scholarly journals Development of an adjustable suture for trabeculectomy

2017 ◽  
Vol 3 (2) ◽  
pp. 55
Author(s):  
Yongjun Lai ◽  
Husam Elkaseh ◽  
Robert Campbell
Keyword(s):  
Intraocular Pressure ◽  
Postoperative Period ◽  
Ex Vivo ◽  
Common Operation ◽  
Ex Vivo Testing

This study reports a new suture design that enables simple, controlled intraocular pressure (IOP) adjustments in the postoperative period after trabeculectomy surgery, a common operation used in the treatment of glaucoma. Detailed configuration of this novel suture design and the process of fabricating the new sutures are demonstrated. Ex-vivo testing with prototyped sutures has demonstrated IOP drops of over 50% following suture adjustment. The concept of using adjustable suture to realize controllable IOP drop in the post trabeculectomy treatment is proved to be feasible.

About Puncture Testing Applied for Mechanical Characterization of Fetal Membranes

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Wilfried Bürzle ◽  
Edoardo Mazza ◽  
John J. Moore
Keyword(s):  
Deformation Behavior ◽  
Mechanical Characterization ◽  
Ex Vivo ◽  
Fetal Membrane ◽  
Membrane Rupture ◽  
Resistance To Deformation ◽  
Ex Vivo Testing ◽  
Insight Into

Puncture testing has been applied in several studies for the mechanical characterization of human fetal membrane (FM) tissue, and significant knowledge has been gained from these investigations. When comparing results of mechanical testing (puncture, inflation, and uniaxial tension), we have observed discrepancies in the rupture sequence of FM tissue and significant differences in the deformation behavior. This study was undertaken to clarify these discrepancies. Puncture experiments on FM samples were performed to reproduce previous findings, and numerical simulations were carried out to rationalize particular aspects of membrane failure. The results demonstrate that both rupture sequence and resistance to deformation depend on the samples' fixation. Soft fixation leads to slippage in the clamping, which reduces mechanical loading of the amnion layer and results in chorion rupturing first. Conversely, the stiffer, stronger, and less extensible amnion layer fails first if tight fixation is used. The results provide a novel insight into the interpretation of ex vivo testing as well as in vivo membrane rupture.

scholarly journals Lipofection of early passages of cell cultures derived from murine adenocarcinomas: In vitro and ex vivo testing of the thymidine kinase/ganciclovir system

2002 ◽  
Vol 9 (1) ◽  
pp. 96-99 ◽  
Author(s):  
Armando L Karara ◽  
Viviana F Bumaschny ◽  
Gabriel L Fiszman ◽  
Cecilia C Casais ◽  
Gerardo C Glikin ◽  
...  
Keyword(s):  
Thymidine Kinase ◽  
Cell Cultures ◽  
Ex Vivo ◽  
Ex Vivo Testing

scholarly journals Intraocular pressure elevation precedes a phagocytosis decline in a model of pigmentary glaucoma

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 174 ◽  
Author(s):  
Yalong Dang ◽  
Susannah Waxman ◽  
Chao Wang ◽  
Priyal Shah ◽  
Ralitsa T. Loewen ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Trabecular Meshwork ◽  
Ex Vivo ◽  
Pigment Dispersion ◽  
Pigmentary Glaucoma ◽  
Fluorescent Microspheres ◽  
Phagocytic Capacity ◽  
Pressure Transducers ◽  
Intraocular Pressure Elevation ◽  
Iop Elevation

Background: Outflow regulation and phagocytosis are key functions of the trabecular meshwork (TM), but it is not clear how the two are related in secondary open angle glaucomas characterized by an increased particle load. We hypothesized that diminished TM phagocytosis is not the primary cause of early ocular hypertension and recreated pigment dispersion in a porcine ex vivo model. Methods: Sixteen porcine anterior chamber cultures received a continuous infusion of pigment granules (Pg), while 16 additional anterior chambers served as controls (C). Pressure transducers recorded the intraocular pressure (IOP). The phagocytic capacity of the trabecular meshwork was determined by fluorescent microspheres. Results: The baseline IOPs in Pg and C were similar (P=0.82). A significant IOP elevation occurred in Pg at 48, 120, and 180 hours (all P<0.01, compared to baseline). The pigment did not cause a reduction in TM phagocytosis at 48 hours, when the earliest IOP elevation occurred, but at 120 hours onward (P=0.001 compared to C). This reduction did not result in an additional IOP increase at 120 or 180 hours compared to the first IOP elevation at 48 hours (P>0.05). Conclusions: In this porcine model of pigmentary glaucoma, an IOP elevation occurs much earlier than when phagocytosis fails, suggesting that two separate mechanisms might be at work.

Intraocular Pressure Estimation Method Based on Vibration Propagation Characteristics According to Structure Contact

2021 ◽  
Vol 263 (1) ◽  
pp. 5552-5554
Author(s):  
Kim Deukha ◽  
Seongwook Jeon ◽  
Won June Lee ◽  
Junhong Park
Keyword(s):  
Intraocular Pressure ◽  
Short Term Memory ◽  
Learning Algorithm ◽  
Ex Vivo ◽  
Estimation Method ◽  
Biological Tissues ◽  
Response To Treatment ◽  
Deep Learning Algorithm ◽  
Cross Correlation Analysis ◽  
Porcine Eyes

Intraocular pressure (IOP) measurement is one of the basic tests performed in ophthalmology and is known to be an important risk factor for the development and progression of glaucoma. Measurement of IOP is important for assessing response to treatment and monitoring the progression of the disease in glaucoma. In this study, we investigate a method for measuring IOP using the characteristics of vibration propagation generated when the structure is in contact with the eyeball. The response was measured using an accelerometer and a force sensitive resistor to determine the correlation between the IOP. Experiment was performed using ex-vivo porcine eyes. To control the IOP, a needle of the infusion line connected with the water bottle was inserted into the porcine eyes through the limbus. A cross correlation analysis between the accelerometer and the force sensitive resistor was performed to derive a vibration factor that indicate the change in IOP. In order to analyze the degree of influence of biological tissues such as the eyelid, silicon was placed between the structure and the eyeball. The Long Short-Term Memory (LSTM) deep learning algorithm was used to predict IOP based on the vibration factor.

Intraocular Pressure Fluctuations During Strabismus Operations and the Postoperative Period

1999 ◽  
Vol 30 (3) ◽  
pp. 212-215 ◽  
Author(s):  
Moshe Snir ◽  
Ruth Axer-Siegel ◽  
J Chalimi ◽  
B Shalev ◽  
Yuval Yassur
Keyword(s):  
Intraocular Pressure ◽  
Postoperative Period ◽  
Pressure Fluctuations

scholarly journals Design of a Multifunctional Forceps for Use in Endoscopic Surgery

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Andrew Rau ◽  
Mary Frecker ◽  
Abraham Mathew ◽  
Eric Pauli
Keyword(s):  
Minimally Invasive ◽  
Endoscopic Surgery ◽  
Minimally Invasive Surgical Procedures ◽  
Ex Vivo ◽  
Catastrophic Failure ◽  
Minimally Invasive Surgical ◽  
Design Characteristics ◽  
Fail Safe ◽  
Ex Vivo Testing ◽  
Good Agreement

This paper presents a 3.0 mm diameter endoscopic forceps design for use in minimally invasive surgical procedures, which require significant grasping and spreading forces. Models of the proposed design predict considerable improvements in the opening range (140%) and force application (87%) for both grasping and spreading when compared with currently used endoscopic forceps. Several of the tool’s design characteristics promote fail-safe malfunctions, including locking before catastrophic failure and the decreased likelihood in detached parts. Initial benchtop testing showed good agreement between prototype performance and model prediction. Frictional losses experienced during testing were found to depend on load orientation. A surgical prototype is currently being manufactured for ex vivo testing.

scholarly journals Intraocular Pressure Study in Ex Vivo Pig Eyes by the Laser-Induced Cavitation Technique: Toward a Non-Contact Intraocular Pressure Sensor

2020 ◽  
Vol 10 (7) ◽  
pp. 2281
Author(s):  
Santiago Camacho-Lopez ◽  
Carlos Andrés Zuñiga-Romero ◽  
Luis Felipe Devia-Cruz ◽  
Carolina Alvarez-Delgado ◽  
Marcos Antonio Plata-Sanchez ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Cavitation Bubble ◽  
Bubble Dynamics ◽  
Continuous Wave ◽  
Ex Vivo ◽  
Applanation Tonometry ◽  
Reliable Technique ◽  
Measurement Resolution ◽  
In Vivo Diagnosis

Traditional applanation tonometry techniques lack the necessary accuracy and reliability for measuring the intraocular pressure (IOP), and there is still a need for a reliable technique for in vivo diagnosis. A single laser-induced cavitation bubble event was optically monitored in order to precisely measure the first collapse time of the cavitation bubble, which presents a direct dependence on the liquid pressure. This can certainly be done within the IOP range. We now extend the partial transmittance modulation (STM) technique to determine its feasibility for directly measuring the IOP by studying the nanosecond (ns) pulsed laser-induced cavitation bubble dynamics for an externally pressurized fresh ex vivo porcine eye. The results demonstrate that it is possible to monitor the IOP by detecting the light of a continuous-wave (CW) laser beam which is intensity modulated by the bubble itself. This technique currently presents a measurement resolution of about 4 mmHg in the 5 to 50 mmHg pressure range, indicating the feasibility of this approach for measuring IOP. This technique provides a direct measurement within the anterior eye chamber, avoiding common pitfalls in IOP diagnosis, such as errors due to patient movement, varying physical properties of the eye globe, or central cornea thickness (CCT) effects.

scholarly journals Formulation and Characterization of Carvedilol Leciplex for Glaucoma Treatment: In-Vitro, Ex-Vivo and In-Vivo Study

Pharmaceutics ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 197 ◽  
Author(s):  
Doaa Hassan ◽  
Rehab Abdelmonem ◽  
Menna Abdellatif
Keyword(s):  
Particle Size ◽  
Intraocular Pressure ◽  
Zeta Potential ◽  
Ex Vivo ◽  
Entrapment Efficiency ◽  
Molar Ratio ◽  
Duration Of Action ◽  
Corneal Permeability ◽  
Glaucoma Treatment

This study evaluated the efficacy of cationic nanoparticle (leciplex) to deliver carvedilol to ocular surface for glaucoma treatment as recent studies pointed out the effect of topical carvedilol on intraocular pressure, therefore carvedilol loaded leciplex formulae were prepared using soy phosphatidyl choline (SPC) and cationic surfactant (CTAB/DDAB) and characterized for morphology, entrapment efficiency, particle size, zeta potential and ex-vivo corneal permeation. Then the selected formula was evaluated via in-vivo studies in comparison with carvedilol solution. Leciplex nanoparticles appeared spherical in shape with entrapment efficiency exceeded 95% in all formulae. Leciplex formula composed of SPC and DDAB in (1:1) molar ratio showed the smallest particle size (16.04 ± 1.2 nm), highest zeta potential value (53.9 ± 0.91 mv) and highest apparent corneal permeability coefficient (0.1157 cm/h). Carvedilol leciplex reduced intraocular pressure (IOP) to normal range in ocular hypertensive rabbits after 30 min and duration of action lasted for 24 h, while carvedilol solution reduced IOP to normal value after 60 min and duration of action lasted for 6 h. Furthermore, histological examination of eyeballs of rabbits treated with carvedilol leciplex showed improvement of retinal atrophy of glaucomatous eyes. This study concluded that leciplex improve transcorneal permeation and bioavailability of carvedilol.

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