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Results for “Intraocular fluid”

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At least 415 records · Page 23Linked to original sources

PubMed1989

Intraocular pressure after cardiopulmonary bypass surgery.

The ocular effects of cardiopulmonary bypass surgery were prospectively studied in 46 patients. We examined preoperative and post-operative visual acuity, intraocular pressure, body weight, fluids infused during surgery, hematocrit, and cardiopulmonary bypass time. On the first postoperative day mean intraocular pressure increased 2.1 mm Hg (P = .003) from baseline preoperative levels. Over the first postoperative day intraocular pressure increased in 29 (63%) of the patients. Three patients (7%) had a greater than 10 mm Hg rise. The mean intraocular pressure returned to baseline by the third postoperative day. Patient weight increased from preoperative levels an average of 9.3 lbs (P less than .0001) on day 1 and 6.5 lbs on day 3. Mean hematocrit decreased 11.3% (P less than .0001) on day 1 from baseline and remained at that level through day 3. None of the patients complained of visual dysfunction during the course of this study and none showed more than a two-line decrease in near visual acuity. The increase in intraocular pressure did not correlate with the postoperative weight gain or hemodilution. However, the medications necessary after cardiac surgery may be a significant confounding variable. This study demonstrates that one cause of ocular problems from cardiopulmonary bypass surgery may be related to the dynamics of intraocular pressure.

Adult↗

PubMed2002

Physiological importance of aquaporin water channels.

Aquaporins (AQP) are a family of at least ten homologous water transporting proteins in mammals that are expressed in many epithelial, endothelial and other tissues. Abnormalities in humans and mice lacking AQPs provide direct evidence for their physiological importance. Humans lacking AQP1 or AQP2 manifest polyuria with defective urinary concentrating ability and humans with mutations in MIP (AQP0) develop cataracts. Transgenic knockout mice lacking AQP1 or AQP3 are also remarkably polyuric, and knock-in mice expressing a mutant AQP2 have severe nephrogenic diabetes insipidus resulting in impaired neonatal survival. Other interesting phenotypes in AQP knockout mice include reduced pain sensation, reduced intraocular pressure, defective corneal fluid transport and impaired dietary fat processing (AQP1), dry skin (AQP3), protection from brain swelling and impaired hearing/vision (AQP4), and reduced fluid secretion by salivary and airway submucosal glands (AQP5). However, many phenotype studies were negative, such as normal airway/lung and skeletal muscle function despite AQP expression, indicating that tissue-specific aquaporin expression does not indicate physiological significance. The general paradigm from studies on transgenic mouse models of AQP deletion is that AQPs facilitate rapid near-isosmolar transepithelial fluid absorption / secretion, as well as rapid vectorial water movement driven by osmotic gradients. The transgenic mouse studies suggest that aquaporin inhibitors may have clinical indications as diuretics and in the treatment of cerebral edema, elevated intraocular pressure, and other conditions of abnormal fluid homeostasis.

Animals↗

PubMed2003

Dynamic morphology of clear corneal cataract incisions.

OBJECTIVE: Clear corneal cataract incisions without sutures allow for rapid visual rehabilitation after phacoemulsification but might be associated with an increased risk of postoperative infection. The goal of this study was to examine in vitro dynamic changes in unhealed clear corneal cataract incisions that might adversely affect the risk of intraocular infection. DESIGN: Laboratory investigation. METHODS: Self-sealing clear corneal incisions were created in cadaveric human and rabbit eyes, and intraocular pressure was controlled with an infusion cannula. Incisions were imaged in real time using optical coherence tomography as intraocular pressure was varied. Using an artificial anterior chamber, India ink was applied to the surface of cadaveric human corneas with clear corneal incisions to detect possible flow of surface fluid along the incision. Intraocular pressure was varied by raising and lowering the infusion bottle so as to simulate the variation in intraocular pressure that would occur with successive blinks. RESULTS: Optical coherence tomography demonstrated variation of corneal wound morphology in response to changes in intraocular pressure. Higher intraocular pressures were associated with close apposition of the wound edges, with no tendency for wound leakage. At low intraocular pressures, however, wound edges tended to gape, starting at the internal aspect of the wound. One incision opened along the entire length, allowing fluid flow across the cornea. Histologic examination revealed India ink particles in all incisions for up to three fourths of the length of the wound. CONCLUSIONS: Transient reduction of intraocular pressure might result in poor wound apposition in clear corneal incisions, with the potential for fluid flow across the cornea and into the anterior chamber, with the attendant risk of endophthalmitis.

Animals↗

PubMed2000

Detection of and discrimination between gram-positive and gram-negative bacteria in intraocular samples by using nested PCR.

A nested PCR protocol has been developed for the detection of and discrimination between 14 species of gram-positive and -negative bacteria in samples of ocular fluids. First-round PCR with pan-bacterial oligonucleotide primers, based on conserved sequences of the 16S ribosomal gene, was followed by a gram-negative-organism-specific PCR, which resulted in a single 985-bp amplification product, and a multiplex PCR which resulted in two PCR products: a 1,025 bp amplicon (all bacteria) and a 355 bp amplicon (gram-positive bacteria only). All products were detected by gel electrophoresis. The sensitivity of the assay was between 10 fg and 1 pg of bacterial DNA, depending on the species tested, equivalent to between 24 and 4 live bacteria spiked in water. The identification was complete in 3.5 h. The molecular techniques were subsequently applied to four samples of intraocular fluid, (three vitreous and one aqueous) from three patients with clinical signs of bacterial endophthalmitis (test samples) and two samples of vitreous from a patient with chronic intraocular inflammation (control samples). In all culture-positive samples (two of three vitreous and one of one aqueous), a complete concordance was observed between molecular methods and culture results. PCR correctly identified the gram stain classification of the organisms. The bacterial etiology was also identified in a culture-negative patient with clinical history and signs highly suggestive of bacterial endophthalmitis. Furthermore, control samples from a patient with chronic intraocular inflammation remained PCR negative. In summary, this protocol has demonstrated potential as a rapid diagnostic test in confirming the diagnosis of infection and also determining the Gram status of bacteria with high specificity and sensitivity.

Aqueous Humor↗

PubMed2002

Steroid-induced glaucoma after laser in situ keratomileusis associated with interface fluid.

PURPOSE: To report the ocular manifestations and clinical course of eyes developing interface fluid after laser in situ keratomileusis (LASIK) surgery from a steroid-induced rise in intraocular pressure. DESIGN: Retrospective, noncomparative interventional case series. PARTICIPANTS/INTERVENTION: We examined six eyes of four patients who had diffuse lamellar keratitis develop after uneventful myopic LASIK surgery and were treated with topical corticosteroids. PRINCIPAL OUTCOME MEASURE: Slit-lamp findings, intraocular pressure measurements, and visual field loss. RESULTS: All eyes had a pocket of fluid develop in the lamellar interface between the flap and the stromal bed associated with a corticosteroid-induced rise in intraocular pressure. However, because of the interface fluid, intraocular pressure was normal or low by central corneal Goldmann applanation tonometry in all eyes. The elevated intraocular pressure was diagnosed by peripheral measurement in several cases after months of elevated pressure. All six eyes had visual field defects develop. Three eyes of two patients had severe glaucomatous optic neuropathy and decreased visual acuity develop as a result of undiagnosed steroid-induced elevated intraocular pressure. CONCLUSIONS: A steroid-induced rise in intraocular pressure after LASIK can cause transudation of aqueous fluid across the endothelium that collects in the flap interface. The interface fluid leads to inaccurately low central applanation tonometry measurements that obscure the diagnosis of steroid-induced glaucoma. Serious visual loss may result.

Adult↗

PubMedDate not supplied

[Laser-correlation spectroscopy of the lacrimal fluid in the evaluation of the semiotic nature of postoperative inflammatory reaction and the degree of its severity in patients with diabetes mellitus after intraocular lens implantation].

Lavages of the lacrimal fluid were examined, before operation and immediately after operation, in 47 patients with diabetes mellitus and with pseudophakia in order to define the possibilities of the method of laser-correlation spectroscopy (LCS) in evaluating the semiotic nature and a severity degree of postoperative inflammation. It was found that, when the subjective symptomatology of inflammation in the LCS spectrums intensified, there was a higher contribution to the light dissemination of particles with a hydrodynamic diameter of 600 nm and more (i.e. of heavy lipoprotein complexes and of immune complexes), which were determined after a computer-based processing as a condition of primary intoxication and of immune shifts. The LCS results objectively confirmed that the degree of inflammatory changes during the early postoperative period was reliably higher in patients with a level of glycolyzed hemoglobin exceeding 9% versus patients with the above parameter being below 9%.

Diabetes Complications↗

PubMed2005

Diffusion-weighted imaging, apparent diffusion coefficients, and fluid-attenuated inversion recovery MR imaging in endophthalmitis.

We describe the appearance of endogenous bacterial endophthalmitis in a patient who underwent MR imaging of the orbits before and during the course of treatment. Intraocular hyperintensity on fluid-attenuated inversion recovery and diffusion-weighted images were found very useful for diagnosing endophthalmitis. After a few days of treatment, a marked relative increase in intraocular mean apparent diffusion coefficient values was observed, which appears to indicate good treatment response.

Anti-Bacterial Agents↗

PubMed1979

Vitrectomy techniques in retinal reattachment surgery.

Vitreous surgery techniques are useful in the management of selected retinal detachments with an otherwise poor prognosis. Vitrectomy methods can be used to remove intraocular opacities; cut vitreous sheets causing vitreo-retinal traction and separate epiretinal membranes covering or distorting the retina; provide a fluid space to aid in creation of a scleral buckle or use of an intravitreal gas bubble; perform other intraocular procedures, including transvitreal treatment of retinal breaks, transvitreal removal of subretinal fluid, and intraocular fluid-gas exchange. These surgical capabilities can be combined with conventional retinal reattachment methods to treat selected types of retinal detachment. The surgical techniques, indications for surgery, and role of vitrectomy methods in the current management of retinal detachment are reviewed.

Cryosurgery↗

PubMed1986

Treatment of intraocular lymphoma with high-dose Ara-C.

Ocular lymphoma is an uncommon clinical entity with a propensity for intracranial extension. Palliation has been reported following radiotherapy, but the ultimate prognosis is poor, and significant treatment-related morbidity is common. Recent pharmacokinetic studies have suggested that sustained therapeutic drug concentrations are achievable in cerebrospinal fluid after systemic administration of high-dose cytosine arabinoside (Ara-C). These data led the authors to attempt treatment of a case of recurrent ocular lymphoma with high-dose Ara-C. Therapeutic drug levels were documented in intraocular fluids, and prolonged objective regression of tumor was seen. Systemic high-dose Ara-C deserves consideration for the treatment of ocular lymphoma.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1999

Serologic evaluation of patients with primary and recurrent ocular toxoplasmosis for evidence of recent infection.

PURPOSE: To identify the frequency of recently acquired vs chronic systemic Toxoplasma gondii infections in patients with ocular toxoplasmosis. METHODS: Serum samples from 22 patients with primary ocular toxoplasmosis (not from scars) and 42 patients with recurrent ocular toxoplasmosis were tested for the presence of anti-T. gondii IgM, IgG, and IgA antibodies and compared with samples from 24 patients with other causes of uveitis. Intraocular production of anti-T. gondii IgG and IgA, and the presence of T. gondii DNA was determined in patient s and control subjects from whom ocular fluid was available. RESULTS: Serologic evidence of recently acquired infection was found for 11 (50%) of 22 patients with primary ocular toxoplasmosis and for one (2%) of 42 with recurrent ocular toxoplasmosis. In the uveitis control group, anti-T. gondii IgM antibodies could be detected in two (8%) of 24 patients, but anti-T. gondii IgA antibodies were not detectable. Patients with primary ocular toxoplasmosis and serologic markers of recently acquired systemic infection were significantly older than those with chronic infection (P = .008). Intraocular production of anti-T. gondii IgG was more frequently noted in patients with recurrent than primary ocular toxoplasmosis (81% vs 41%; P < .001), but intraocular T. gondii DNA was more frequently found in patients with primary ocular toxoplasmosis than in those with recurrent ocular toxoplasmosis (37% vs 4%; P < .01). CONCLUSIONS: Primary ocular toxoplasmosis can be seen in either recently acquired or chronic T. gondii infection. Patients with ocular disease and recently acquired infection were older and more likely to have T. gondii DNA in intraocular fluids.

Adolescent↗

PubMed1988

Repeated fluid-gas exchange for hypotony after vitreoretinal surgery for proliferative vitreoretinopathy.

Three patients with prolonged hypotony after vitreoretinal surgery for proliferative vitreoretinopathy were treated with repeated fluid-gas exchanges to maintain intraocular pressure and prevent the development of phthisis bulbi. We performed fluid-gas exchanges solely to treat the hypotony beyond the period when tamponade of retinal breaks was required, and without specific positioning of the bubble. In these patients, the intraocular pressure eventually returned to normal and useful vision was retained.

Adult↗

PubMed2005

Central corneal thickness and thickness of the lamina cribrosa in human eyes.

PURPOSE: Since central corneal thickness may inversely influence the amount and rate of progression of glaucomatous optic nerve damage and because lamina cribrosa thickness may be of importance in susceptibility to glaucoma, it was the purpose of the present study to evaluate whether central corneal thickness is related to lamina cribrosa thickness. METHODS: The histomorphometric study included 111 enucleated nonglaucomatous eyes of 111 white subjects. On anterior-posterior histologic sections through the pupil and the central optic disc region, the thickness of the cornea, lamina cribrosa, and peripapillary sclera and the shortest distance between the intraocular space and the cerebrospinal fluid space were measured. Axial length ranged between 20 and 32 mm. RESULTS: Mean central corneal thickness (mean +/- SD: 616.6 +/- 108.3 microm) and mean central lamina cribrosa thickness (378.1 +/- 117.8 microm) were statistically independent of each other (P = 0.15; correlation coefficient, r = 0.14). In a similar manner, lamina cribrosa thickness at the optic disc border was statistically independent of central corneal thickness (P = 0.51; r = 0.06) and peripheral corneal thickness (P = 0.34; r = 0.09). In a parallel way, peripapillary scleral thickness (P = 0.84) and the shortest distance between the prelaminar space and cerebrospinal fluid space (P = 0.10) were statistically independent of central corneal thickness. CONCLUSIONS: In nonglaucomatous human globes, central corneal thickness may not correlate significantly with lamina cribrosa thickness, peripapillary scleral thickness, and shortest distance between intraocular space and cerebrospinal fluid space. Histologic artifact and sectioning methods could partially account for the lack of an association. The study results may suggest clinically that an assumed relationship between central corneal thickness and susceptibility to glaucoma cannot be explained by an anatomic correspondence between corneal thickness and histomorphometry of the optic nerve head.

Body Weights and Measures↗

PubMed1980

Aqueous humour pralidoxime mesylate (P2S) concentrations and intraocular tension following intramuscular P2S.

Small transient increases in rabbit intraocular tension were measured following intramuscular pralidoxime mesylate (P2S) at doses of 10, 40 or 100 mg/kg. Peak increases in tension showed some dose dependency, and although not statistically correlated with plasma or aqueous humour P2S concentrations the changes in tension followed the general time-concentration profile for P2S in these fluids. P2S was not detected in aqueous humour following 10 mg/kg, but at 40 and 100 mg/kg dose dependent concentrations were detected in aqueous humour. From experiments involving multiple injections of P2S there was no evidence for a cumulative effect of P2S on the eye. The results indicate that P2S can enter aqueous humour following its parenteral administration and is associated with changes in intraocular fluid dynamics. Whilst they also suggest that some ophthalmic side-effects of oxime therapy may be a consequence of a direct action of the oxime on the eye, they do not exclude contributions from actions at other sites.

Animals↗

PubMed2003

Spontaneous retinal venous pulsation: aetiology and significance.

Spontaneous retinal venous pulsation is seen as a subtle variation in the calibre of the retinal vein(s) as they cross the optic disc. The physical principles behind the venous pulsations has been the point of much debate. Initial theories suggested that the pulsation occurred because of the rise in intraocular pressure in the eye with the pulse pressure. This article presents an argument that this is not the case. The pulsations are in fact caused by variation in the pressure gradient along the retinal vein as it traverses the lamina cribrosa. The pressure gradient varies because of the difference in the pulse pressure between the intraocular space and the cerebrospinal fluid. The importance of this is that as the intracranial pressure rises the intracranial pulse pressure rises to equal the intraocular pulse pressure and the spontaneous venous pulsations cease. Thus it is shown that cessation of the spontaneous venous pulsation is a sensitive marker of raised intracranial pressure. The article discusses the specificity of the absence of spontaneous venous pulsation and describes how the patient should be examined to best elicit this important sign.

Blood Pressure↗

PubMedDate not supplied

Interface fluid and diffuse corneal edema after laser in situ keratomileusis.

PURPOSE: To report a new complication of interface fluid accumulation and corneal edema in an uneventful laser in situ keratomileusis (LASIK) procedure. METHODS: Uncomplicated bilateral LASIK for myopia using the Hansatome microkeratome was performed. One day postoperatively, the patient noted decreased visual acuity. The topical corticosteroid was changed from dexamethasone to prednisolone acetate 1% every 2 hours. Two weeks later the patient reported worsening visual acuity in both eyes. Uncorrected visual acuity was 20/200 in the right eye and 20/100 in the left. Slit-lamp biomicroscopy indicated significant fluid build-up in the interface. Intraocular pressure (IOP) by Goldmann applanation tonometry was 15 mmHg in the right eye and 14 mmHg in the left. RESULTS: After 4 weeks, intraocular pressure by bidigital pressure was increased and high. The corticosteroid was discontinued and antiglaucoma medication lowered the intraocular pressure, which resulted in corneal clearing and disappearence of interface fluid in both eyes. CONCLUSIONS: Early recognition of this new complication of LASIK is necessary. The falsely low reading of IOP in the setting of interface fluid was the result of easy compressibility of the fluid-filled space and reflects the pressure of the interface fluid. This apparently low IOP reading can be an additional sign of the existence of interface fluid. The corticosteroid should be discontinued and antiglaucoma medication instituted. This should lead to a lowering of intraocular pressure and result in corneal clearing and disappearence of the interface fluid with improvement in visual acuity.

Adult↗

PubMed2004

New dendritic adhesives for sutureless ophthalmic surgical procedures: in vitro studies of corneal laceration repair.

OBJECTIVE: To compare a biodendrimer adhesive with a conventional suture for repairing linear and stellate corneal lacerations. METHODS: A keratome knife was used to create 4.1-mm full-thickness linear incisions (n = 36) and 3 x 4-mm full-thickness stellate incisions (n = 25) in the central cornea of enucleated human eyes. The incisions were sealed with either a suture or the biodendrimer adhesive. The globes were inflated with balanced salt solution, and the increase in intraocular pressure was monitored via a cardiac transducer until fluid leaked from each eye. This intraocular pressure reading from the transducer was recorded at the sight of any leakage through the wound (leakage pressure). By using the Wilcoxon rank sum test, the median leakage pressure was compared for each closure method, separately for each wound group. By using the 1-sided 1-sample t test, each mean leakage pressure value was compared with 34 mm Hg, which is the intraocular pressure under certain stressful physiologic conditions (eg, coughing and the Valsalva maneuver). RESULTS: For globes that underwent a linear incision, the mean leakage pressure was 78.7 mm Hg for the sutured group and 109.6 mm Hg for the adhesive group. Globes that underwent a stellate incision had a mean leakage pressure of 57.8 mm Hg for the sutured group and 78.7 mm Hg for the adhesive group. All of these pressures showed a statistical significance from 34 mm Hg via a 1-sided 1-sample t test. CONCLUSIONS: The difference in leakage pressures for all 4 groups was statistically significant relative to 34 mm Hg. This suggests that either method of closure, adhesive or suture, can withstand physiologic increases in intraocular pressure postoperatively and that biodendrimer adhesives are able to seal large corneal lacerations.Clinical Relevance The use of biodendrimer adhesives to repair a corneal wound constitutes a viable alternative clinical procedure to conventional sutures.

Biocompatible Materials↗

PubMed1993

Carbonic anhydrase inhibitory activity and ocular pharmacology of organic sulfamates.

Organic sulfamates are a new variation to the carbonic anhydrase (CA) inhibitor structure-action relationship. Inhibitory activity is conferred by the classic sulfonamide group, but through linkage to the benzene ring by an oxygen. AHR-16329, a representative sulfamate, has an acidic (sulfonamide, pKa 8.9) and basic (imidazole, pKa 6.0) group and has desirable physicochemical properties for topical intraocular pressure lowering: good water solubility below pH 6.0, a CHCl3/buffer ratio of 0.5 at pH 7.0 and a Kl against CA-II of 7 nM. Inhibition of CO2 hydration is noncompetitive. When applied locally to the eye, AHR-16329 reaches significant levels in ocular tissues and fluids and reduces significantly intraocular pressure. Five percent concentration gives the greatest reduction, equivalent to systemic inhibitors; 2 and 5% have similar pressure x time duration. These studies expand structure-action relations in the field of CA inhibitors and the validity of developing topical CA inhibitors for treatment of glaucoma.

Animals↗

PubMed1979

Vitrectomy instrumentation for surgical evacuation of total anterior chamber hyphema and control of recurrent anterior chamber hemorrhage.

A patient with recurrent bleeding during hyphema extraction with the O'Malley ocutome was treated by elevation of the intraocular pressure to 50 mm Hg for 5 minutes with fluid from the infusing needle. When intraocular pressure was returned to normal, there was cessation of bleeding and postoperatively the anterior chamber remained free of blood. Elevation of intraocular pressure is offered as an initial alternative to air injection or cyclodiathermy for control of bleeding during hyphema extraction.

Child↗