AIM:To investigate the change of anterior chamber angle morphology and intraocular pressure(IOP) reduction after cataract surgery in patients with normal-tension glaucoma(NTG) using swept-source optical coherence tomo...AIM:To investigate the change of anterior chamber angle morphology and intraocular pressure(IOP) reduction after cataract surgery in patients with normal-tension glaucoma(NTG) using swept-source optical coherence tomography(SS-OCT).METHODS:This prospective,comparative,observational study recruited patients into two groups. Group 1 was the control group including normal subjects except those with cataracts(cataract group,n=67 eyes of 67 patients),and group 2 was NTG group including patients who were diagnosed with NTG and cataracts(n=43 eyes of 43 patients),which were treated with phacoemulsification and intraocular lens implantation. Before surgery,and at postoperative 1 and 6mo,anterior chamber angles were evaluated by SS-OCT under dark conditions using threedimensional angle analysis scan protocol. Angle opening distance(AOD),angle recess area(ARA),and trabeculariris surface area(TISA) at four quadrants(temporal,nasal,superior,and inferior) were calculated automatically by SS-OCT,after the observer marked scleral spurs.RESULTS: A total of 106 patients(54 males and 52 females) were enrolled in the study. Angle parameters,AOD,ARA,and TISA were increased after surgery in both groups. However,changes of angle parameters were only significant in group 2.In group 2,preoperative IOP was 13.2±2.9 mm Hg,and postoperative IOP at 1 and 6mo were 10.5±3.0 and 10.7±2.8 mm Hg,respectively. In group 1,preoperative IOP was 12.4±2.8 mm Hg,and postoperative IOP at 1 and 6mo were 11.6±2.5 and 12.0±2.8 mm Hg,respectively. After cataract surgery,angle parameters changed significantly while IOP significantly reduced and was maintained in group 2(P<0.001). The changes in angle parameters(ΔAOD500,ΔTISA500 at temporal; ΔAOD500,ΔARA500 at nasal) were linearly correlated with postoperative IOP changes.CONCLUSION: Cataract surgery may have improved anterior chamber angle parameters and decreased IOP in展开更多
The convergence confinement methods are solutions employed to estimate convergence in circular tunnels. They are mostly based on constitutive equations governed by the Mohr-Coulomb and Hoek-Brown yield criteria. Howev...The convergence confinement methods are solutions employed to estimate convergence in circular tunnels. They are mostly based on constitutive equations governed by the Mohr-Coulomb and Hoek-Brown yield criteria. However, the solutions based on these criteria neglect the intermediate principal stress confining effect on the ground reaction estimation. Therefore, in this paper, a Drucker-Prager yield criterion governed solution integrated with the Lode angle parameter is employed. It considers the intermediate principal stress influence and the critical effect of the parameter on failure characterization.Subsequently, it is verified with results attained from numerical simulations which consider an elasticperfectly plastic constitutive law with a non-associative flow rule within FLAC3D. It was drawn from the results that the ground reaction and plastic evolution are influenced by the confining stress.Furthermore, considering a suitable yield criterion leads to realistic convergence and plastic evolution estimation. The circumscribed DP criterion governed solution with Lode angle parameter value(0.8) is considered appropriate for the realistic ground reaction estimation in the three-dimensional(3D) stress state rock mass. It estimates approximately 3.4% of tunnel convergence as compared to the classic solutions(5%) and plastic radius estimated to be approximately 2.45 m compared to 2.84 m.展开更多
文摘AIM:To investigate the change of anterior chamber angle morphology and intraocular pressure(IOP) reduction after cataract surgery in patients with normal-tension glaucoma(NTG) using swept-source optical coherence tomography(SS-OCT).METHODS:This prospective,comparative,observational study recruited patients into two groups. Group 1 was the control group including normal subjects except those with cataracts(cataract group,n=67 eyes of 67 patients),and group 2 was NTG group including patients who were diagnosed with NTG and cataracts(n=43 eyes of 43 patients),which were treated with phacoemulsification and intraocular lens implantation. Before surgery,and at postoperative 1 and 6mo,anterior chamber angles were evaluated by SS-OCT under dark conditions using threedimensional angle analysis scan protocol. Angle opening distance(AOD),angle recess area(ARA),and trabeculariris surface area(TISA) at four quadrants(temporal,nasal,superior,and inferior) were calculated automatically by SS-OCT,after the observer marked scleral spurs.RESULTS: A total of 106 patients(54 males and 52 females) were enrolled in the study. Angle parameters,AOD,ARA,and TISA were increased after surgery in both groups. However,changes of angle parameters were only significant in group 2.In group 2,preoperative IOP was 13.2±2.9 mm Hg,and postoperative IOP at 1 and 6mo were 10.5±3.0 and 10.7±2.8 mm Hg,respectively. In group 1,preoperative IOP was 12.4±2.8 mm Hg,and postoperative IOP at 1 and 6mo were 11.6±2.5 and 12.0±2.8 mm Hg,respectively. After cataract surgery,angle parameters changed significantly while IOP significantly reduced and was maintained in group 2(P<0.001). The changes in angle parameters(ΔAOD500,ΔTISA500 at temporal; ΔAOD500,ΔARA500 at nasal) were linearly correlated with postoperative IOP changes.CONCLUSION: Cataract surgery may have improved anterior chamber angle parameters and decreased IOP in
基金The author gratefully acknowledges the financial support and affiliation from the University of Adelaide.
文摘The convergence confinement methods are solutions employed to estimate convergence in circular tunnels. They are mostly based on constitutive equations governed by the Mohr-Coulomb and Hoek-Brown yield criteria. However, the solutions based on these criteria neglect the intermediate principal stress confining effect on the ground reaction estimation. Therefore, in this paper, a Drucker-Prager yield criterion governed solution integrated with the Lode angle parameter is employed. It considers the intermediate principal stress influence and the critical effect of the parameter on failure characterization.Subsequently, it is verified with results attained from numerical simulations which consider an elasticperfectly plastic constitutive law with a non-associative flow rule within FLAC3D. It was drawn from the results that the ground reaction and plastic evolution are influenced by the confining stress.Furthermore, considering a suitable yield criterion leads to realistic convergence and plastic evolution estimation. The circumscribed DP criterion governed solution with Lode angle parameter value(0.8) is considered appropriate for the realistic ground reaction estimation in the three-dimensional(3D) stress state rock mass. It estimates approximately 3.4% of tunnel convergence as compared to the classic solutions(5%) and plastic radius estimated to be approximately 2.45 m compared to 2.84 m.
