Numerical Simulation of Iridectomy for Surgical Treatment of Glaucoma

Volume 4 ◽  
2004 ◽  
Author(s):  
Satish Kumar ◽  
Sumanta Acharya
Keyword(s):  
Three Dimensional ◽  
Elevated Pressure ◽  
Angle Closure Glaucoma ◽  
Angle Closure ◽  
Posterior Chamber ◽  
Three Dimensional Model ◽  
Pupillary Block ◽  
Flow Simulations ◽  
Outflow Pathway ◽  
Very High

Pupillary block can lead to a convex bowing of the iris surface due to the increased posterior chamber pressures, and this, in turn, can partially block the outflow pathway through the Trabecular Meshwork (TM). This condition leads to Angle-closure glaucoma by elevating the Intraocular Pressure (IOP) of the eye to very high levels. To alleviate this condition, a surgical process called iridectomy can be performed to create an opening on the iris surface that enables an alternate route for the flow from the posterior chamber to the anterior chamber. This, in turn, reduces the elevated pressure in the eye. In the present work, flow simulations are performed in a three-dimensional model of the human eye, with reduced irido-lenticular gap and partial-blockage of the TM, to model the flow and pressure distribution associated with pupillary block and angle-closure glaucoma. Iridectomy is simulated by creating holes on the iris surface at different locations. The effect of angular locations of the iridectomy holes on the pressure and flow distributions are analyzed.

scholarly journals Analysis of Cyclist’s Drag on the Aero Position Using Numerical Simulations and Analytical Procedures: A Case Study

2020 ◽  
Vol 17 (10) ◽  
pp. 3430 ◽  
Author(s):  
Pedro Forte ◽  
Daniel A. Marinho ◽  
Pantelis T. Nikolaidis ◽  
Beat Knechtle ◽  
Tiago M. Barbosa ◽  
...  
Keyword(s):  
Linear Regression ◽  
Numerical Simulations ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Paired Samples ◽  
Computational Fluid Dynamics Cfd ◽  
Analytical Procedures ◽  
Previous Training ◽  
Very High

Background: Resistance acting on a cyclist is a major concern among the cycling fraternity. Most of the testing methods require previous training or expensive equipment and time-consuming set-ups. By contrast, analytical procedures are more affordable and numerical simulations are perfect for manipulating and controlling inputs. The aim of this case study was to compare the drag of a cyclist in the aero position as measured using numerical simulation and analytical procedures. Methods: An elite male cyclist (65 kg in mass and 1.72 m in height) volunteered to take part in this research. The cyclist was wearing his competition gear, helmet and bicycle. A three-dimensional model of the bicycle and cyclist in the aero position was obtained to run the numerical simulations. Computational fluid dynamics (CFD) and a set of analytical procedures were carried out to assess drag, frontal area and drag coefficient, between 1 m/s and 22 m/s, with increments of 1 m/s. The t-test paired samples and linear regression were selected to compare, correlate and assess the methods agreement. Results: No significant differences (t = 2.826; p = 0.275) between CFD and analytical procedures were found. The linear regression showed a very high adjustment for drag (R2 = 0.995; p < 0.001). However, the drag values obtained by the analytical procedures seemed to be overestimated, even though without effect (d = 0.11). Conclusions: These findings suggest that drag might be assessed using both a set of analytical procedures and CFD.

Pseudophakic Pupillary Block With Angle-Closure Glaucoma in Diabetic Patients

1986 ◽  
Vol 102 (3) ◽  
pp. 325-328 ◽  
Author(s):  
Robert N. Weinreb ◽  
Jeffrey P. Wasserstrom ◽  
Jeffrey S. Forman ◽  
Robert Ritch
Keyword(s):  
Angle Closure Glaucoma ◽  
Angle Closure ◽  
Diabetic Patients ◽  
Pupillary Block

scholarly journals Outcomes of Small Size Ahmed Glaucoma Valve Implantation in Asian Chronic Angle-Closure Glaucoma

2021 ◽  
Vol 10 (4) ◽  
pp. 813
Author(s):  
Ke-Hao Huang ◽  
Ching-Long Chen ◽  
Da-Wen Lu ◽  
Jiann-Torng Chen ◽  
Yi-Hao Chen
Keyword(s):  
Visual Acuity ◽  
Intraocular Pressure ◽  
Anterior Chamber ◽  
Angle Closure Glaucoma ◽  
Adult Patients ◽  
Angle Closure ◽  
Posterior Chamber ◽  
Ahmed Glaucoma Valve ◽  
Probability Of Success ◽  
The Mean

For chronic angle-closure glaucoma (ACG), Ahmed glaucoma valve (AGV) is a useful drainage device for intraocular pressure (IOP) control but there are few reports discussing the outcomes of small size AGV in adult patients. This retrospective study involved 43 Asian adult patients (43 eyes) with chronic ACG. All patients had undergone small size AGV insertion and were divided into anterior chamber (AC) group and posterior chamber (PC) group. In the AC group, tube was inserted through sclerectomy gap into the anterior chamber. In the PC group, tube was inserted into posterior chamber through a needling tract. Outcome measures were intraocular pressure (IOP), visual acuity, number of antiglaucoma medications, survival curve and incidence of complications. In total, 43 eyes of 43 patients, 24 in the AC group and 19 in the PC group, were reviewed. The mean follow-up period was 28.5 months (95% confidence interval: 25.5–31.4). Mean IOP had significantly decreased following AGV insertion. The Kaplan–Meier survival analysis demonstrated a probability of success at 24 months of 67.4% for qualified success and 39.5% for complete success. There were no significant differences between the AC and PC groups in terms of the mean IOP, cumulative probability of success, visual acuity change or antiglaucoma medication change, except IOP at 1-day and 1-month mean IOP. The most common complications noted was hyphema in the PC group. For adult chronic ACG patients, small size AGV insertion could be effective at lowering IOP. Besides, tube insertion into AC with sclerectomy may prevent the hypertensive phase in the early postoperative period.

Does Spontaneous Blinking Increase Iris-Lens Contact?

2010 ◽  
Author(s):  
Rouzbeh Amini ◽  
Victor H. Barocas
Keyword(s):  
Aqueous Humor ◽  
Angle Closure Glaucoma ◽  
The Other ◽  
Abnormal Behavior ◽  
Angle Closure ◽  
Constant Flow ◽  
Primary Angle Closure ◽  
Primary Angle Closure Glaucoma ◽  
Outflow Pathway

The constant flow of aqueous humor (AH) in the anterior eye provides avascular tissues, notably the lens and cornea, with oxygen and nutrients (Fig. 1a). The hydrodynamics of AH and the iris contour are directly related to each other and abnormality of one may cause abnormal behavior in the other one. For example, in primary angle closure glaucoma, the abnormal anteriorly-located iris blocks the outflow pathway of AH. Increased AH pressure, in return, may push the iris more towards the anterior and worsen the blockage.

Late onset pupillary block glaucoma following phacoemulsification with posterior chamber intraocular lens implantation

2019 ◽  
Vol 30 (5) ◽  
pp. NP26-NP28
Author(s):  
Natasha Gautam Seth ◽  
Faisal Thattaruthody ◽  
Ajay Jurangal ◽  
Surinder Singh Pandav
Keyword(s):  
Intraocular Pressure ◽  
Intraocular Lens ◽  
Late Onset ◽  
Visual Outcome ◽  
Ultrasound Biomicroscopy ◽  
Angle Closure ◽  
Posterior Chamber ◽  
Pupillary Block ◽  
Flat Anterior Chamber ◽  
The Right

Secondary angle closure in a pseudophakic eye due to pupillary block, more than a decade following phacoemulsification, has not been reported. We managed a 75-year-old female presenting with sudden, painful diminution of vision and raised intraocular pressure in the right eye. The key finding was an almost flat anterior chamber with intraocular lens in normal position clinically as well as on ultrasound biomicroscopy. The posterior chamber was ballooned up by vitreous, which was cleared surgically to restore the anatomy. Meticulous clinical examination augmented by ultrasound biomicroscopy findings helped us to diagnose and manage this case for satisfactory intraocular pressure and visual outcome.

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