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Acta Ophthalmologica Aug 2008Vitreomacular traction resulting from lacking, incomplete or anomalous posterior vitreous detachment is suspected to play a crucial role in the pathogenesis of different... (Review)
Review
Vitreomacular traction resulting from lacking, incomplete or anomalous posterior vitreous detachment is suspected to play a crucial role in the pathogenesis of different forms of age-related macular degeneration (AMD) along with the known mechanisms. It is probable that the fundamental pathomechanisms of AMD formation have already begun by the time tractional forces lead to a change for the worse. Vitreomacular traction alone is perhaps not able to induce AMD. It would seem sensible to consider vitreous changes when diagnosing and treating AMD patients because of the high coincidence of vitreomacular traction and choroidal neovascularization (CNV) and the often successful treatment of other diseases of the vitreoretinal interface by vitrectomy. The concept of the pathogenesis of AMD should therefore be extended to include the influence of the vitreous, especially where therapeutic concepts such as pharmacological vitreolysis and vitreous separation have been established as causative treatment of late forms of AMD.
Topics: Adhesiveness; Exudates and Transudates; Humans; Macular Degeneration; Retina; Tissue Adhesions; Vitreous Body
PubMed: 18537930
DOI: 10.1111/j.1755-3768.2008.01210.x -
BMC Veterinary Research Oct 2014Sonographic ophthalmic examinations have become increasingly important in veterinary medicine. If the velocity of ultrasound in ocular tissues is known, the A-mode...
BACKGROUND
Sonographic ophthalmic examinations have become increasingly important in veterinary medicine. If the velocity of ultrasound in ocular tissues is known, the A-mode ultrasound method may be used to determine the axial intraocular distances, such as anterior chamber depth, lens thickness, axial length of the vitreous and axial globe length, which are required for intraocular lens (IOL) power calculations. To the authors' knowledge, the velocity of ultrasound in the ocular tissues of the horse was not previously determined. In the present study, 33 lenses, 29 samples of aqueous and 31 of vitreous from 35 healthy equine eyes have been examined. The corresponding ultrasound velocities are reported in dependence of age, temperature, gender and elapsed time after enucleation.
RESULTS
The velocity of ultrasound at 36°C in equine aqueous, lens and vitreous are 1529 ±10 m/s, 1654± 29 m/s and 1527 ±16 m/s respectively, and the corresponding conversion factors are 0.998± 0.007, 1.008 ±0.018 and 0.997 ±0.010. A linear increase of the speed of ultrasound with increasing temperature has been determined for aqueous and vitreous. No temperature dependence was found for the speed of ultrasound in the lens. The ultrasound velocity did not significantly differ (95%) on the basis of gender, age or time after enucleation during the first 72 hours after death.
CONCLUSIONS
Compared to human eyes, the ultrasound velocity in equine lental tissue deviates by one percent. Therefore, axial length measurements obtained with ultrasound velocities for the human eye must be corrected using conversion factors. For the aqueous and vitreous, deviations are below one percent and can be neglected in clinical settings.
Topics: Animals; Aqueous Humor; Female; Horses; Lens, Crystalline; Male; Ultrasonography; Vitreous Body
PubMed: 25312851
DOI: 10.1186/s12917-014-0250-3 -
Indian Journal of Ophthalmology Apr 2022Diabetic membranes are always a challenge for a surgeon because of sticky nature and chances of iatrogenic break while removing.
BACKGROUND
Diabetic membranes are always a challenge for a surgeon because of sticky nature and chances of iatrogenic break while removing.
PURPOSE
To demonstrate a safe reverse swiss roll technique to dissect diabetic vitreous membranes.
SYNPOSIS
Approaches and techniques for membrane dissection are segmentation, delamination and en-bloc dissection using various types of instruments and illumination. With vitreous cutte, picks and scissors, surgical steps are traditionallu performed by using classic lift and shave technique. After identifying the plane, tissue is lifted and then cut, which puts the retina at risk of break because of traction and active suction. Such a threat can be reduced by placing the cutter above the membrane thereby having the membrane itseld acting as a protective cushion to the retina. Port here, unlike lift and shave technique, doesn't face the edge of membrane but is exactly 180 degree opposite and membrane curls into port because of suction. Also, hemostasis is maintained by continuous aspiration and cutting as the instrument is moved side to side, retracting from the edge.
HIGHLIGHTS
Reverse swiss roll technique is safer compared to lift and shave because of the safety cushion of the membrane between the port and the retina. There is inherently less chances of retinal break because the active suction from the port is directed away from the retina. The technique also minimises traction and localised pull on the atrophic macula.
VIDEO LINK
https://youtu.be/WNnSsP69ZLw.
Topics: Diabetes Mellitus; Humans; Retinal Perforations; Switzerland; Vitrectomy; Vitreous Body
PubMed: 35326086
DOI: 10.4103/ijo.IJO_631_22 -
BMJ Case Reports Jan 2017
Topics: Adult; Athletic Injuries; Eye Injuries; Humans; Male; Vitreous Body; Vitreous Hemorrhage; Wounds, Nonpenetrating
PubMed: 28052952
DOI: 10.1136/bcr-2016-218303 -
Investigative Ophthalmology & Visual... Mar 2023Age-related macular degeneration (AMD) is the leading cause of visual impairment worldwide. In this study, we aimed to investigate the vitreous humor metabolite profiles...
PURPOSE
Age-related macular degeneration (AMD) is the leading cause of visual impairment worldwide. In this study, we aimed to investigate the vitreous humor metabolite profiles of patients with intermediate AMD using untargeted metabolomics.
METHODS
We performed metabolomics using high-resolution liquid chromatography mass spectrometry on the vitreous humor of 31 patients with intermediate AMD and 30 controls who underwent vitrectomy for epiretinal membrane with or without cataract surgery. Univariate analyses after false discovery rate correction were performed to discriminate the metabolites and identify the significant metabolites of intermediate AMD. For biologic interpretation, enrichment and pathway analysis were conducted using MetaboAnalyst 5.0.
RESULTS
Of the 858 metabolites analyzed in the vitreous humor, 258 metabolites that distinguished patients with AMD from controls were identified (P values < 0.05). Ascorbic acid and uric acid levels increased in the AMD group (all P values < 0.05). The acyl carnitines, such as acetyl L-carnitine (1.37-fold), and fatty amides, such as anandamide (0.9-fold) and docosanamide (0.67-fold), were higher in patients with intermediate AMD. In contrast, nicotinamide (-0.55-fold), and succinic acid (-1.69-fold) were lower in patients with intermediate AMD. The metabolic pathway related oxidation of branched chain fatty acids and carnitine synthesis showed enrichment.
CONCLUSIONS
Multiple metabolites related to fatty amides and acyl carnitine were found to be increased in the vitreous humor of patients with intermediate AMD, whereas succinic acid and nicotinamide were reduced, suggesting that altered metabolites related to fatty amides and acyl carnitines and energy metabolism may be implicated in the etiology of AMD.
Topics: Humans; Amides; Carnitine; Macular Degeneration; Niacinamide; Succinates; Vitreous Body
PubMed: 36939720
DOI: 10.1167/iovs.64.3.28 -
Journal of Biomedical Optics 2004Imaging the vitreous is an attempt to view what is by design invisible. The inability to adequately image vitreous hinders a more complete understanding of its normal... (Review)
Review
Imaging the vitreous is an attempt to view what is by design invisible. The inability to adequately image vitreous hinders a more complete understanding of its normal structure and function and how these change in aging and disease. The combined use of more than one technique could provide better imaging for investigational and clinical purposes. Past and present imaging methodologies are summarized and research and clinical techniques that are currently in development for future applications, are discussed. Dark-field slit microscopy has been used to characterize vitreous anatomy, both within the vitreous body as well as at the vitreo-retinal interface. In addition to this methodology, slit-lamp biomicroscopy; direct, indirect, and scanning laser ophthalmoscopies; ultrasonography; optical coherence tomography; magnetic resonance and Raman spectroscopies; and dynamic light-scattering methodologies for noninvasive evaluation are presented. Dark-field slit microscopy enables in vitro imaging without dehydration or tissue fixatives. Optical coherence tomography enables better in vivo visualization of the vitreo-retinal interface than scanning laser ophthalmoscopy and ultrasonography, but does not image the vitreous body. Dynamic light scattering can determine the average sizes of vitreous macromolecules within the vitreous body as well as possibly image the posterior vitreous cortex once detached, while Raman spectroscopy can detect altered vitreous molecules, such as glycated collagen and other proteins in diabetic vitreopathy.
Topics: Eye Diseases; Humans; Ophthalmoscopes; Ophthalmoscopy; Photometry; Scattering, Radiation; Spectrum Analysis; Tomography, Optical Coherence; Ultrasonography; Vitreous Body
PubMed: 14715056
DOI: 10.1117/1.1627339 -
Asia-Pacific Journal of Ophthalmology... 2020Vitreous floaters are a common cause for presentation to ophthalmologists, and may significantly affect visual function. In the absence of some more serious underlying... (Review)
Review
Vitreous floaters are a common cause for presentation to ophthalmologists, and may significantly affect visual function. In the absence of some more serious underlying pathology such as uveitis, many patients may not experience significant persistent visual impairment from floaters. For some patients, the symptomatic effects of floaters may persist. For these patients, treatment options are available, of which the most commonly reported is vitrectomy. Other treatment modalities have also become more common, notably YAG vitreolysis. Selection of appropriate patients for surgery is often difficult, in part due to the relative lack of objective outcomes with which to measure both visual impairment and improvement post-procedure. Although well-tolerated, vitrectomy does carry with it risks, including iatrogenic retinal breaks, retinal detachment, and in phakic patients, subsequent cataract formation. Techniques such as small gauge vitrectomy, intraoperative examination and treatment of breaks or other worrying lesions, and careful consideration of the need for posterior vitreous detachment induction may help limit the incidence of these adverse events. For other treatment options such as YAG vitreolysis, research and clinical experience remain more limited, and as such the long-term efficacy and risks of these therapies are still unclear. Here, we review the evidence surrounding the role of vitrectomy and YAG vitreolysis in the treatment of vitreous floaters and potential means to minimize therapeutic complications.
Topics: Eye Diseases; Humans; Laser Therapy; Lasers, Solid-State; Vitrectomy; Vitreous Body
PubMed: 32097127
DOI: 10.1097/APO.0000000000000276 -
Ophthalmologica. Journal International... 2013The vitreous is involved in multiple diseases when an incomplete posterior vitreous detachment (PVD) occurs. An incomplete PVD can lead to several pathological... (Review)
Review
The vitreous is involved in multiple diseases when an incomplete posterior vitreous detachment (PVD) occurs. An incomplete PVD can lead to several pathological conditions. Such visually threatening conditions are traditionally of exclusive surgical interest. In contrast, pharmacological vitreolysis is the effort to reduce or eliminate the pathogenetic role of the vitreous solely by means of drug delivery. Here we aim to review and summarize the evidence available to date about this challenging new approach.
Topics: Enzymes; Humans; Vitreous Body; Vitreous Detachment
PubMed: 24029751
DOI: 10.1159/000354547 -
Journal of Biomedicine & Biotechnology 2012Fibronectin and laminin are clinically relevant plasmin receptors in the eye. Located at the vitreoretinal interface, they are cleaved by ocriplasmin (Microplasmin,... (Review)
Review
Fibronectin and laminin are clinically relevant plasmin receptors in the eye. Located at the vitreoretinal interface, they are cleaved by ocriplasmin (Microplasmin, ThromboGenics, Iselin, NJ), a novel ophthalmic medication. A series of clinical trials to study ocriplasmin for the treatment of vitreoretinal diseases such as vitreomacular traction, macular hole, and exudative age-related macular degeneration are underway. The results are promising and may impact patient care.
Topics: Animals; Drug Approval; Fibrinolysin; Humans; Peptide Fragments; Randomized Controlled Trials as Topic; Retinal Diseases; Vitreous Body
PubMed: 23193358
DOI: 10.1155/2012/354979 -
Translational Vision Science &... Jul 2022To develop a machine-learning image processing model for three-dimensional (3D) reconstruction of vitreous anatomy visualized with swept-source optical coherence...
PURPOSE
To develop a machine-learning image processing model for three-dimensional (3D) reconstruction of vitreous anatomy visualized with swept-source optical coherence tomography (SS-OCT).
METHODS
Healthy subjects were imaged with SS-OCT. Scans of sufficient quality were transferred into the Fiji is just ImageJ image processing toolkit, and proportions of the resulting stacks were adjusted to form cubic voxels. Image-averaging and Trainable Weka Segmentation using Sobel and variance edge detection and directional membrane projections filters were used to enhance and interpret the signals from vitreous gel, liquid spaces within the vitreous, and interfaces between the former. Two classes were defined: "Septa" and "Other." Pixels were selected and added to each class to train the classifier. Results were generated as a probability map. Thresholding was performed to remove pixels that were classified with low confidence. Volume rendering was performed with TomViz.
RESULTS
Forty-seven eyes of 34 healthy subjects were imaged with SS-OCT. Thirty-four cube scans from 25 subjects were of sufficient quality for volume rendering. Clinically relevant vitreous features including the premacular bursa, area of Martegiani, and prevascular vitreous fissures and cisterns, as well as varying degrees of vitreous degeneration were visualized in 3D.
CONCLUSIONS
A machine-learning model for 3D vitreous reconstruction of SS-OCT cube scans was developed. The resultant high-resolution 3D movies illustrated vitreous anatomy in a manner like triamcinolone-assisted vitrectomy or postmortem dye injection.
TRANSLATIONAL RELEVANCE
This machine learning model now allows for comprehensive examination of the vitreous structure beyond the vitreoretinal interface in 3D with potential applications for common disease states such as the vitreomacular traction and Macular Hole spectrum of diseases or proliferative diabetic retinopathy.
Topics: Humans; Imaging, Three-Dimensional; Machine Learning; Tomography, Optical Coherence; Vitrectomy; Vitreous Body
PubMed: 35802368
DOI: 10.1167/tvst.11.7.3