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QJM : Monthly Journal of the... Aug 2019
Topics: Diabetes Mellitus, Type 2; Eye Diseases; Humans; Male; Middle Aged; Vitreous Body
PubMed: 30690579
DOI: 10.1093/qjmed/hcz029 -
Ophthalmic Surgery, Lasers & Imaging... Oct 2018Vital dyes contain complex molecules with chromophores that stain living tissues and have greatly enhanced identification and removal of transparent vitreoretinal... (Review)
Review
Vital dyes contain complex molecules with chromophores that stain living tissues and have greatly enhanced identification and removal of transparent vitreoretinal tissues during surgery. Several "chromovitrectomy" dyes are frequently used by vitreoretinal specialists, including indocyanine green, trypan blue, brilliant blue G, and triamcinolone acetonide; other dyes are also under investigation. Trypan Blue was approved by the U.S. Food and Drug Administration (FDA) for epiretinal membrane removal, and preservative-free triamcinolone acetonide was approved by the FDA for intraocular use. However, currently available chromovitrectomy dyes have their limitations, and of particular concern for some of them is the possibility for acute and chronic toxicity to the neurosensory retina and retinal pigmented epithelium. The potentially irreversible acute toxicity and other limitations, such as lack of long-term safety profiles, highlight the need for further advancements. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:788-798.].
Topics: Coloring Agents; Humans; Indocyanine Green; Intraoperative Period; Macula Lutea; Retinal Diseases; Trypan Blue; Vitreoretinal Surgery; Vitreous Body
PubMed: 30395665
DOI: 10.3928/23258160-20181002-07 -
The New England Journal of Medicine Aug 2018
Topics: Diabetes Mellitus, Type 2; Eye Diseases; Female; Humans; Middle Aged; Visual Acuity; Vitreous Body
PubMed: 30134134
DOI: 10.1056/NEJMicm1712355 -
Der Ophthalmologe : Zeitschrift Der... Jul 2015
Topics: Aging; Animals; Humans; Retinal Diseases; Vitreous Body
PubMed: 26065526
DOI: 10.1007/s00347-015-0060-4 -
Survey of Ophthalmology 2017Positive vitreous pressure occurs during anterior segment intraocular surgery associated with acute hypotony and is characterized by forward displacement of the... (Review)
Review
Positive vitreous pressure occurs during anterior segment intraocular surgery associated with acute hypotony and is characterized by forward displacement of the lens-iris diaphragm with shallowing of the anterior chamber resistant to reformation, repeated iris prolapse, and, in severe cases, zonular rupture and vitreous or lens prolapse that can lead to a cascade of intraoperative complications. Positive vitreous pressure is particularly common during penetrating keratoplasty, conventional nuclear expression cataract extraction, and repair of anterior open-globe injury. Hypotony resulting from aqueous loss leads to elevated vitreous pressure from 3 possible causes: external scleral compression, acute intraocular intumescence, or rarely acutely increased vitreous volume. Understanding the pathophysiology of positive vitreous pressure helps in its prevention and management.
Topics: Anterior Chamber; Intraoperative Complications; Ocular Hypotension; Ophthalmologic Surgical Procedures; Vitreous Body
PubMed: 27751822
DOI: 10.1016/j.survophthal.2016.10.002 -
Der Ophthalmologe : Zeitschrift Der... Jul 2015Although numerous advances have been made in technology and techniques of pars plana vitrectomy and tamponades, there are still unsolved issues, such as proliferative... (Review)
Review
BACKGROUND
Although numerous advances have been made in technology and techniques of pars plana vitrectomy and tamponades, there are still unsolved issues, such as proliferative vitreoretinopathy (PVR), multiple retinal breaks and persistent hypotonia. All available internal tamponades (e.g, gases, oils and fluorocarbons) are hydrophobic, so they approximate the neurosensory retina to the retinal pigment epithelium due to buoyant force and surface tension. Even though these tamponade materials exhibit various beneficial attributes in the clinical application, the hydrophobic nature has clear disadvantages and compartmentalization and significant incidence of PVR development still occur.
RESULTS AND CONCLUSION
An ideal vitreous body substitute should mimic the native human vitreous body, in both form and function. Vitreous body substitutes, such as hydrogels fulfill the biophysical needs in a similar manner to the natural vitreous body by providing an internal tamponade effect through swelling pressure and viscosity. New approaches range from cross-linked semisynthetic to synthetic polymers. These hydrogels have a good biocompatibility, optical clarity, a refractive index and rheological properties that are similar to the natural human vitreous body and are able to act as anti-adhesive and anti-migrative agents and can therefore reduce PVR. Furthermore, hydrogels could also serve as controlled-release drug-delivery systems for anti-proliferative, neuroprotective or nutritive drugs.
Topics: Artificial Organs; Biomimetic Materials; Humans; Hydrogels; Prosthesis Design; Retina; Vitreous Body
PubMed: 26077344
DOI: 10.1007/s00347-015-0057-z -
Current Eye Research Apr 2021Research on the vitreous humor and development of hydrogel vitreous substitutes have gained a rapid increase in interest within the past two decades. However, the... (Review)
Review
Research on the vitreous humor and development of hydrogel vitreous substitutes have gained a rapid increase in interest within the past two decades. However, the properties of the vitreous humor and vitreous substitutes have yet to be consolidated. In this paper, the mechanical properties of the vitreous humor and hydrogel vitreous substitutes were systematically reviewed. The number of publications on the vitreous humor and vitreous substitutes over the years, as well as their respective testing conditions and testing techniques were analyzed. The mechanical properties of the human vitreous were found to be most similar to the vitreous of pigs and rabbits. The storage and loss moduli of the hydrogel vitreous substitutes developed were found to be orders of magnitude higher in comparison to the native human vitreous. However, the reported modulus for human vitreous, which was most commonly tested , has been hypothesized to be different . Future studies should focus on testing the mechanical properties of the vitreous or . In addition to its mechanical properties, the vitreous humor has other biotransport mechanisms and biochemical functions that establish a redox balance and maintain an oxygen gradient inside the vitreous chamber to protect intraocular tissues from oxidative damage. Biomimetic hydrogel vitreous substitutes have the potential to provide ophthalmologists with additional avenues for treating and controlling vitreoretinal diseases while preventing complications after vitrectomy. Due to the proximity and interconnectedness of the vitreous humor to other ocular tissues, particularly the lens and the retina, more interest has been placed on understanding the properties of the vitreous humor in recent years. A better understanding of the properties of the vitreous humor will aid in improving the design of biomimetic vitreous substitutes and enhancing intravitreal biotransport.
Topics: Biocompatible Materials; Biological Transport; Biomechanical Phenomena; Biomimetic Materials; Humans; Hydrogels; Viscoelastic Substances; Vitreous Body
PubMed: 33040616
DOI: 10.1080/02713683.2020.1826977 -
Developments in Ophthalmology 2016Normal retina contains neuroretina and retinal pigment epithelium. The neuroretina consists of outer and inner segments of photoreceptors (rods and cones), external... (Review)
Review
Normal retina contains neuroretina and retinal pigment epithelium. The neuroretina consists of outer and inner segments of photoreceptors (rods and cones), external limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, nerve fiber layer and internal limiting membrane. There is a broad spectrum of retinal pathology including congenital abnormalities, dystrophies, degenerations (notably age-related macular degeneration), retinal vascular diseases, toxicities, inflammatory diseases, neoplasms, retinal detachment, trauma and retinal involvement of systemic diseases. This chapter presents a few major pathological processes in retinal diseases, especially processes that are amenable to pharmacotherapeutics.
Topics: Humans; Retina; Retinal Diseases; Tissue Adhesions; Vitreous Body
PubMed: 26502225
DOI: 10.1159/000431128 -
PloS One 2023To explore the changes in vitreous body after vitreous hemorrhage and assess its prognosis from the perspective of vitreoretinal interface.
PURPOSE
To explore the changes in vitreous body after vitreous hemorrhage and assess its prognosis from the perspective of vitreoretinal interface.
METHODS
The experiment was performed on 32 New Zealand rabbits (64 eyes), weighing 2500-3000 g for 4 months and unlimited gender, which was injected with 0.2 mL of autologous blood into the center of vitreous cavity-the study group (right eyes), and the control one was treated in the same manner with equal volumes of saline. The rabbits were randomly and equally divided into the following four batches according to the days of observation: Days 3, 7, 14, and 30 after injection. IOP and severity grading were evaluated before rabbits' execution and eyeballs were enucleated. The anterior segment was separated to flow out the vitreous body naturally to detect the liquefaction degree and viscosity. Then, chemical composition of electrolytes, PCT and bFGF were determined by colorimetry and enzyme-linked immunosorbent assay (ELISA). Finally, the incidence of posterior vitreous detachment (PVD) was observed after vitreous sampled. The studies were double-blind.
RESULTS
After injection, the extent of vitreous opacity and coagulum size decreased over time. Both the degree of liquefaction and the length of tow differed significantly between two groups at different time points (all p < 0.001). The liquefaction degree in the study group rose obviously from the Day 14, which the viscosity declined significantly on the initial time. Biochemical markers fluctuated temporarily, except for basic fibroblast growth factor (bFGF), which continued to rise and was correlated with the liquefaction degree (r = 0.658, p < 0.001). Besides, the incidence of PVD increased from the 14th day (p < 0.05), and it was highly positively correlated with the number of macrophages (r = 0.934; p < 0.001).
CONCLUSION
After vitreous hemorrhage, the changes of the vitreous body are relatively minor earlier (2-4 weeks), but irreversible later. Specifically, the degree of liquefaction increases with a decrease in viscosity, and the chemotaxis of macrophages and bFGF induce incomplete PVD.
Topics: Animals; Rabbits; Injections; Interdisciplinary Studies; Vitreous Body; Vitreous Detachment; Vitreous Hemorrhage
PubMed: 36745670
DOI: 10.1371/journal.pone.0281165 -
Current Opinion in Ophthalmology May 2021Symptomatic vitreous opacities are increasingly recognized as a significant burden to patient well-being. There is growing interest in the use of vitrectomy or laser... (Review)
Review
PURPOSE OF REVIEW
Symptomatic vitreous opacities are increasingly recognized as a significant burden to patient well-being. There is growing interest in the use of vitrectomy or laser treatment to address these problems. This review is intended to update current assessment, management, and risks of treatment for persistent severely symptomatic vitreous opacities.
RECENT FINDINGS
Despite studies showing the value of quantitative ultrasound, reading speed measurements, and contrast sensitivity for assessing dysfunction caused by vitreous opacities, the decision of whether to proceed with surgery remains a very subjective, clinical one. Visual Function Questionnaire-25 score studies show a very large improvement postvitrectomy consistent with relief from symptoms and patient satisfaction. The risk of retinal tear and detachment appears to be higher than in most conditions treated with vitrectomy.
SUMMARY
Vitrectomy for the management of severe vitreous opacities is increasingly accepted because of the tremendous relief of symptoms reported by patients. The risks of retinal tear and detachment remain a concern, particularly in patients who have an attached posterior hyaloid. Yttrium-aluminum-garnet laser treatment of floaters may offer benefit in a subset of patients but appears to be less definitive than vitrectomy, and also may carry significant risk.
Topics: Eye Diseases; Humans; Laser Therapy; Lasers, Solid-State; Vitrectomy; Vitreous Body
PubMed: 33710011
DOI: 10.1097/ICU.0000000000000752