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.

scholarly journals Ex vivo and in vivo study of Kowa HA-2 applanation tonometer in the measurement of intraocular pressure in cats

2017 ◽  
Vol 38 (6) ◽  
pp. 3647
Author(s):  
Claudia Lizandra Ricci ◽  
Rogério Giuffrida ◽  
Glaucia Prada Kanashiro ◽  
Hilidia Stephania Rufino Belezzi ◽  
Carolina De Carvalho Bacarin ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Ex Vivo ◽  
Clinical Signs ◽  
In Vivo Study ◽  
Eye Drops ◽  
Significant Difference ◽  
Applanation Tonometer ◽  
Ex Vivo Study ◽  
Healthy Eyes

The objective of this study was to evaluate the use of the Kowa HA-2 applanation tonometer in measuring intraocular pressure (IOP) in cats. Ten healthy eyes were used in an ex vivo study in which the calibration curve for manometry vs. tonometry was determined by artificially raising the IOP in 5 mmHg increments up to 60 mmHg (10-60 mmHg). Both eyes of 10 anesthetized cats were studiedin vivo to compare manometry vs. tonometry. In the ambulatory study, 78 healthy eyes, 7 eyes with glaucoma and 20 eyes with uveitis were evaluated by tonometry, which was performed with topical anesthesia and 1% fluorescein eye drops for the formation of fluorescein semicircles. The correlation coefficient (r²) between the manometer and the Kowa HA-2 tonometer was 0.993 and the linear regression equation was y = 0.0915x + 0.0878 in the ex-vivo study. In the in vivo study, the IOP values (mean±SD, in mmHg) in manometry were 15.6 ± 1.1(14.0 – 17.5) and in tonometry were 15.5 ± 1.2(13.5 – 17.2), with no significant difference (P > 0.05) between manometry and tonometry. In ambulatory study, using the Kowa HA-2 tonometer, the IOP values (mean±SD, in mmHg) were 15.0 ± 1.5 (11.8 – 18.3) for the healthy eyes, 38.4 ± 8.1(29.6 – 53.7) for glaucomatous eyes and 10.4 ± 2.0(5.3 – 12.2) for eyes with uveitis. There was a strong correlation and accuracy between the IOP values with the manometry and the Kowa HA-2 tonometer. In the ambulatorystudy the IOP values obtained with the tonometer were compatible for animals with healthy eyes and with clinical signs of glaucoma and uveitis. We conclude that the Kowa HA-2 tonometer can be used in the measurement of IOP in cats, since it is a practical and accurate method in this species.

Fiber Optic Microneedles for Transdermal Light Delivery: Ex Vivo Porcine Skin Penetration Experiments

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Mehmet A. Kosoglu ◽  
Robert L. Hood ◽  
Ye Chen ◽  
Yong Xu ◽  
Marissa Nichole Rylander ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Fiber Optic ◽  
Ex Vivo ◽  
Skin Penetration ◽  
Average Diameter ◽  
Drawing Process ◽  
Pig Skin ◽  
In Vivo Diagnosis ◽  
Skin Samples

Shallow light penetration in tissue has been a technical barrier to the development of light-based methods for in vivo diagnosis and treatment of epithelial carcinomas. This problem can potentially be solved by utilizing minimally invasive probes to deliver light directly to target areas. To develop this solution, fiber optic microneedles capable of delivering light for either imaging or therapy were manufactured by tapering step-index silica-based optical fibers employing a melt-drawing process. Some of the microneedles were manufactured to have sharper tips by changing the heat source during the melt-drawing process. All of the microneedles were individually inserted into ex vivo pig skin samples to demonstrate the feasibility of their application in human tissues. The force on each microneedle was measured during insertion in order to determine the effects of sharper tips on the peak force and the steadiness of the increase in force. Skin penetration experiments showed that sharp fiber optic microneedles that are 3 mm long penetrate through 2 mm of ex vivo pig skin specimens. These sharp microneedles had a minimum average diameter of 73 μm and a maximum tip diameter of 8 μm. Flat microneedles, which had larger tip diameters, required a minimum average diameter of 125 μm in order to penetrate through pig skin samples. Force versus displacement plots showed that a sharp tip on a fiber optic microneedle decreased the skin’s resistance during insertion. Also, the force acting on a sharp microneedle increased more steadily compared with a microneedle with a flat tip. However, many of the sharp microneedles sustained damage during skin penetration. Two designs that did not accrue damage were identified and will provide a basis of more robust microneedles. Developing resilient microneedles with smaller diameters will lead to transformative, novel modes of transdermal imaging and treatment that are less invasive and less painful for the patient.

scholarly journals Ex vivo and in vivo study of Kowa HA-2 applanation tonometer in the measurement of intraocular pressure in dogs

2016 ◽  
Vol 37 (2) ◽  
pp. 797
Author(s):  
Silvia Franco Andrade ◽  
Alexandre Lima de Andrade ◽  
Glaucia Prada Kanashiro ◽  
Danielle Alves Silva ◽  
Rafael Cabral Barbero ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Ex Vivo ◽  
In Vivo Study ◽  
Eye Drops ◽  
Significant Difference ◽  
Applanation Tonometer ◽  
Anesthetized Dogs ◽  
Ex Vivo Study ◽  
Healthy Eyes

The objective of this study was to evaluate the use of the Kowa HA-2 applanation tonometer in measuring intraocular pressure (IOP) in dogs. Twenty eyes were used in an ex vivo study in which the calibration curve for manometry vs. tonometry was determined by artificially raising the IOP in 5 mmHg increments up to 60 mmHg (10-60 mmHg). Both eyes of 10 anesthetized dogs were studied in vivo to compare manometry vs. tonometry. In the ambulatory study, 168 healthy eyes, 74 eyes with glaucoma and 60 eyes with uveitis were evaluated by tonometry, which was performed with topical anesthesia and 1% fluorescein eye drops for the formation of fluorescein semicircles. The ex vivo study showed an excellent correlation coefficient (r2= 0.993) between the aneroid manometer and the Kowa HA-2 tonometer. In the in vivo study, there was no significant difference (P>0.05) between the IOP values by manometry and tonometry, showing the excellent accuracy of the Kowa HA-2 tonometer. In the ambulatory study using the Kowa HA-2 tonometer, the IOP values (mean±SD, in mmHg) were 15.1±1.8 (12.0 – 20.0) for the healthy eyes, 25.2±4.0 (20.0 – 38.0) for glaucomatous eyes and 10.1±2.3 (5.0 – 13.7) for eyes with uveitis. There was a strong correlation between the IOP values obtained by direct ocular manometry and those from the Kowa HA-2 tonometer. In the ambulatory study, the IOP values measured by the tonometer were compatible for healthy eyes and for eyes with glaucoma or uveitis. We conclude that Kowa HA-2 applanation tonometer is accurate and practical for IOP measurement in dogs.

scholarly journals Characterization and Ex Vivo Application of Indocyanine Green Chitosan Patches in Dura Mater Laser Bonding

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2130
Author(s):  
Francesca Rossi ◽  
Giada Magni ◽  
Roberto Colasanti ◽  
Martina Banchelli ◽  
Maurizio Iacoangeli ◽  
...  
Keyword(s):  
Indocyanine Green ◽  
Dura Mater ◽  
Continuous Wave ◽  
Ex Vivo ◽  
Aluminium Gallium Arsenide ◽  
In Vivo Models ◽  
Bonding Effect ◽  
Pressure Tests ◽  
Laser Bonding

Dura mater repair represents a final and crucial step in neurosurgery: an inadequate dural reconstruction determines dreadful consequences that significantly increase morbidity and mortality rates. Different dural substitutes have been used with suboptimal results. To overcome this issue, in previous studies, we proposed a laser-based approach to the bonding of porcine dura mater, evidencing the feasibility of the laser-assisted procedure. In this work, we present the optimization of this approach in ex vivo experiments performed on porcine dura mater. An 810-nm continuous-wave AlGaAs (Aluminium Gallium Arsenide) diode laser was used for welding Indocyanine Green-loaded patches (ICG patches) to the dura. The ICG-loaded patches were fabricated using chitosan, a resistant, pliable and stable in the physiological environment biopolymer; moreover, their absorption peak was very close to the laser emission wavelength. Histology, thermal imaging and leak pressure tests were used to evaluate the bonding effect. We demonstrated that the application of 3 watts (W), pulsed mode (Ton 30 ms, Toff 3.5 ms) laser light induces optimal welding of the ICG patch to the dura mater, ensuring an average fluid leakage pressure of 216 ± 105 mmHg, falling within the range of physiological parameters. This study demonstrated that the thermal effect is limited and spatially confined and that the laser bonding procedure can be used to close the dura mater. Our results showed the effectiveness of this approach and encourage further experiments in in vivo models.

Dynamic Contour Tonometry and Goldmann Applanation Tonometry: Correlation with Intracameral Assessment of Intraocular Pressure

2011 ◽  
Vol 22 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Ivano Riva ◽  
Luciano Quaranta ◽  
Andrea Russo ◽  
Andreas Katsanos ◽  
Eliana Rulli ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Anterior Chamber ◽  
Open Angle Glaucoma ◽  
Corneal Thickness ◽  
Applanation Tonometry ◽  
Dynamic Contour Tonometry ◽  
Altman Plot ◽  
Applanation Tonometer ◽  
The Relationship

Purpose To compare intraocular pressure (IOP) measured using a dynamic contour tonometer (DCT) and a Goldmann applanation tonometer (GAT) with in vivo intracameral IOP, and establish the relationship between DCT, GAT and central corneal thickness (CCT) in patients with primary open-angle glaucoma (POAG). Materials and Methods We examined 50 eyes of 50 patients with POAG scheduled for glaucoma or cataract surgery. Immediately before surgery, CCT, GAT and DCT IOP were assessed, after which manometry of the anterior chamber was performed. A Bland-Altman plot was used to test the agreement among the 3 measurements of IOP, and univariate and multivariate regression analyses were used to evaluate the effect of CCT on DCT and GAT. Results On average, the DCT readings were 4.0±1.6 mmHg higher than the GAT readings and 2.3±2.4 mmHg higher than the manometric readings; the GAT measurements were generally a mean 1.7±1.8 mmHg lower than the manometric readings. The CCT had an almost similar influence on DCT and GAT measurements (p=0.84). Conclusions The DCT-measured IOP was significantly higher than that measured by means of GAT and anterior chamber manometry. The DCT and GAT readings were both influenced by CCT to the same extent.

Ex vivo and in vivo diagnosis of C6 glioblastoma development by Raman spectroscopy coupled to a microprobe

2010 ◽  
Vol 398 (1) ◽  
pp. 477-487 ◽  
Author(s):  
Abdelilah Beljebbar ◽  
Sylvain Dukic ◽  
Nadia Amharref ◽  
Michel Manfait
Keyword(s):  
Raman Spectroscopy ◽  
Ex Vivo ◽  
In Vivo Diagnosis
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