scholarly journals Vitreous function and intervention of it with vitrectomy and other modalities

2021 ◽  
Vol 14 (10) ◽  
pp. 1610-1618
Author(s):  
Yao Zong ◽  
◽  
Yan-Nian Hui ◽  
Keyword(s):  
Oxygen Tension ◽  
Open Angle Glaucoma ◽  
Vitreous Body ◽  
Oxygen Metabolism ◽  
Scleral Buckling ◽  
Metabolic Abnormalities ◽  
Anterior Chamber Angle ◽  
Conventional Procedure ◽  
High Incidence ◽  
Stress Damage

The vitreous body, the largest intraocular component, plays a key role in eye development, refraction, cell barrier function, oxygen metabolism and the pathogenesis of assorted diseases. Age, refraction and systemic diseases can cause vitreous metabolic abnormalities. With the continuous development of vitrectomy techniques and equipment, vitreous injections and vitrectomies have increased over the recent decades. However, the normal oxygen tension gradient in the vitreous helps to protect the lens and anterior chamber angle from oxidative stress damage, whereas the increased vitreous oxygen tension around lens and the trabecular meshwork after vitrectomy may lead to postoperative nuclear cataract and a high incidence of open angle glaucoma. As a conventional procedure, scleral buckling holds several advantages over vitrectomy in selected cases. This review raises concerns regarding the function of the vitreous, and encourages conducting vitreous interventions prudently.

Biomedical Materials to Repair Retinal Detachments

1985 ◽  
Vol 55 ◽  
Author(s):  
Miguel F. Refojo
Keyword(s):  
Retinal Detachment ◽  
Silicone Rubber ◽  
Methyl Acrylate ◽  
Silicone Oil ◽  
Vitreous Body ◽  
Light Sensitivity ◽  
Scleral Buckling ◽  
Intraocular Injection ◽  
Other Substances

ABSTRACTImplants are essential for the repair of retinal detachments. The implant buckles the wall of the eye and apposes the detached retina with the choroid, thus restoring light sensitivity to the retina. The scleral buckling also relieves traction on the retina from a shrinking vitreous body. The implant materials most commonly used are solid silicone rubber and silicone sponges, but both types have some disadvantages. A poly(hydroxyethyl acrylate-co-methyl acrylate) hydrogel implant with improved properties of softness and antibiotic absorption is also available for retinal detachment surgery. Proliferative vitreoretinopathy involves various conditions of retinal detachment complicated by vitreous fibrosis, which, after vitrectomy, may be treated with intraocular injection of fluids that support the retina against the choroid. For conditions requiring a long-term implant, silicone oil although controversial is the material of choice. Many other substances have been investigated but none better has yet been found.

scholarly journals Pars Plana Vitrectomy and the Risk of Ocular Hypertension and Glaucoma: Where Are We?

2020 ◽  
Vol 9 (12) ◽  
pp. 3994
Author(s):  
Tommaso Rossi ◽  
Guido Ripandelli
Keyword(s):  
Anterior Chamber ◽  
Ocular Hypertension ◽  
Oxygen Tension ◽  
Pars Plana Vitrectomy ◽  
Open Angle Glaucoma ◽  
Crystalline Lens ◽  
Cataract Extraction ◽  
Oxygen Scavenger ◽  
Clinical Series ◽  
Pars Plana

Purpose is to review the pathogenic mechanism for ocular hypertension and glaucoma development after pars plana vitrectomy. Both acute and chronic causes are considered, and special attention is paid to the theories and clinical evidence on the risk of developing Open Angle Glaucoma (OAG) after Pars Plana Vitrectomy (PPV). Most existing scientific literature on the issue agree on the role of ascorbate as an oxygen scavenger within the vitreous chamber. Oxygen tension in the vitreous and anterior chamber is maximum inn proximity of the retinal surface and endothelium, respectively and steeply decreases toward the lens, on both sides, and trabecular meshwork. Vitreous removal and, to a lesser extent, liquefaction, greatly reduces oxygen tension gradient in vitreous chamber while cataract extraction has similar effects on anterior chamber oxygen gradients. Oxygen derivatives originated from the cornea and retina are actively reduced by the vitreous gel and/or the crystalline lens. Vitreous removal and cataract extraction reduce drastically this function. Most reported clinical series confirm this hypothesis although protocol difference and follow-up length greatly impact the reliability of results.

Retinopathy of Prematurity

1989 ◽  
Vol 83 (10) ◽  
pp. 500-504
Author(s):  
E. Trief ◽  
R. Duckman ◽  
A.R. Morse ◽  
R.K. Silberman
Keyword(s):  
Retinopathy Of Prematurity ◽  
Low Birthweight ◽  
Scleral Buckling ◽  
Structured Learning ◽  
Entire Family ◽  
Oxygen Administration ◽  
Visual Damage ◽  
High Incidence ◽  
Total Blindness ◽  
Impaired Children

Retinopathy of prematurity (ROP), formerly called retro-lental fibroplasia (RLF), has increased in the 1980s due to a high incidence of premature, low birthweight infants. Apparently, oxygen administration alone does not account for all these ROP babies. Birth-weight, gestational age, and duration of administration of oxygen are primary contributors to ROP development. The stages of severity range from no visual damage to total blindness. Treatments are either pharmacological or surgical. Vitamin E therapy, photocoagulation procedures, cryotherapy, scleral buckling procedures, and vitrectomy are common treatments, but none is totally successful in ameliorating this condition. The educational problems of children with ROP parallel those of other visually impaired children, with deficits found primarily in exploration, mobility, and language. Referral to early intervention programs can provide a comprehensive structured learning situation and support to the entire family.

scholarly journals The Effects of Capillary Transit Time Heterogeneity (CTH) on Brain Oxygenation

2015 ◽  
Vol 35 (5) ◽  
pp. 806-817 ◽  
Author(s):  
Hugo Angleys ◽  
Leif Østergaard ◽  
Sune N Jespersen
Keyword(s):  
Blood Flow ◽  
Diffusion Equation ◽  
Oxygen Tension ◽  
Transit Time ◽  
Time Distribution ◽  
Ischemia Reperfusion ◽  
Oxygen Metabolism ◽  
Tissue Oxygen Tension ◽  
Tissue Oxygen ◽  
Transit Time Distribution

We recently extended the classic flow–diffusion equation, which relates blood flow to tissue oxygenation, to take capillary transit time heterogeneity ( CTH) into account. Realizing that cerebral oxygen availability depends on both cerebral blood flow ( CBF) and capillary flow patterns, we have speculated that CTH may be actively regulated and that changes in the capillary morphology and function, as well as in blood rheology, may be involved in the pathogenesis of conditions such as dementia and ischemia-reperfusion injury. The first extended flow–diffusion equation involved simplifying assumptions which may not hold in tissue. Here, we explicitly incorporate the effects of oxygen metabolism on tissue oxygen tension and extraction efficacy, and assess the extent to which the type of capillary transit time distribution affects the overall effects of CTH on flow–metabolism coupling reported earlier. After incorporating tissue oxygen metabolism, our model predicts changes in oxygen consumption and tissue oxygen tension during functional activation in accordance with literature reports. We find that, for large CTH values, a blood flow increase fails to cause significant improvements in oxygen delivery, and can even decrease it; a condition of malignant CTH. These results are found to be largely insensitive to the choice of the transit time distribution.

scholarly journals Prevalence and associated factors of glaucoma in the Russian Ural Eye and Medical Study

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mukharram M. Bikbov ◽  
Timur R. Gilmanshin ◽  
Rinat M. Zainullin ◽  
Gyulli M. Kazakbaeva ◽  
Inga I. Arslangareeva ◽  
...  
Keyword(s):  
Associated Factors ◽  
Open Angle Glaucoma ◽  
Population Based ◽  
Older Age ◽  
Angle Closure ◽  
Glaucomatous Optic Neuropathy ◽  
Anterior Chamber Angle ◽  
Asian Populations ◽  
Medical Study ◽  
Blind Individuals

AbstractTo assess the prevalence and associated factors of glaucoma in a Russian population. The population-based Ural Eye and Medical Study included 5899 (mean age 59.0 ± 10.7 years; range 40–94 years). Glaucomatous optic neuropathy was diagnosed using International Society of Geographical and Epidemiological Ophthalmology (ISGEO) criteria. Among 5545 participants with assessable optic disc photographs, 246 individuals [4.4%; 95% confidence interval (CI) 3.9, 5.0] had glaucoma, with open-angle glaucoma (OAG) in 177 individuals (3.2%; 95% CI 2.7, 3.7) and angle-closure glaucoma (ACG) in 69 individuals (1.2; 95% CI 1.0, 1.5), with IOP > 21 mmHg in 79 (32.1%) patients, and with 80 (32.5%) patients on glaucoma therapy. Glaucoma prevalence increased from 3/485 (0.6%; 95% CI 0.0, 1.3) in the age group of 40–45 years to 33/165 (20.0%; 95% CI 13.8, 26.2) in the group aged 80 + years. Higher OAG prevalence correlated with older age [odds ratio (OR) 1.07; 95% CI 1.04, 1.09; P < 0.001], longer axial length (OR 1.36; 95% CI 1.17, 1.58; P < 0.001), higher intraocular pressure (IOP) (OR 1.18; 95% CI 1.13, 1.23; P < 0.001), higher stage of lens pseudoexfoliation (OR 1.26; 95% CI 1.08, 1.47; P = 0.004) and lower diastolic blood pressure (OR 0.98; 95% CI 0.96, 0.99; P = 0.035). Higher ACG prevalence correlated with older age (OR 1.07; 95% CI 1.03, 1.11; P < 0.001), narrower anterior chamber angle (OR 0.81; 95% CI 0.77, 0.86; P < 0.001), and higher IOP (OR 1.30; 95% CI 1.23, 1.38; P < 0.001). Glaucoma caused moderate to severe vision impairment (MSVI) in 9 (4.9%; 95% CI 1.8, 8.1) out of 184 individuals with MSVI (OAG, n = 7; ACG, n = 2), and blindness in one (9.1%) of 11 blind individuals. In this population from Russia, two thirds of glaucoma patients were not on therapy, and in two thirds of the glaucoma patients IOP was ≤ 21 mmHg. Otherwise, glaucoma prevalence, OAG-to-ACG ratio, and glaucoma associations did not differ markedly from Caucasian and East Asian populations.

Metabolic abnormalities in patients with primary open-angle glaucoma

2001 ◽  
Vol 79 (2) ◽  
pp. 129-132 ◽  
Author(s):  
Moses Elisaf ◽  
George Kitsos ◽  
Eleni Bairaktari ◽  
Rigas Kalaitzidis ◽  
Christos Kalogeropoulos ◽  
...  
Keyword(s):  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Metabolic Abnormalities ◽  
Open Angle

scholarly journals Oxidative Stress and Diabetic Retinopathy

2007 ◽  
Vol 2007 ◽  
pp. 1-12 ◽  
Author(s):  
Renu A. Kowluru ◽  
Pooi-See Chan
Keyword(s):  
Oxidative Stress ◽  
Clinical Trials ◽  
Animal Studies ◽  
Antioxidant Defense System ◽  
Oxygen Metabolism ◽  
Developed Countries ◽  
Causal Link ◽  
Diabetic Patients ◽  
Metabolic Abnormalities ◽  
Beneficial Effects

Oxygen metabolism is essential for sustaining aerobic life, and normal cellular homeostasis works on a fine balance between the formation and elimination of reactive oxygen species (ROS). Oxidative stress, a cytopathic consequence of excessive production of ROS and the suppression of ROS removal by antioxidant defense system, is implicated in the development of many diseases, including Alzheimer's disease, and diabetes and its complications. Retinopathy, a debilitating microvascular complication of diabetes, is the leading cause of acquired blindness in developed countries. Many diabetes-induced metabolic abnormalities are implicated in its development, and appear to be influenced by elevated oxidative stress; however the exact mechanism of its development remains elusive. Increased superoxide concentration is considered as a causal link between elevated glucose and the other metabolic abnormalities important in the pathogenesis of diabetic complications. Animal studies have shown that antioxidants have beneficial effects on the development of retinopathy, but the results from very limited clinical trials are somewhat ambiguous. Although antioxidants are being used for other chronic diseases, controlled clinical trials are warranted to investigate potential beneficial effects of antioxidants in the development of retinopathy in diabetic patients.

Cystoid Macular Edema Associated with Latanoprost Therapy in a Pseudophakic Vitrectomized Patient after Removal of Silicone Oil Endotamponade

2003 ◽  
Vol 13 (2) ◽  
pp. 221-222 ◽  
Author(s):  
M. Jäger ◽  
J.B. Jonas
Keyword(s):  
Visual Acuity ◽  
Cataract Surgery ◽  
Macular Edema ◽  
Cystoid Macular Edema ◽  
Silicone Oil ◽  
Open Angle Glaucoma ◽  
Vitreous Body ◽  
Corticosteroid Treatment ◽  
Posterior Chamber ◽  
Eye Drops

Purpose To describe the occurrence of cystoid macular edema in a pseudophakic vitrectomized patient following use of latanoprost (0.005%). Methods A 58-year-old patient underwent routine cataract surgery with posterior chamber lens implantation complicated by rhegmatogenous retinal detachment three months later. A pars plana vitrectomy was performed with silicone oil endotamponade which was removed six months later. Five months after oil removal, the patient presented with secondary open-angle glaucoma treated with latanoprost 0.005% eye drops once daily. Results Two weeks after initiation of latanoprost treatment, visual acuity dropped from 0.8 to 0.3 due to cystoid macular edema confirmed by fluorescein angiography. After discontinuing latanoprost therapy and with topical corticosteroid treatment, cystoid macular edema slowly resolved, and within 6 months, visual acuity improved to 0.8. Conclusions Despite its marked ocular hypotensive effect, latanoprost should be carefully used in patients after uncomplicated cataract surgery if the vitreous body was removed by pars piana vitrectomy.

scholarly journals A Case of Intraocular Erosion and Intrusion by an Arruga Suture

2016 ◽  
Vol 7 (1) ◽  
pp. 174-178 ◽  
Author(s):  
Takakuni Kitagaki ◽  
Seita Morishita ◽  
Ryohsuke Kohmoto ◽  
Masanori Fukumoto ◽  
Hiroyuki Suzuki ◽  
...  
Keyword(s):  
Open Angle Glaucoma ◽  
Pigment Cell ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Vitreous Hemorrhage ◽  
Scleral Buckling ◽  
Eye Drops ◽  
Blurred Vision ◽  
Anterior Portion ◽  
Filamentous Material

Purpose: To report a case of intraocular erosion and intrusion by an Arruga suture. Case Report: This study involved a 62-year-old male who had undergone scleral buckling surgery 40 or more years ago at another hospital for rhegmatogenous retinal detachment, as well as trabeculectomy 20 years ago for primary open-angle glaucoma, in his left eye at the same hospital. However, he recently became aware of blurred vision in that eye. Upon examination, iritis was observed in the anterior portion of his left eye, as well as a great number of pigment cell keratoprecipitates on the posterior surface of the cornea. In the ocular fundus, extensive atrophy of the retinal pigment epithelium and partial hyperpigmentation was observed, accompanied by subretinal strands, yet the retina remained attached. Around the entire peripheral area of the retina we observed a ring-shaped protrusion, but we also saw a shiny, filamentous material in the vitreous cavity that penetrated the sclera and choroid, completely extending from the 4- to 8-o'clock position of the scleral buckle protrusion. To treat the iritis in the patient's left eye, we began to administrate low-concentration steroid eye drops, after which the inflammation disappeared. Conclusion: In this study, we experienced a case of intraocular erosion and intrusion by an Arruga suture, and opted to treat the patient with steroid eye drops and conservative follow-up observations unless retinal redetachment and/or vitreous hemorrhage occurs.

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