Reflections on subretinal fluid release.
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Body Fluids↗
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Results for “Intraocular fluid”
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[Changes in acoustico-vestibular function in glaucoma patients].
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Adult↗
Bullous keratopathy accompanying essential iris atrophy: response to lowered intraocular pressure.
We present a patient with essential iris atrophy who was normotensive and yet had corneal edema and bullous keratopathy which cleared upon lowering the intraocular pressure. It is proposed that in this patient the endothelial functional status was so compromised that it could not handle the amount of fluid driven into the cornea by a normal intraocular pressure. A more favorable balance between intraocular pressure and endothelial functional status was obtained by lowering the intraocular pressure with acetazolamide and timolol.
Acetazolamide↗
A pneumovitrector for the diagnostic biopsy of the vitreous.
A full-function vitrectomy instrument (pneumovitrector) developed by the author is described. This instrument is composed of an aspirating and cutting system combined with an infusion line for injecting air or gas into the vitreous cavity. Simultaneous injection of gas and removal of the vitreous pneumovitrectomy allows for a large vitreous biopsy specimen that has not been diluted with infusion fluid and does not reduce the intraocular pressure. A biopsy of the vitreous is performed for the diagnosis of intraocular infection and ocular involvement in reticulum cell sarcoma (non-Hodgkin's lymphoma). While aspiration of a small amount of liquid vitreous is often sufficient for the diagnosis of bacterial endophthalmitis, a larger volume of liquid and solid vitreous is needed for the establishment of diagnoses such as fungal endophthalmitis and intraocular lymphoma. Diagnostic vitrectomy is performed using either a 20-gauge needle or a 22-gauge needle or a miniaturized vitrectomy system. In the latter case, vitrectomy instruments are often combined with either an infusion cannula or an infusing fiber optic light probe. In most situations, 0.1 to 0.2 ml of vitreous is removed prior to injection and replacement of the volume of the vitreous , in order to obtain the maximum amount of undiluted vitreous for culture or histologic evaluation. Although a complete vitrectomy can be performed and the aspirate collected in the vitrectomy cassette can be spun down to obtain solid material, this procedure is generally done in the operating room. Aspiration of the vitreous for the biopsy without simultaneous replacement of the vitreous volume limits the amount of biopsy specimen that can be taken and is accompanied by the collapse of the eye as a result of hypotony. To overcome this problem, a miniaturized instrument (pneumovitrector) has been developed by this author.
Biopsy↗
[Retinal detachment and posterior lens luxation. Value of liquid perfluorocarbons].
PURPOSE: The purpose of this study is to review the benefits of perfluorocarbon liquids in the surgical treatment of retinal detachment with posterior lens dislocation. METHODS: Three cases of retinal detachment occurring in the presence of a posteriorly dislocated intraocular lens were managed with vitrectomy, fluid perfluorocarbon, scleral buckling and silicone oil injection. The dislocated lens were removed by anterior approach. RESULTS: In all cases a successful retinal reattachment was obtained after one or two surgical procedures.
Aged↗
The correcting influence of the locus ceruleus on ophthalmic hypertension of hypothalamic origin.
Chronic experiments were performed on rabbits to study changes in intraocular pressure, the coefficient of flow conductivity, and the chamber fluid minute volume during chronic emotional stress induced by long-lasting repeated electrical stimulation of the ventromedial nucleus of the hypothalamus alone and in combination with electrical stimulation of the locus ceruleus and central gray matter of the periacqueductal matter. Stimulation of the ventromedial nucleus of the hypothalamus was accompanied by an increase in intraocular pressure, an increase in the production of eye chamber fluid, and a decrease in the coefficient of flow conductivity. Electrical stimulation of the locus ceruleus and central gray matter of the periacqueductal matter led to less marked increases in intraocular pressure. Combined stimulation of the hypothalamus and locus ceruleus led to normalization of intraocular pressure due to a reduction in the volume of chamber fluid and an increase in the coefficient of flow conductivity.
Animals↗
Air travel and intraocular gas.
The safety of air travel for persons with intraocular gas after ocular surgery has been in question since the mid 1970s, when the use of intraocular gases after vitrectomy became widespread. After vitrectomy, air-fluid exchange was performed on six Rhesus monkeys. During simulated air travel in an altitude chamber, intraocular pressure rose an average of 42 mmHg with intraocular air volumes as small as 0.25 cc. Hypotony was observed after return to ground level in all cases. Transient central retinal artery occlusion and pupillary block was observed. Patient safety and comfort is endangered during air travel with very small volumes of intraocular gas.
Aircraft↗
Treatment of postvitrectomy fibrin formation with intraocular tissue plasminogen activator.
Twenty-five micrograms of human recombinant tissue plasminogen activator (tPA) was injected intracamerally into the eyes of three aphakic patients who developed severe intraocular fibrin formation within 24 hours after vitrectomy surgery. Fluid obtained from gas-fluid exchange specimens taken 24 hours after tPA injection was analyzed for tPA by an enzyme-linked immunosorbent assay and a spectrophotometric solid-phase fibrin assay. In each of the three patients, complete fibrin resolution occurred within four hours after the tPA injection. There were no complications associated with the intraocular tPA injections. There was measurable tPA activity 24 hours after the initial injection ranging from 0.23 to 1.4 micrograms. In contrast, tPA was undetectable in gas-fluid exchange specimens obtained from seven patients who did not receive intraocular tPA injections. Intraocular tPA is an effective means of treating postvitrectomy fibrin formation in selected aphakic patients.
Adolescent↗
Biocompatibility response to modified Baerveldt glaucoma drains.
Glaucoma implants are designed to increase fluid outflow from the eye in order to decrease intraocular pressure and prevent damage to the optic nerve. The implant consists of a silicone tube that is inserted into the anterior chamber at one end and is attached at the other end to a silicone plate that is sutured to the outside of the globe beneath the conjunctiva. The glaucoma "implant" becomes a "drain" over the first 3 to 6 postoperative weeks as the silicone plate is enclosed by a fibrous capsule that allows a space to form into which fluid can drain and from which fluid can be absorbed by the surrounding tissues. Ideally, the size and thickness of the capsule (the filtering bleb) that surrounds the plate is such that the amount of fluid that passes through the capsule is identical to the amount of fluid produced by the eye at an intraocular pressure of 8 to 14 mmHg. The most common long-term complication of these implants is failure of the filtering bleb 2 to 4 years after surgery due to the formation of a thick fibrous capsule around the device. Micromovement of the smooth drainage plate against the scleral surface may be integral to the mechanism of glaucoma implant failure by stimulating low-level activation of the wound healing response, increased collagen scar formation, and increased fibrous capsule thickness. To test this hypothesis, we modified seven Baerveldt implants by adding porous cellular ingrowth material to the posterior surface of the drainage plate. Seven modified and five unmodified implants were placed in adult rabbit eyes. After 6 months, we found that the fibrous capsule around the modified implants was significantly thinner than the capsule surrounding the unmodified implants (p < 0.05), particularly on the surface between the porous ingrowth material and the sclera (p < 0.05). Although type I collagen predominated in the fibrous capsules around both types of implants, the amount of type III collagen in the capsules around the modified implants was significantly less than the amount around the unmodified implants (p < 0.05). We believe that these data suggest a reduction in the wound healing response to the modified implants, with greater stability of capsule thickness. Long-term studies are needed to verify that the stability of the capsules around the modified implants persists over a period of years, in which case this type of modification may prove useful in prolonging the functional life of these devices in the surgical treatment of glaucoma.
Animals↗
Blood circulation and fluid dynamics in the eye.
The nutrition of the intraocular tissues is accomplished by the retinal vessels, the uveal vessels, and by the aqueous humor. Both morphologically and physiologically the retinal vessels are similar to those in the brain. The endothelial cells of the capillaries are attached to each other by tight junctions, the resistance vessels respond poorly to a large number of drugs, and the blood flow through the retina is autoregulated and very little affected by the sympathetic nervous system. The blood vessels of the iris also have morphological and permeability characteristics similar to those in the brain but they are under a strong influence from the sympathetic nerves and react to many drugs. The blood flow is autoregulated. The blood vessels of the choroid and the ciliary processes are similar to those in the small intestine and in the kidney. The endothelial cells of the capillaries are fenestrated; the vessels respond to sympathetic nervous stimulation and to a large number of vasoactive drugs. Autoregulation of the blood flow is intermediate in the ciliary body and very poor or absent in the choroid...
Animals↗
Epithelial-mesenchymal transition in proliferative vitreoretinopathy: intermediate filament protein expression in retinal pigment epithelial cells.
PURPOSE: To improve our understanding of how retinal pigment epithelial (RPE) cells behave in vivo and to establish similarities with dedifferentiation and adaptive events observed in RPE cells cultured under simulated intraocular pathologic conditions. At the same time, to examine the origin of epithelioid-shaped and fibroblast/fusiform-shaped cells in epiretinal membranes (ERM) from proliferative vitreoretinopathy (PVR). METHODS: Cells of ERM were studied by electron-immunocytochemical techniques, using simple, double, and triple immunostaining for cytokeratins (CK), vimentin (Vim), and glial fibrillary acidic protein (GFAP). Ultrastructural morphology analysis was also carried out. Adult human RPE cells were obtained and cultured with normal and pathologic vitreous from proliferative vitreoretinal disorders, subretinal fluid aspirates from retinal detachment, and normal human serum. Their cytoskeleton was fractionated at 7 (early cultures) and 24 (late cultures) days of culture, electrophoresed, immunoblotted for intermediate filament proteins, and quantified by densitometric analysis for each condition. Changes in phenotype characteristics were also evaluated. RESULTS: Epithelioid-shaped and fibroblast/fusiform-shaped cells, resembling RPE cells, expressed CK-Vim-GFAP simultaneously as intermediate filament proteins in their cytoskeleton. RPE cells in culture also expressed CK-Vim-GFAP and changed from an epithelial shape to a migratory fibroblast/fusiform-shaped phenotype in the presence of subretinal fluid aspirates and pathologic vitreous from proliferative intraocular disorders. In simulated cultures of proliferative intraocular disorders, cells decreased or retained their CK7, CK8, and CK18, retained Vim, and increased CK19 and GFAP, while their mesenchymal morphology became clearer over time. CONCLUSIONS: Studies of intermediate filament proteins in vivo suggest that dedifferentiation occurs in RPE cells in ERM. Dedifferentiated RPE cells may be responsible for epithelioid-like and fibroblast/fusiform-like cells. Furthermore, changes in intermediate filament protein levels were observed in RPE cells in simulated cultures of proliferative intraocular disorders. These changes were linked to cells acquiring a mesenchymal migratory, phenotype. Results indicate that the dedifferentiation of RPE cells occurs both in vivo and in vitro and that it can be explained as an epithelial-mesenchymal transition.
Adult↗
Imaging interface fluid after laser in situ keratomileusis with corneal optical coherence tomography.
A 41-year-old myopic patient who had laser in situ keratomileusis 6 months earlier was treated for a complete retinal detachment (RD) with proliferative vitreoretinopathy. Surgical treatment consisted of an encircling band, pars plana vitrectomy, and silicone oil filling. Postoperatively, the patient developed marked corneal edema with no increase in intraocular pressure (IOP) as measured by applanation tonometry. Interface fluid was confirmed by corneal optical coherence tomography. Quantification of the corneal structures revealed that corneal edema was in the residual posterior stroma predominantly. The epithelial and flap thickness did not change significantly. The case demonstrated that after vitreoretinal surgery for RD repair, transient corneal endothelial cell dysfunction developed, causing marked edema of the posterior corneal stroma and interface fluid accumulation. However, an increase in IOP cannot be excluded.
Adult↗
Management of macular hole and submacular hemorrhage in the same eye.
BACKGROUND: To report the management of patients with a macular hole and submacular hemorrhage in the same eye. METHODS: Case reports of two eyes of two patients undergoing pars plana vitrectomy (PPV), subretinal injection of tissue plasminogen activator (t-PA) and air-fluid exchange to displace a submacular hemorrhage. In one eye with a submacular hemorrhage due to age-related macular degeneration, a macular hole formed during subretinal t-PA injection. In another patient with a submacular hemorrhage due to a ruptured retinal arterial macroaneurysm (RAM), a sub-internal limiting membrane (ILM) hemorrhage was noted, and a macular hole was found after peeling the ILM, overlying the subretinal hemorrhage. RESULTS: In the first case, after 45 min was allowed for the subretinal clot to liquefy, the macular hole was noted to be closed. A partial air-fluid exchange was performed and the patient was positioned upright, to displace the submacular hemorrhage and tamponade the macular hole. Two weeks later, visual acuity had improved from 20/400 with eccentric viewing to 20/100, the macular hole was closed by optical coherence tomography, and the patient subsequently underwent two sessions of verteporfin photodynamic therapy (PDT) to treat choroidal neovascularization detected by fluorescein angiography. At last follow-up 7 months after surgery, vision was 20/200, the CNV was active angiographically, and another session of PDT was performed. In the second case, PPV was combined with phacoemulsification and intraocular lens implantation. An 80% air-fluid exchange was performed after injecting the subretinal t-PA, the air was exchanged for 14% perfluoropropane gas, and the patient was positioned upright. Visual acuity improved from 20/400 to 20/200 at last follow-up 4 months after surgery, with the RAM spontaneously sclerosed and the macular hole closed clinically and angiographically. CONCLUSIONS: Intraoperative evacuation of subretinal hemorrhage is not necessary in cases with coexisting macular hole and submacular hemorrhage. The submacular hemorrhage can be displaced using air or gas, and the bubble can be used to tamponade the macular hole.
Aged↗
De-misting condensation on intraocular lenses.
BACKGROUND: Condensation occurs rapidly on intraocular lenses (IOLs), particularly silicone IOLs, after vitrectomy and fluid-air exchange in the presence of a posterior capsulotomy and severely limits the surgeon's view of the retina. This study investigated the value of heating contact lens irrigation fluid to prevent condensation on IOLs. DESIGN: An experimental in vitro study and a noncomparative interventional case series. PARTICIPANTS: Five control eyes had temperature measurements during fluid-air exchanges. Two patients with silicone IOLs and posterior capsulotomies underwent a vitrectomy involving a fluid-air exchange with heated contact lens fluid. METHODS: An in vitro model allowed monitoring of temperature and humidity changes during condensation formation on four different IOL materials. Adjusting variables to promote evaporation rather than condensation was achieved in vitro. In vivo, intraocular temperatures were measured at various stages of five vitrectomies involving a fluid-air exchange. Finally, in two in vivo cases a blood warmer was used to heat the accessory contact lens irrigation fluid during the vitrectomy and fluid-air exchange. MAIN OUTCOME MEASURES: Successful prevention of condensation on the silicone IOL during the fluid-air exchange. RESULTS: Anterior segment temperature influences the IOL temperature, such that when it is higher than the posterior segment temperature, condensation does not form and evaporation is promoted. In vivo the temperatures in the eye are hypothermic throughout the vitrectomy. At fluid-air exchange the posterior segment heats rapidly as irrigation ceases and low specific heat gas enters. Finally, in two in vivo cases with silicone IOLs, condensation was predicted then prevented by our intervention for the duration of the fluid-air exchange. CONCLUSIONS: Heating the anterior segment by conduction from warmed irrigation fluid flowing through the irrigating contact lens represents a cheap, noninvasive, and safe means to prevent condensation on IOL materials.
Body Temperature↗
INTRAOCULAR PRESSURE CHANGES DURING ARTIFICIAL KIDNEY THERAPY.
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Body Fluids↗
Subretinal fluid analysis in the diagnosis of choroidal tuberculosis.
BACKGROUND: Diagnosis of intraocular tuberculosis is often difficult. A choroidal granulomalike lesion suspected to be the result of tuberculosis could be of other inflammatory, infective, or neoplastic causes. We report two cases in which a choroidal granuloma with exudative retinal detachment was diagnosed as tuberculosis by the detection of acid-fast bacilli in subretinal fluid. METHODS: Interventional case series. RESULTS: Two female patients had choroidal granulomas with surrounding exudative retinal detachment. Detailed laboratory investigations were unhelpful in diagnosis, and the patients' conditions worsened with systemic steroid therapy. Subretinal fluid was tapped and revealed acid-fast bacilli and grew Mycobacterium tuberculosis on culture. CONCLUSION: Subretinal fluid analysis can help in the detection of tuberculous granuloma and facilitate successful management.
Adult↗
Effect of beta-adrenergic agonists on paracellular width and fluid flow across outflow pathway cells.
PURPOSE: To determine whether the adrenergic agonists epinephrine and isoproterenol regulate fluid flow across endothelial cells cultured from the human aqueous outflow pathway and to evaluate associated cellular mechanisms. METHODS: Confluent monolayers of human trabecular meshwork (TM) or Schlemm's canal endothelial (SCE) cells were grown on porous filter supports. The monolayers were perfused with media while fluid flow, expressed as hydraulic conductivity (HC = microl/min/mm Hg/cm2), was continuously measured in preparations treated with isoproterenol, epinephrine, or control medium. Morphometric ultrastructural methods were used to measure the area occupied by the intercellular space and by each cell. RESULTS: SCE cells and TM cells exposed to isoproterenol or epinephrine responded with an increase in transendothelial fluid flow. Dose-response curves for both adrenergic agonists showed that HC increased linearly as a function of the log of the isoproterenol and epinephrine concentration. At 10(-4) M isoproterenol, the HC increased threefold, and threshold conditions were reached at 10(-9) M. The increase in HC was apparent after isoproterenol had been applied for 1 hour, reached a peak in 3 to 4 hours, and declined gradually to return to baseline conditions in 10 to 12 hours. Morphometric analyses showed that the area occupied by the intercellular space increased fourfold when isoproterenol was used at 10(-4) M, whereas the cell area decreased as a function of the concentration of adrenergic agonist. Epinephrine's effects on HC and cell morphology were blocked by pretreatment with equimolar concentrations of the nonselective beta-blocker, timolol. CONCLUSIONS: Epinephrine and isoproterenol increase flow through the paracellular pathway of SCE and TM cells through a beta-receptor mediated response that widens the intercellular space and reduces cell area. These findings support the hypothesis that epinephrine decreases the intraocular pressure in glaucoma therapy by promoting fluid flow across the SCE and TM cells lining tissues of the major aqueous outflow pathway.
1-Methyl-3-isobutylxanthine↗
Management of orbital lymphangioma using intralesional injection of OK-432.
AIM: To treat orbital lymphangioma with an intralesional injection of OK-432 (group A Streptococcus pyogenes of human origin). METHOD: A 14 year old boy had a right orbital cystic lymphangioma. The visual acuity in the eye was 20/28. In an initial treatment, 0.02 mg of OK-432, was injected into the tumour after aspiration of the fluid contents, but no effect was seen. The second treatment was performed with 0.04 mg of OK-432. RESULT: 4 months later, the lesion had totally shrunk to fibrous tissue. The side effects were fever, a local inflammatory reaction lasting 3 days, and increased intraocular pressure, which was managed by draining the fluid contents. Visual acuity improved to 20/15, and the visual field defect and restriction of eye movement seen before treatment disappeared. No recurrence was noted 1 year after treatment. CONCLUSION: An intralesional injection of OK-432 shrunk the lymphangioma without functional disturbance and scar in the facial skin. OK-432 may be useful for orbital lymphangioma, but further studies are still warranted to determine efficacy, complications, and the optimal dose for safe treatment.
Adolescent↗