Effects of Biological Stimuli on the Viscosity of the Vitreous

Honda, Yoshio; Negi, Akira

doi:10.1111/j.1755-3768.1982.tb00630.x

Cited by 21 publications

(13 citation statements)

References 12 publications

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“…13 Cold storage of eyes, however, has shown to reduce degradation of vitreous viscosity and colder temperatures are known to increase vitreous viscosity. 13,14 Although eyes were allowed to equilibrate to room temperature in our study, eyes were not warmed to physiologic temperature and vitreous temperature was not measured. Thus, the effect of vitreous temperature on reflux after intraocular injection was not measured and could be future areas of investigation.…”

Section: Discussionmentioning

confidence: 99%

Volume and Composition of Reflux After Intravitreal Injection

Brodie

Ruggiero

Ghodasra

et al. 2014

Retina

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Purpose To quantify the amount of drug loss from cadaveric human eyes which are injected via the pars plana with a known volume of dye at variable intraocular pressures. Methods Eight cadaver eyes were divided into two intraocular pressure groups: normal (15 mmHg, 4 eyes) or high (30 mmHg, 4 eyes). Each eye was injected with 50 µl of hematoxylin dye and the subsequent reflux was immediately collected on a Schirmers test strip. The test strip was scanned and digitally analyzed to determine the area of saturation and total color intensity present. Using a previously established equation, total volume of reflux and amount of dye within that reflux were calculated. Results The average total volume of refluxed fluid was 1.68 µL (median: 0.62 µL), with a range of 0 µL to 8.05 µL. The average volume of refluxed dye was 0.37 µL (median: 0.08 µL), with a range of 0 µL to 2.15 µL. On average only 0.74% of the original 50 µL of injected dye was lost (median: 0.15%), with a range from 0% to 4.30%. Conclusion Although the presence of subconjunctival bleb formation after intravitreal injection may be concerning to the clinician, our data shows that only a very small amount of the injected therapeutic agent is lost in the reflux.

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Section: Discussionmentioning

confidence: 99%

Volume and Composition of Reflux After Intravitreal Injection

Brodie

Ruggiero

Ghodasra

et al. 2014

Retina

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“…The human vitreous is a non-homogeneous structure, which given its small volume makes traditional measurement of its viscosity, elasticity, plasticity and thixotropy technically challenging [14]. Thus, alternative methods of measuring vitreous biomechanical properties of cadaver eyes have been developed, using dynamic light scattering [10], NMR imaging [15] or core vitrectomy and measurement of wet weight reduction of eyes [9].…”

Section: Discussionmentioning

confidence: 99%

Effect of intravitreal plasmin on vitreous removal through a 25-gauge cutting system in the rabbit in vivo

Hermel

Prenner

Alabdulrazzak

et al. 2008

Graefes Arch Clin Exp Ophthalmol

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“…Even after age‐related vitreous liquefaction, collagen structures, eventually collapsed, are still present inside the eye globe, and can affect the vitreous rheology. Moreover, the variety of methodologies, shear frequencies and viscosity definitions used in the literature , combined with the frequency dependence and bimodality of the vitreous viscoelasticity, make a meaningful comparison difficult. Nevertheless, the value found for the storage and loss components of the viscoelastic modulus G at the relatively low eye movement frequency used are around 3 ± 1 hPa, which is one order of magnitude higher than the values obtained from the high‐frequency ex vivo measurement made after degradation of the intravitreal membranes .…”

Section: Discussionmentioning

confidence: 99%

Vitreous deformation during eye movement

et al. 2011

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Retinal detachment results in visual loss and requires surgical treatment. The risk of retinal detachment depends, among other factors, on the vitreous rheology, which varies with age. To date, the viscoelasticity of the vitreous body has only been measured in cadaver eyes. However, the ex vivo and in vivo viscoelasticity may differ as a result of the effect of intravitreal membranes. Therefore, an MRI method and appropriate postprocessing tools were developed to determine the vitreous deformation and viscoelastic properties in the eyes of living humans. Nineteen subjects (eight women and 11 men; mean age, 33 years; age range, 14-62 years) gazed at a horizontal sinusoidal moving target during the segmented acquisition of complementary spatial modulation of magnetization images. The center of the lens and the scleral insertion of the optic nerve defined the imaging plane. The vitreous deformation was tracked with a dedicated algorithm and fitted with the commonly used viscoelastic model to determine the model parameters: the modified Womersley number a and the phase angle b. The vitreous deformation was successfully quantified in all 17 volunteers having a monophasic vitreous. The mean and standard deviation of the model parameters were determined to be 5.5 ± 1.3 for a and -2.3 ± 0.2 for b. The correlation coefficient (-0.76) between a and b was significant. At the eye movement frequency used, the mean storage and loss moduli of the vitreous were around 3 ± 1 hPa. For two subjects, the vitreous deformation was clearly polyphasic: some compartments of the vitreous were gel-like and others were liquefied. The borders of these compartments corresponded to reported intravitreal membrane patterns. Thus, the deformation of the vitreous can now be determined in situ, leaving the structure of the intravitreal membranes intact. Their effect on vitreous dynamics challenges actual vitreous viscoelastic models. The determination of the vitreous deformation will aid in the quantification of local vitreous stresses and their correlation with retinal detachment. Give the full address, including e-mail, telephone and fax, of the author who is to check the proofs. Vitreous deformation during eye movement was depicted using tagging and tracked with a dedicated algorithm. Inhomogeneous deformations' pattern and viscoelastic properties could be revealed inside the vitreous . The viscosity and elasticity of the vitreous was quantified in-vivo from its deformation with an analytical model, and the results are depicted here as a function of subject age. Vitreous Deformation during Eye Movement AbstractRetinal detachment results in visual loss and requires surgical treatment. The risk of retinal detachment depends, among other factors, upon the vitreous rheology, which varies with age. Up to now, the viscoelasticity of the vitreous body has only been measured in cadaver eyes. However, the ex-vivo and in-vivo viscoelasticity may differ, due to the effect of intravitreal membranes. Therefore, a MRI method and appropriate postp...

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Effects of Biological Stimuli on the Viscosity of the Vitreous

Cited by 21 publications

References 12 publications

Volume and Composition of Reflux After Intravitreal Injection

Volume and Composition of Reflux After Intravitreal Injection

Effect of intravitreal plasmin on vitreous removal through a 25-gauge cutting system in the rabbit in vivo

Vitreous deformation during eye movement

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