PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Intraocular fluid”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,009 records · Page 56Linked to original sources
PubMed2003

Role of aquaporin water channels in eye function.

The aquaporins (AQPs) are a family of more than 10 homologous water transporting proteins expressed in many mammalian epithelia and endothelia. At least five AQPs are expressed in the eye: AQP0 (MIP) in lens fiber, AQP1 in cornea endothelium, ciliary and lens epithelia and trabecular meshwork, AQP3 in conjunctiva, AQP4 in ciliary epithelium and retinal Müller cells, and AQP5 in corneal and lacrimal gland epithelia. This cell-specific expression pattern suggests involvement of AQPs in corneal and lens transparency, intraocular pressure (IOP) regulation, retinal signal transduction, and tear secretion. Indeed, humans with mutant AQP0 develop cataracts. Mice lacking AQP1 have reduced IOP and impaired corneal transparency after swelling, and mice lacking AQP4 have reduced light-evoked potentials by electroretinography. There is evidence for impaired cellular processing of AQP5 in lacrimal glands of humans with Sjogren's syndrome. AQPs facilitate fluid secretion and absorption in the eye, and hence are involved in the regulation of pressure, volume and tissue hydration. Pharmacological alteration of AQP function may provide a new approach for therapy of glaucoma, corneal edema, and other diseases of the eye associated with abnormalities in IOP or tissue hydration.

Animals↗
PubMed1999

Pars plana vitrectomy without scleral buckle for pseudophakic retinal detachments.

OBJECTIVE: To report the anatomic and visual results of primary pars plana vitrectomy (PPV) without scleral buckling to repair primary rhegmatogenous retinal detachments in pseudophakic eyes. DESIGN: Nonrandomized, prospective, comparative clinical trial. PARTICIPANTS: Two hundred eighty-three consecutive patients (294 eyes) with pseudophakia, peripheral retinal tears, and new rhegmatogenous retinal detachments were treated according to the surgery protocol. INTERVENTION: Patients underwent PPV with fluid-gas exchange and endolaser to repair the retinal detachment. Two hundred sixty-four patients (275 eyes) were followed from 6 months to 6 years and 8 months with an average follow-up of 19 months. MAIN OUTCOME MEASURES: Reattachment of the retina and visual outcome were compared to previously published studies. RESULTS: Of 97 eyes with a macula-attached rhegmatogenous retinal detachment, 88 eyes (91%) were reattached with a single operation, and of the 178 eyes with a macula-detached retinal detachment, 153 (86%) eyes were reattached with a single operation. In 241 (88%) of 275 eyes, the retina was reattached with a single operation, and in 265 (96%) of 275 eyes, the retina was ultimately reattached with subsequent operations. The median initial visual acuity was 20/300, and the median final visual acuity was 20/40. The rate of reattachment with one operation was similar for eyes with an anterior chamber intraocular lens (91%) and for eyes with a posterior chamber intraocular lens (88%). Refractive error measurements obtained in 81 eyes were essentially unchanged. The mean change in refractive error was -0.15 diopter. Seventeen eyes (6%) developed macular puckers requiring surgery, 46 eyes (17%) developed cystoid macular edema, and 6 eyes (2%) developed full-thickness macular holes. CONCLUSION: Primary PPV with fluid-gas exchange and laser is a safe, effective method to repair primary pseudophakic retinal detachments. The anatomic reattachment rate and the visual acuity obtained with this technique appear to be at least as good as those reported in the literature for scleral buckling, PPV with scleral buckling, and pneumatic retinopexy.

Fluorocarbons↗
PubMed1983

Subretinal neovascularization in the Vogt-Koyanagi-Harada syndrome.

Two Hispanic patients with Vogt-Koyanagi-Harada (VKH) syndrome each developed a disciform lesion involving the macula of one eye several months after the onset of symptoms. Each had extraocular manifestations which included pleocytosis of the cerebrospinal fluid. The disciform lesions were associated with retinochoroidal anastomoses, a finding not previously reported in VKH syndrome. Each patient had a separate extramacular disciform lesion in the same eye. Two other Hispanic patients with diffuse bilateral intraocular inflammation had ocular findings consistent with VKH syndrome. One of these patients developed bilateral peripapillary disciform lesions and the other developed a disciform macular scar in one eye. Fluorescein angiography in each patient showed early irregular hyperfluorescence with late intense staining. The disciform detachments occurred in areas of reactive proliferation of the retinal pigment epithelium, and we postulate that growth of subretinal new vessels occurred through areas of Bruch's membrane that were damaged by the inflammation.

Adolescent↗
PubMedDate not supplied

Studies on the adrenergic systems of the eye at the Wilmer Institute.

The study of the ocular adrenergic systems at the Wilmer Institute over the last 40 years began with the examination of the formation and outflow of aqueous humor by Jonas Friedenwald and his co-workers in the early 1940's. At that time, researchers were attempting to understand the mechanisms of fluid dynamics in the eye, with the idea of altering these mechanisms to alleviate glaucoma only a distant goal. In the late 1950's, Langham and others reported on the effect of superior cervical ganglionectomy on intraocular pressure, following this work with a succession of papers on the relationship between alpha and beta adrenergic substances and aqueous humor dynamics. Sears, in collaboration with Bárány, described the effects of alpha and beta adrenergic substances on outflow resistance. Eakins, in 1963, suggested a mechanism of action for isoproterenol in the lowering of intraocular pressure. Work on timolol at Wilmer began with a report from Radius, Diamond, Pollack and Langham covering experimental studies with rabbits and clinical studies of the drug's ocular hypotensive effects on glaucoma patients. Richter and others also studied a small number of patients on maximal therapy and found further intraocular pressure reduction with added timolol.

Academies and Institutes↗
PubMed2001

Modulation of aqueous humor outflow facility by the Rho kinase-specific inhibitor Y-27632.

PURPOSE: The goal of this study was to investigate the role of Rho kinase in the modulation of aqueous humor outflow facility. Rho kinase, a critical downstream effector of Rho GTPase is recognized to control the formation of actin stress fibers, focal adhesions, and cellular contraction. METHODS: Expression of Rho GTPase, Rho kinase, and other downstream targets of Rho GTPase were determined in human trabecular meshwork (HTM) and Schlemm's canal (SC) primary cell cultures by Western blot analysis. The Rho kinase-specific inhibitor (Y-27632)-induced changes in actin stress fibers, focal adhesions, and protein phosphotyrosine status were evaluated by staining with rhodamine-phalloidin, anti-paxillin, and anti-phosphotyrosine antibodies, respectively. Myosin light-chain phosphorylation was determined by Western blot analysis. Y-27632-induced changes in SC cell monolayer permeability were quantitated using a colorimetric assay to evaluate horseradish peroxidase diffusion through SC cell monolayers grown in transwell chambers. Aqueous humor outflow facility was measured using enucleated porcine eyes and a constant-pressure perfusion system. RESULTS: Treatment of HTM and SC cells with Y-27632 (10 microM) led to significant but reversible changes in cell shape and decreases in actin stress fibers, focal adhesions, and protein phosphotyrosine staining. SC cell monolayer permeability increased (by 80%) in response to Y-27632 (10 microM) treatment, whereas myosin light-chain phosphorylation was decreased in both HTM and SC cells. Aqueous humor outflow facility increased (40%-80%) in enucleated porcine eyes perfused with Y-27632 (10-100 microM), and this effect was associated with widening of the extracellular spaces, particularly the optically empty area of the juxtacanalicular tissue (JCT). The integrity of inner wall of aqueous plexi, however, was observed to be intact. CONCLUSIONS: Based on the Rho kinase inhibitor-induced changes in myosin light-chain phosphorylation and actomyosin organization, it is reasonable to conclude that cellular relaxation and loss of cell-substratum adhesions in HTM and SC cells could result in either increased paracellular fluid flow across Schlemm's canal or altered flow pathway through the JCT, thereby lowering resistance to outflow. This study also suggests Rho kinase as a potential therapeutic target for the development of drugs to modulate intraocular pressure in glaucoma patients.

Actins↗
PubMed1997

Ocular-specific chemical delivery systems of betaxolol for safe local treatment of glaucoma.

Novel ketomethoxime (BMO) and oxime (BO) analogs of betaxolol (B) were prepared through the oxidation of betaxolol, followed by quenching of the ketone with the appropriate oxyamine. The Z isomers were kinetically favored and thermodynamically more stable. Isomerization to reach an equilibrium mixture of Z/E was observed for all pure isomers in buffers. Equilibration is much faster, however in biological fluids. Ocular administration of any of the oxime derivatives, delivers betaxolol specifically to the eye tissues, with the highest concentration in the iris ciliary body. Both BMO and BO, when applied topically, showed marked reduction of intraocular pressure (IOP) in normotensive rabbits. No effect on isoproterenol-induced tachycardia in rabbits and rats were observed, even after iv. administration. Very mild eye irritation, which was less than that of betaxolol hydrochloride, was observed particularly with BMO maleate, which is an excellent candidate for safe treatment of glaucoma.

Administration, Topical↗
PubMed2003

Penetration of oral and topical ciprofloxacin into the aqueous humour.

AIMS: To investigate the penetration of ciprofloxacin via different modes of administration into the aqueous humour using capillary zone electrophoresis and to determine its prophylactic role in ophthalmic surgery. METHODS: A prospective study was conducted of 84 patients, divided into two groups, undergoing routine cataract surgery and intraocular lens implantation. Forty patients received 750 mg ciprofloxacin orally the evening before and on the morning of surgery 12 h apart. Forty-four patients received one drop of 0.3% topical ciprofloxacin 90 and 30 min prior to surgery. At the commencement of surgery 0.1-0.2 mL of aqueous fluid was sampled from the anterior chamber and assayed for ciprofloxacin concentration using capillary-zone electrophoresis. RESULTS: The concentration of ciprofloxacin in the group receiving topical doses was less than 0.1 micro g/mL, which is well below the minimum inhibitory concentration for cipro-floxacin inhibiting 90% (MIC90) of strains of Staphylococcus epidermidis (0.4 micro g/mL). The mean concentration of ciprofloxacin in the aqueous humour of the oral group was 0.26 micro g/mL with a standard deviation of 0.12 micro g/mL (range 0.09-0.67 micro g/mL) with only 12.5% achieving levels higher than MIC90 for S. epidermidis. CONCLUSION: The topical ciprofloxacin 0.3% as given in this study achieved poor aqueous humour concentration. Oral ciprofloxacin given in this regime should not on its own be considered adequate prophylaxis in intraocular surgery. Capillary zone electrophoresis can be used as an alternative tool to the existing high-pressure liquid chromatography methods for analysing ciprofloxacin level in the aqueous humour.

Administration, Oral↗
PubMed2006

[Effect of timolol on central corneal thickness and endothelial cell density].

BACKGROUND: The measurement of corneal thickness plays an increasing role in glaucoma screening and diagnosis. The influence of a variety of drugs on corneal thickness is well established. Especially for antiglaucomateous drugs this effect seems to be important. However, little is known about the influence of beta receptor antagonists on corneal thickness. The aim of this study was to provide evidence of the effect of timolol on central corneal thickness and endothelial cell density. MATERIALS AND METHODS: Ten healthy volunteers (five women and five men) with a mean age of 29 years (range 25 to 56 years) were examined in a double-blind, prospective and randomised pilot study. Intraocular pressure, corneal thickness and endothelial cell density was estimated before as well as fifteen minutes, 24, 48, 72 and 96 hours after application of timolol 0.5 % eye drops twice daily. The partner eye received sodium hyaluronate eye drops twice daily and served as a control. RESULTS: The application of timolol showed a decrease of intraocular pressure from initially 12 mmHg to 9 mmHg after four days (p = 0,0188) as well as an increase of corneal thickness from 537 microm to 557 microm after four days (p = 0,0659). There was no change of intraocular pressure (p = 0,9935) or corneal thickness (p = 0,9998) in the control eyes. There was also no effect of timolol (p = 0,2782) or sodium hyaluronate (p = 0,1940) on endothelial cell density. CONCLUSIONS: The study provides evidence of the influence of beta receptor antagonists on corneal thickness. This effect may be caused by receptor mediated influences on corneal ion and fluid transport. Further studies are needed to show if the increase of corneal thickness after application of topical timolol has clinical importance.

Adult↗
PubMed1984

Giant papillary conjunctivitis in connection with corneoscleral supramid (nylon) suture knots.

A material consisting of 27 patients had corneoscleral wound closure by 8-0 polyamide (supramid, nylon) sutures after intracapsular cataract extraction and intraocular lens implantation. A few months after surgery 16 patients had developed giant papillary conjunctivitis of the upper tarsus of the operated eye, associated with itching and blurring. The earlier stages of the condition, as described by other authors, could be defined in the remaining 11 patients. Cytologic tests - pipette samples of tear fluid and tarsal conjunctival scrapings - demonstrated eosinophil leucocytes and neutrophilia in most of the giant papillary conjunctivitis cases. The conjunctival scraping proved the more sensitive test for detection of eosinophils, the pipette test being mainly an indicator of inflammatory reaction. The condition seems to be allergic with an element of mechanical irritation. The use of polyamide sutures of the 8-0 size is not recommended.

Aged↗
PubMed1998

Short-term comparative study of topical 2% carteolol with and without benzalkonium chloride in healthy volunteers.

AIM: A crossover, randomised double blind study was undertaken in 30 healthy volunteers, in order to compare the tolerance of 2% carteolol with and without preservative in short term use. METHODS: Complete ophthalmic examinations were performed before and 30, 60, and 180 minutes after instillation of one drop of the solution, and after 3 days of preservative treatment. After a 5 day washout, the same examinations were done with the second drug. RESULTS: Results showed good general tolerance for both formulations. No significant difference in subjective tolerance, corneal aesthesiometry, punctuate keratitis, Schirmer's test, intraocular pressure (IOP) decrease (about 25% in the two groups at 3 hours, 10% after 3 days of treatment), resting cardiac frequency, or blood pressure was observed. However, break up time was significantly reduced from baseline by preserved carteolol both at 3 hours (10.40 (5.9) seconds to 6.15 (3.9) seconds, p = 0.001) and after 3 days (7.72 (5.5) seconds, p = 0.04). Preservative free carteolol did not significantly change the break up time (baseline 9.08 (5.7) seconds; 3 hours = 7.88 (5.5) seconds, not significant; day 3 = 8.35 (5.8), non-significant). CONCLUSIONS: These results confirm that carteolol is well tolerated, either with or without preservative. The preservative free group showed better stability of the tear film, without loss of effect on IOP. This difference, although mild in the healthy young subjects in the present study could be much more relevant in those patients treated long term, older patients, and/or those suffering from ocular surface disorders. In such instances, preservative free drugs could be of potential benefit to protect the lacrimal fluid integrity and corneoconjunctival surface.

Administration, Topical↗
PubMed1984

A method for near-continuous determination of aqueous humor flow; effects of anaesthetics, temperature and indomethacin.

A method is described for near-continuous determination of aqueous humor flow. The anterior chamber is perfused with push-pull coupled syringes at a low rate with a fluid containing labelled albumin. An external circuit is used to determine continuously the anterior chamber concentration of the labelled protein. The dilution data are analysed on-line by a minicomputer which permits rapid calculation of the anterior chamber volume and the rate of flow of aqueous humor. The technique and some experiments of technical interest are reported. Experiments in monkeys with different anaesthetics resulted in flow values of 0.99 +/- 0.02, 1.47 +/- 0.09 and 0.99 +/- 0.04 microliter min-1 for pentobarbital, urethane and ketamine anaesthesia, respectively. By using 125I-labelled albumin in one eye and 131I-labelled albumin in the other, it was possible to determine flow in both eyes. Highly significant correlation coefficients between the two sides were found for the rate of aqueous flow, intraocular pressure and anterior chamber volume. Rapid changes in inflow into the anterior chamber from the posterior chamber were produced by elevating and then lowering the intraocular pressure; the delay inherent in the method was about 6 min. Indomethacin, 3 mg kg-1 body wt., had no effect on aqueous humor flow in eyes cannulated with a minimum of trauma. In eyes with problematic cannulation indomethacin at this dose tended to delay an irritation response. Changes in temperature of the fluid perfused through the anterior chamber had no clear effect on the rate of aqueous flow. Warming the animals about 3-4 degrees C above the normal temperature tended to increase the rate of aqueous flow. Cooling by 3-4 degrees C had no clear effect. Cooling after an initial warming also had no clear effect. The rate of flow of aqueous humor from the anterior chamber to the general circulation was calculated from data for the accumulation of labelled albumin in the general circulation. The difference between the rate of aqueous flow determined from the dilution data and the flow into blood was assumed to represent uveoscleral flow. In 14 animals with an aqueous flow of 1.19 +/- 0.08 microliters min-1 the flow to the general circulation was 0.57 +/- 0.055 and uveoscleral flow 0.61 +/- 0.09 microliters min-1. The procedure and mathematical treatment will be applicable to flow determinations with other large molecules and in other systems.

Anesthetics↗
PubMed1998

[Capsular bag distension syndrome after capsulorhexis].

We present one case of capsular bag distension associated with lens phacoemulsification, capsulorhexis and posterior chamber intraocular lens (IOL) insertion. Capsular bag distension is a rare postoperative complication of continuous tear anterior capsulotomy and presents the following characteristics: (1) postoperative myopic over-refraction; (2) shallowing of the anterior chamber associated with anterior shift of the IOL and the iris diaphragm; (3) important posterior distension of the posterior capsule and (4) sealing of the capsule to the anterior surface of the IOL. In our case, recovery of vision was incomplete after cataract surgery although the procedure was uneventful and no other ocular pathology was found. A neodymium: YAG laser anterior capsulotomy peripheral to the edge of the IOL remedied the situation allowing the capsular fluid to regress into the anterior chamber and the IOL to return in a normal posterior position.

Aged↗
PubMed1993

Aqueous humor flow and flare in patients with myotonic dystrophy.

PURPOSE: Myotonic dystrophy is an autosomal dominant form of muscular dystrophy associated with a mutation that affects a gene on chromosome 19. Extremely low intraocular pressure is one of a constellation of clinical signs that sometimes accompany this disorder. This study was performed to determine if the ocular hypotony can be explained by aqueous humor hyposecretion. METHODS: Seventeen persons with myotonic dystrophy and seventeen age-matched controls were studied. Intraocular pressure, light scattering (flare), fluorescein clearance at various times of day, and the response of the eye to the topical timolol were measured. RESULTS: Intraocular pressure was 40% lower in the persons with myotonic dystrophy (8.4 mm Hg vs 14.0 mm Hg) and flare was 50% higher (55.8 mg/dl albumin equivalent vs 37.1 mg/dl albumin equivalent). Fluorescein clearance in persons with myotonic dystrophy was indistinguishable from normal at all times of day. Myotonic eyes responded normally to topical timolol. The physiological data of this study are most consistent with the conclusion that the rate of aqueous humor flow is reduced approximately 9%, and the rate of inward leakage of light scattering proteins is increased approximately 37% in well-established myotonic dystrophy with ocular hypotony. CONCLUSIONS: The reduced aqueous humor flow alone is insufficient to explain the ocular hypotony. We hypothesize that the hypotony is due primarily to atrophy of the ciliary muscle that increases fluid exchange between the anterior chamber and the anterior uvea with consequent enhancement of uveoscleral outflow.

Administration, Topical↗
PubMed1997

Annular peripheral choroidal detachment simulating aqueous misdirection after glaucoma surgery.

PURPOSE: The purpose of the study was to define a newly recognized complication after glaucoma surgery and to recommend a therapeutic regimen. METHODS: Eighteen patients diagnosed initially as having aqueous misdirection after glaucoma surgery, but who subsequently were found by ultrasonography to have an annular peripheral choroidal detachment that resulted in secondary angle closure glaucoma, were studied. Ten of these patients were treated with topical cycloplegics and corticosteroids, and 8 were treated with drainage of suprachoroidal fluid. Outcomes of these two treatment methods were compared. RESULTS: Annular peripheral choroidal detachment reliably was diagnosed with ultrasonography. Of the variables studied, time elapsed before resolution of the annular peripheral choroidal detachment was noted to be statistically significant (P < 0.00005). Immediate resolution followed drainage of suprachoroidal fluid, whereas a mean of 19.6 days was required for resolution after medical therapy. CONCLUSIONS: Annular peripheral choroidal detachment should be considered in the differential diagnosis of a flat or shallow anterior chamber with normal or high intraocular pressure after glaucoma surgery. The diagnosis of annular peripheral choroidal detachment can be confirmed most reliably by ultrasonography. Medical therapy is as effective as is surgery, although a significantly longer time to resolution is required.

Adult↗
PubMed1983

Mathematical modelling of aqueous humour outflow from the eye through the pores in the lining endothelium of Schlemm's canal.

Aqueous humour leaves the eye mainly by way of pore openings in vacuolar swellings in the endothelial cells which line the wall of Schlemm's canal. Calculation of the resistance to fluid flow offered by these small pores requires data on their incidence and dimensions linked to a suitable mathematical model. Data are derived from scanning electron microscopy (SEM) studies conducted on rhesus monkey eyes maintained at an intraocular pressure (IOP) of either 8 or 15 mmHg and on human eyes either untreated controls or treated with pilocarpine. Mathematical models of flow through the pore openings are developed. Application of a Venturi tube model to the SEM data shows that the pore resistance of rhesus monkey eyes at 8 mmHg was seventeen times greater than that at 15 mmHg while the pore resistance in untreated human eyes was five times greater than in eyes which received pilocarpine.

Animals↗
PubMed1981

Diagnostic vitrectomy.

The histopathologic and cytopathologic study of ocular fluids obtained for diagnostic purposes is presented. The analysis of fluid specimens with millipore filter, celloidin bag-cell block, and transmission electron microscopy techniques has proved to be effective for establishing and confirming clinical diagnoses. Diagnostic vitrectomy can be readily used to evaluate such conditions as intraocular tumors, lens and blood-induced glaucoma, inflammatory conditions, amyloidosis, persistent hyperplastic primary vitreous (PHPV), epithelial ingrowth, and tractional vitreoretinal membranes.

Adult↗