile. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.
Michael S Rosman - One of the best experts on this subject based on the ideXlab platform.
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microarchitecture of Schlemm Canal before and after selective laser trabeculoplasty in enhanced depth imaging optical coherence tomography
Journal of Glaucoma, 2017Co-Authors: Alon Skaat, Jason L Chien, Mark P Ghassibi, Jeffrey M. Liebmann, Robert Ritch, Michael S Rosman, Sung-chul ParkAbstract:PURPOSE To characterize the in vivo effect of selective laser trabeculoplasty (SLT) on the Schlemm Canal (SC) in eyes with primary open-angle glaucoma (POAG). MATERIALS AND METHODS Eighty-one serial horizontal enhanced depth imaging optical coherence tomograph B-scans (interval between B-scans, ∼35 μm) of the nasal corneoscleral limbus were obtained before and 4 weeks after SLT. Fifty B-scans in the overlapping regions before and after SLT were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The SC cross-sectional area (CSA) was measured in each selected B-scan and averaged to generate the mean SC CSA of the eye. SC volume in the overlapping region was calculated using commercially available 3-dimensional reconstruction software. The mean SC CSA and SC volume were compared between pre-SLT and post-SLT B-scans. Correlation analysis was performed between SC CSA changes and intraocular pressure (IOP) changes. RESULTS Thirteen POAG eyes (13 patients) were included for analysis (mean age, 68.2±9.2 y). After SLT, the mean IOP was reduced from 19.8±7.6 to 14.4±3.8 mm Hg (P=0.003); the mean SC CSA increased by 8%, from 2478±550 to 2682±598 μm (P=0.029); and the mean SC volume increased from 4,304,592±954,777 to 4,658,250±1,039,956 μm (P=0.029). Increase in SC CSA had a significant positive correlation with IOP reduction after SLT (P=0.023, R=0.622). CONCLUSIONS SLT expands SC in POAG patients and even more so with greater IOP reduction after SLT. Post-SLT expansion of SC may be due to increased trabecular aqueous outflow, IOP decrease, or structural changes in trabecular meshwork resulting from SLT.
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Effect of Cyclopentolate on In Vivo Schlemm Canal Microarchitecture in Healthy Subjects.
Journal of Glaucoma, 2016Co-Authors: Michael S Rosman, Alon Skaat, Jason L Chien, Mark P Ghassibi, Tarela F Sarimiye, Jeffrey M. Liebmann, Robert Ritch, Sung-chul ParkAbstract:PURPOSE: To characterize the in vivo effect of cyclopentolate on the microstructure of Schlemm Canal (SC) in healthy eyes. METHODS: For healthy subjects, 81 serial horizontal enhanced depth imaging optical coherence tomography B-scans (interval between scans, ∼35 μm) of the nasal corneoscleral limbal area were obtained before and 1 hour after cyclopentolate 1% administration in 1 eye. The structures of aqueous and blood vessels in each scan were used as landmarks to select 50 overlapping scans between the 2 sets of 81 serial scans (before and after cyclopentolate administration). The SC cross-sectional area was measured in each of the 50 selected scans. After 3-dimensional reconstruction, SC volume was determined. RESULTS: Twelve eyes (12 healthy subjects) were imaged successfully before and after cyclopentolate administration. Mean age was 27.8±4.9 years (range, 25 to 38 y). Following cyclopentolate administration, mean intraocular pressure did not change significantly (13.9±1.5 to 14.2±1.5 mm Hg; P=0.19). Mean SC cross-sectional area decreased by 17%, from 3563±706 to 2959±460 μm (P
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effect of cyclopentolate on in vivo Schlemm Canal microarchitecture in healthy subjects
Journal of Glaucoma, 2016Co-Authors: Michael S Rosman, Alon Skaat, Jason L Chien, Mark P Ghassibi, Tarela F Sarimiye, Jeffrey M. Liebmann, Robert Ritch, Sung-chul ParkAbstract:PURPOSE: To characterize the in vivo effect of cyclopentolate on the microstructure of Schlemm Canal (SC) in healthy eyes. METHODS: For healthy subjects, 81 serial horizontal enhanced depth imaging optical coherence tomography B-scans (interval between scans, ∼35 μm) of the nasal corneoscleral limbal area were obtained before and 1 hour after cyclopentolate 1% administration in 1 eye. The structures of aqueous and blood vessels in each scan were used as landmarks to select 50 overlapping scans between the 2 sets of 81 serial scans (before and after cyclopentolate administration). The SC cross-sectional area was measured in each of the 50 selected scans. After 3-dimensional reconstruction, SC volume was determined. RESULTS: Twelve eyes (12 healthy subjects) were imaged successfully before and after cyclopentolate administration. Mean age was 27.8±4.9 years (range, 25 to 38 y). Following cyclopentolate administration, mean intraocular pressure did not change significantly (13.9±1.5 to 14.2±1.5 mm Hg; P=0.19). Mean SC cross-sectional area decreased by 17%, from 3563±706 to 2959±460 μm (P<0.001). Mean SC volume in the overlapping area (approximately 1.7 mm of circumferential length of SC) decreased from 6,164,061±1,220,787 to 5,119,462±794,763 μm (P<0.001). The decrease in the mean SC cross-sectional area after cyclopentolate administration was greater in eyes with larger baseline SC cross-sectional area (P<0.001, R=0.873). CONCLUSIONS: Cyclopentolate causes a reduction in SC dimensions in healthy eyes. Future studies are warranted to determine the exact mechanism(s) of this change.
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effect of pilocarpine hydrochloride on the Schlemm Canal in healthy eyes and eyes with open angle glaucoma
JAMA Ophthalmology, 2016Co-Authors: Rachel S Mogil, Alon Skaat, Jason L Chien, Sung-chul Park, Jeffrey M. Liebmann, Robert Ritch, Michael S RosmanAbstract:Importance The in vivo effect of pilocarpine hydrochloride on the Schlemm Canal may help explain its pharmacologic mechanism of action and better indicate its clinical use. Objective To investigate the effect of pilocarpine on the structure of the Schlemm Canal in vivo in healthy eyes and eyes with glaucoma. Design, Setting, and Participants In this case-control study, healthy individuals and patients with open-angle glaucoma were prospectively enrolled between September 1, 2013, and June 30, 2014, after a complete ophthalmologic examination at a tertiary glaucoma referral practice. Eighty-one serial, horizontal, enhanced depth imaging optical coherence tomographic B-scans (interval between B-scans, approximately 35 µm) of the nasal corneoscleral limbus were performed before and 1 hour after topical administration of pilocarpine, 1%, in 1 eye of healthy volunteers and pilocarpine, 2%, in 1 eye of patients with glaucoma. Fifty B-scans in the overlapping area (circumferential length, approximately 1.7 mm) between the 2 sets of serial scans (before and after pilocarpine administration) were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The cross-sectional area of the Schlemm Canal was measured in each selected B-scan. Volume of the Schlemm Canal was calculated using commercially available 3-dimensional reconstruction software. Main Outcomes and Measures Mean cross-sectional area of the Schlemm Canal. Results Enhanced depth imaging optical coherence tomographic scans of the Schlemm Canal were performed successfully before and after administration of pilocarpine, 1%, in 9 healthy eyes (9 individuals) and pilocarpine, 2%, in 10 eyes with glaucoma (10 patients) (mean [SD] age, 31.9 [7.8] and 68.7 [13.2] years, respectively). Following pilocarpine administration, mean (SD) intraocular pressure decreased from 14.3 (1.3) to 13.7 (1.1) mm Hg in healthy eyes ( P = .004) and from 17.5 (6.0) to 16.6 (6.1) mm Hg in eyes with glaucoma ( P = .01). The mean (SD) cross-sectional area of the Schlemm Canal increased by 21% (4667 [1704] to 5647 [1911] µm 2 ) in healthy eyes ( P 2 ) in eyes with glaucoma ( P 3 in healthy eyes ( P 3 in eyes with glaucoma ( P Conclusions and Relevance These data suggest that pilocarpine expands the Schlemm Canal in eyes with and without glaucoma. No differences in the effect were identified between the 2 groups. Enhanced depth imaging optical coherence tomography may be useful in investigating the effect of pharmacologic agents on the Schlemm Canal.
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effect of pilocarpine hydrochloride on the Schlemm Canal in healthy eyes and eyes with open angle glaucoma
JAMA Ophthalmology, 2016Co-Authors: Rachel S Mogil, Alon Skaat, Jason L Chien, Sung-chul Park, Jeffrey M. Liebmann, Robert Ritch, Michael S RosmanAbstract:Importance The in vivo effect of pilocarpine hydrochloride on the Schlemm Canal may help explain its pharmacologic mechanism of action and better indicate its clinical use. Objective To investigate the effect of pilocarpine on the structure of the Schlemm Canal in vivo in healthy eyes and eyes with glaucoma. Design, Setting, and Participants In this case-control study, healthy individuals and patients with open-angle glaucoma were prospectively enrolled between September 1, 2013, and June 30, 2014, after a complete ophthalmologic examination at a tertiary glaucoma referral practice. Eighty-one serial, horizontal, enhanced depth imaging optical coherence tomographic B-scans (interval between B-scans, approximately 35 µm) of the nasal corneoscleral limbus were performed before and 1 hour after topical administration of pilocarpine, 1%, in 1 eye of healthy volunteers and pilocarpine, 2%, in 1 eye of patients with glaucoma. Fifty B-scans in the overlapping area (circumferential length, approximately 1.7 mm) between the 2 sets of serial scans (before and after pilocarpine administration) were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The cross-sectional area of the Schlemm Canal was measured in each selected B-scan. Volume of the Schlemm Canal was calculated using commercially available 3-dimensional reconstruction software. Main Outcomes and Measures Mean cross-sectional area of the Schlemm Canal. Results Enhanced depth imaging optical coherence tomographic scans of the Schlemm Canal were performed successfully before and after administration of pilocarpine, 1%, in 9 healthy eyes (9 individuals) and pilocarpine, 2%, in 10 eyes with glaucoma (10 patients) (mean [SD] age, 31.9 [7.8] and 68.7 [13.2] years, respectively). Following pilocarpine administration, mean (SD) intraocular pressure decreased from 14.3 (1.3) to 13.7 (1.1) mm Hg in healthy eyes ( P = .004) and from 17.5 (6.0) to 16.6 (6.1) mm Hg in eyes with glaucoma ( P = .01). The mean (SD) cross-sectional area of the Schlemm Canal increased by 21% (4667 [1704] to 5647 [1911] µm 2 ) in healthy eyes ( P 2 ) in eyes with glaucoma ( P 3 in healthy eyes ( P 3 in eyes with glaucoma ( P Conclusions and Relevance These data suggest that pilocarpine expands the Schlemm Canal in eyes with and without glaucoma. No differences in the effect were identified between the 2 groups. Enhanced depth imaging optical coherence tomography may be useful in investigating the effect of pharmacologic agents on the Schlemm Canal.
Jason L Chien - One of the best experts on this subject based on the ideXlab platform.
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microarchitecture of Schlemm Canal before and after selective laser trabeculoplasty in enhanced depth imaging optical coherence tomography
Journal of Glaucoma, 2017Co-Authors: Alon Skaat, Jason L Chien, Mark P Ghassibi, Jeffrey M. Liebmann, Robert Ritch, Michael S Rosman, Sung-chul ParkAbstract:PURPOSE To characterize the in vivo effect of selective laser trabeculoplasty (SLT) on the Schlemm Canal (SC) in eyes with primary open-angle glaucoma (POAG). MATERIALS AND METHODS Eighty-one serial horizontal enhanced depth imaging optical coherence tomograph B-scans (interval between B-scans, ∼35 μm) of the nasal corneoscleral limbus were obtained before and 4 weeks after SLT. Fifty B-scans in the overlapping regions before and after SLT were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The SC cross-sectional area (CSA) was measured in each selected B-scan and averaged to generate the mean SC CSA of the eye. SC volume in the overlapping region was calculated using commercially available 3-dimensional reconstruction software. The mean SC CSA and SC volume were compared between pre-SLT and post-SLT B-scans. Correlation analysis was performed between SC CSA changes and intraocular pressure (IOP) changes. RESULTS Thirteen POAG eyes (13 patients) were included for analysis (mean age, 68.2±9.2 y). After SLT, the mean IOP was reduced from 19.8±7.6 to 14.4±3.8 mm Hg (P=0.003); the mean SC CSA increased by 8%, from 2478±550 to 2682±598 μm (P=0.029); and the mean SC volume increased from 4,304,592±954,777 to 4,658,250±1,039,956 μm (P=0.029). Increase in SC CSA had a significant positive correlation with IOP reduction after SLT (P=0.023, R=0.622). CONCLUSIONS SLT expands SC in POAG patients and even more so with greater IOP reduction after SLT. Post-SLT expansion of SC may be due to increased trabecular aqueous outflow, IOP decrease, or structural changes in trabecular meshwork resulting from SLT.
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Effect of Cyclopentolate on In Vivo Schlemm Canal Microarchitecture in Healthy Subjects.
Journal of Glaucoma, 2016Co-Authors: Michael S Rosman, Alon Skaat, Jason L Chien, Mark P Ghassibi, Tarela F Sarimiye, Jeffrey M. Liebmann, Robert Ritch, Sung-chul ParkAbstract:PURPOSE: To characterize the in vivo effect of cyclopentolate on the microstructure of Schlemm Canal (SC) in healthy eyes. METHODS: For healthy subjects, 81 serial horizontal enhanced depth imaging optical coherence tomography B-scans (interval between scans, ∼35 μm) of the nasal corneoscleral limbal area were obtained before and 1 hour after cyclopentolate 1% administration in 1 eye. The structures of aqueous and blood vessels in each scan were used as landmarks to select 50 overlapping scans between the 2 sets of 81 serial scans (before and after cyclopentolate administration). The SC cross-sectional area was measured in each of the 50 selected scans. After 3-dimensional reconstruction, SC volume was determined. RESULTS: Twelve eyes (12 healthy subjects) were imaged successfully before and after cyclopentolate administration. Mean age was 27.8±4.9 years (range, 25 to 38 y). Following cyclopentolate administration, mean intraocular pressure did not change significantly (13.9±1.5 to 14.2±1.5 mm Hg; P=0.19). Mean SC cross-sectional area decreased by 17%, from 3563±706 to 2959±460 μm (P
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effect of cyclopentolate on in vivo Schlemm Canal microarchitecture in healthy subjects
Journal of Glaucoma, 2016Co-Authors: Michael S Rosman, Alon Skaat, Jason L Chien, Mark P Ghassibi, Tarela F Sarimiye, Jeffrey M. Liebmann, Robert Ritch, Sung-chul ParkAbstract:PURPOSE: To characterize the in vivo effect of cyclopentolate on the microstructure of Schlemm Canal (SC) in healthy eyes. METHODS: For healthy subjects, 81 serial horizontal enhanced depth imaging optical coherence tomography B-scans (interval between scans, ∼35 μm) of the nasal corneoscleral limbal area were obtained before and 1 hour after cyclopentolate 1% administration in 1 eye. The structures of aqueous and blood vessels in each scan were used as landmarks to select 50 overlapping scans between the 2 sets of 81 serial scans (before and after cyclopentolate administration). The SC cross-sectional area was measured in each of the 50 selected scans. After 3-dimensional reconstruction, SC volume was determined. RESULTS: Twelve eyes (12 healthy subjects) were imaged successfully before and after cyclopentolate administration. Mean age was 27.8±4.9 years (range, 25 to 38 y). Following cyclopentolate administration, mean intraocular pressure did not change significantly (13.9±1.5 to 14.2±1.5 mm Hg; P=0.19). Mean SC cross-sectional area decreased by 17%, from 3563±706 to 2959±460 μm (P<0.001). Mean SC volume in the overlapping area (approximately 1.7 mm of circumferential length of SC) decreased from 6,164,061±1,220,787 to 5,119,462±794,763 μm (P<0.001). The decrease in the mean SC cross-sectional area after cyclopentolate administration was greater in eyes with larger baseline SC cross-sectional area (P<0.001, R=0.873). CONCLUSIONS: Cyclopentolate causes a reduction in SC dimensions in healthy eyes. Future studies are warranted to determine the exact mechanism(s) of this change.
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effect of pilocarpine hydrochloride on the Schlemm Canal in healthy eyes and eyes with open angle glaucoma
JAMA Ophthalmology, 2016Co-Authors: Rachel S Mogil, Alon Skaat, Jason L Chien, Sung-chul Park, Jeffrey M. Liebmann, Robert Ritch, Michael S RosmanAbstract:Importance The in vivo effect of pilocarpine hydrochloride on the Schlemm Canal may help explain its pharmacologic mechanism of action and better indicate its clinical use. Objective To investigate the effect of pilocarpine on the structure of the Schlemm Canal in vivo in healthy eyes and eyes with glaucoma. Design, Setting, and Participants In this case-control study, healthy individuals and patients with open-angle glaucoma were prospectively enrolled between September 1, 2013, and June 30, 2014, after a complete ophthalmologic examination at a tertiary glaucoma referral practice. Eighty-one serial, horizontal, enhanced depth imaging optical coherence tomographic B-scans (interval between B-scans, approximately 35 µm) of the nasal corneoscleral limbus were performed before and 1 hour after topical administration of pilocarpine, 1%, in 1 eye of healthy volunteers and pilocarpine, 2%, in 1 eye of patients with glaucoma. Fifty B-scans in the overlapping area (circumferential length, approximately 1.7 mm) between the 2 sets of serial scans (before and after pilocarpine administration) were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The cross-sectional area of the Schlemm Canal was measured in each selected B-scan. Volume of the Schlemm Canal was calculated using commercially available 3-dimensional reconstruction software. Main Outcomes and Measures Mean cross-sectional area of the Schlemm Canal. Results Enhanced depth imaging optical coherence tomographic scans of the Schlemm Canal were performed successfully before and after administration of pilocarpine, 1%, in 9 healthy eyes (9 individuals) and pilocarpine, 2%, in 10 eyes with glaucoma (10 patients) (mean [SD] age, 31.9 [7.8] and 68.7 [13.2] years, respectively). Following pilocarpine administration, mean (SD) intraocular pressure decreased from 14.3 (1.3) to 13.7 (1.1) mm Hg in healthy eyes ( P = .004) and from 17.5 (6.0) to 16.6 (6.1) mm Hg in eyes with glaucoma ( P = .01). The mean (SD) cross-sectional area of the Schlemm Canal increased by 21% (4667 [1704] to 5647 [1911] µm 2 ) in healthy eyes ( P 2 ) in eyes with glaucoma ( P 3 in healthy eyes ( P 3 in eyes with glaucoma ( P Conclusions and Relevance These data suggest that pilocarpine expands the Schlemm Canal in eyes with and without glaucoma. No differences in the effect were identified between the 2 groups. Enhanced depth imaging optical coherence tomography may be useful in investigating the effect of pharmacologic agents on the Schlemm Canal.
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effect of pilocarpine hydrochloride on the Schlemm Canal in healthy eyes and eyes with open angle glaucoma
JAMA Ophthalmology, 2016Co-Authors: Rachel S Mogil, Alon Skaat, Jason L Chien, Sung-chul Park, Jeffrey M. Liebmann, Robert Ritch, Michael S RosmanAbstract:Importance The in vivo effect of pilocarpine hydrochloride on the Schlemm Canal may help explain its pharmacologic mechanism of action and better indicate its clinical use. Objective To investigate the effect of pilocarpine on the structure of the Schlemm Canal in vivo in healthy eyes and eyes with glaucoma. Design, Setting, and Participants In this case-control study, healthy individuals and patients with open-angle glaucoma were prospectively enrolled between September 1, 2013, and June 30, 2014, after a complete ophthalmologic examination at a tertiary glaucoma referral practice. Eighty-one serial, horizontal, enhanced depth imaging optical coherence tomographic B-scans (interval between B-scans, approximately 35 µm) of the nasal corneoscleral limbus were performed before and 1 hour after topical administration of pilocarpine, 1%, in 1 eye of healthy volunteers and pilocarpine, 2%, in 1 eye of patients with glaucoma. Fifty B-scans in the overlapping area (circumferential length, approximately 1.7 mm) between the 2 sets of serial scans (before and after pilocarpine administration) were selected for analysis based on the structures of aqueous and blood vessels as landmarks. The cross-sectional area of the Schlemm Canal was measured in each selected B-scan. Volume of the Schlemm Canal was calculated using commercially available 3-dimensional reconstruction software. Main Outcomes and Measures Mean cross-sectional area of the Schlemm Canal. Results Enhanced depth imaging optical coherence tomographic scans of the Schlemm Canal were performed successfully before and after administration of pilocarpine, 1%, in 9 healthy eyes (9 individuals) and pilocarpine, 2%, in 10 eyes with glaucoma (10 patients) (mean [SD] age, 31.9 [7.8] and 68.7 [13.2] years, respectively). Following pilocarpine administration, mean (SD) intraocular pressure decreased from 14.3 (1.3) to 13.7 (1.1) mm Hg in healthy eyes ( P = .004) and from 17.5 (6.0) to 16.6 (6.1) mm Hg in eyes with glaucoma ( P = .01). The mean (SD) cross-sectional area of the Schlemm Canal increased by 21% (4667 [1704] to 5647 [1911] µm 2 ) in healthy eyes ( P 2 ) in eyes with glaucoma ( P 3 in healthy eyes ( P 3 in eyes with glaucoma ( P Conclusions and Relevance These data suggest that pilocarpine expands the Schlemm Canal in eyes with and without glaucoma. No differences in the effect were identified between the 2 groups. Enhanced depth imaging optical coherence tomography may be useful in investigating the effect of pharmacologic agents on the Schlemm Canal.
