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At least 253 records · Page 14Linked to original sources

PubMed1987

Intraoperative use of pure perfluoropropane gas in the management of proliferative vitreoretinopathy.

A single-step technique for fluid-gas exchange with pure perfluoropropane gas in proliferative vitreoretinopathy (PVR) is described. The technique was used in 38 eyes of 38 patients. Permanent and total retinal reattachment, with a minimum follow-up of 6 months after gas disappearance, was achieved in 24 eyes (63%). The anatomical success rate was 80.9% (17/21 eyes) in PVR grade C and 41% (7/17 eyes) in PVR grade D. Twenty-two of the successful eyes (92%) underwent a single operation. Thirteen of the successful eyes (54%) obtained final visual acuities of 0.1 or better. Severe increase of intraocular pressure postoperatively, due to overestimation of the intraocular space available for gas expansion, is a potential risk of the technique. This risk should be avoided by means of preoperative evaluation of the vitreous cavity volume with A-scan ultrasonography and intraoperative measurement of the intraocular fluid volume displaced by scleral buckling.

Eye Diseases↗

PubMed1996

Multiple recurrent branch retinal artery occlusions associated with varicella zoster virus.

PURPOSE: The authors describe an immunocompetent patient who developed multiple recurrent branch retinal artery occlusions (BRAOs) associated with the varicella zoster virus (VZV). METHODS: A 69-year-old woman with mild bilateral vitritis developed superior and inferior BRAOs in her right eye with decreased visual acuity to 20/40, and a peripheral BRAO inferotemporally in her left eye. One month later, the inferotemporal BRAO progressed proximally in her left eye with a decrease of visual acuity to 20/40. After an extensive negative systemic evaluation, she underwent a diagnostic pars plana vitrectomy of her right eye. RESULTS: Vitreous fluid was positive for VZV DNA by polymerase chain reaction (PCR). The patient was treated with intravenous acyclovir and systemic oral steroids. After remaining disease free for 3 months, the patient had two recurrences: 1) a mild vitritis and 2) development of a new superior temporal artery occlusion in the left eye. Both recurrences were treated with oral acyclovir and systemic steroids. The patient remained recurrence free for 12 months on a maintenance dose of oral acyclovir, and for 4 additional months without acyclovir. CONCLUSIONS: Varicella zoster virus can be associated with the syndrome of multiple recurrent BRAOs. The diagnosis of VZV-associated BRAO can be established by PCR of intraocular fluid.

Acyclovir↗

PubMed2006

Oxygen distribution in the rabbit eye and oxygen consumption by the lens.

PURPOSE: Excessive exposure to oxygen has been proposed to be a risk factor for nuclear cataracts. For a better understanding of the metabolism of oxygen in the eye, oxygen distribution was mapped in the intraocular fluids, and the rate of oxygen consumption by the lens in rabbits breathing different levels of oxygen was calculated. METHODS: Young albino rabbits were anesthetized, intubated, and exposed to normoxic, hypoxic, or hyperoxic conditions. The hemoglobin saturation of the blood was monitored with a pulse oximeter, and arterial oxygen levels were measured with a blood gas analyzer. A fiberoptic optical oxygen sensor (optode) was used to determine oxygen levels in different regions of the eye. Oxygen flux across the posterior of the lens was calculated from the measured oxygen gradients in the vitreous chamber. RESULTS: Oxygen levels in the ocular fluids changed markedly when rabbits breathed air made hypoxic or hyperoxic. Oxygen levels were highest near the retinal vasculature, the iris vasculature, and the inner surface of the central cornea. Compared with nearby regions, oxygen levels were decreased in the aqueous humor closest to the pars plicata of the ciliary body and near the anterior chamber angle. Oxygen levels were generally lower closer to the lens. From the oxygen gradients in the vitreous body, oxygen consumption by the posterior half of the lens was calculated to be 0.2 to 0.4 microL/h under normoxic conditions. Oxygen consumption by the posterior of the lens increased in proportion to the amount of oxygen supplied. CONCLUSIONS: Intraocular oxygen is mostly derived from the retinal and iris vasculature and by diffusion across the cornea. Freshly secreted aqueous humor and the aqueous humor in the anterior chamber angle are relatively depleted of oxygen. The marked increase in oxygen consumption that occurs when the lens is exposed to increased oxygen is likely to result in the production of higher levels of reactive oxygen species and may provide a link between elevated oxygen levels and the risk of nuclear cataracts.

Animals↗

PubMedDate not supplied

[Clinical aspects of normal pressure glaucoma].

A comprehensive ophthalmologic examination of 45 patients (76 eyes) with normal pressure glaucoma (confirmed in hospital by using tonography, computer perimetry with the "Humphrey-720" field analyzer being applied and by photometry of the optic nerve disk with the "Nidec" fundus-chamber being applied) was carried out. Polymorphism of clinical manifestations of the disease and specific features of such manifestations with regard for an initial level of the ophthalmic tone were revealed. Elderly age, the condition of the anterior segment and hydrodynamic parameters close to the age norm, a pronounced saucer-shaped or asymmetric excavation and segment-type nature of visual field defects were found to be more typical for glaucomatous patients with a relatively low intraocular pressure--IOP (< or = 20 mm Hg according to Maklakov). Younger age, dystrophic changes in the iris and drainage zone similar to those occurring at typical primary open-angle glaucoma, low indices of secretion combined with low indices of intraocular fluid discharge, predominant symmetric excavation and diffuse reduction of light sensitivity along the periphery with a predominant damage of the nasal segments were found to be more typical for glaucomatous patients with relatively high IOP (< or = 26 mm Hg). The described clinical aspects enable a timely diagnosis of the disease and an adequate choice of treatment.

Adult↗

PubMed1984

Ocular effect of neodymium-YAG laser.

We aimed a high-powered pulsed neodymium-YAG laser incrementally from air to the anterior portion of the vitreous in rabbits to evaluate its effect on the corneal endothelium, the lens, and the dynamics of intraocular fluid. Corneal endothelium damage occurred as much as 3.5 mm away from the site of optical breakdown. The degree of tissue damage was inversely proportional to the distance from the site of optical breakdown, and the damage pattern at a given distance was the same whether the optical breakdown was anterior or posterior to the corneal endothelium. A single 4-mJ shot (mode-locked train) of laser light causes disintegration and liquefaction of the lens in a spherical area 300 micron in diameter. The damage extends posteriorly to a distance of 450 micron. The effect of this explosion denatures the surrounding cortical fibers for an area of 50 to 80 micron. Increased intraocular pressure was noted in all instances of anterior or posterior capsulotomy, probably as a result of the release of liquefied cortical material and mechanical obstruction of the chamber angle. No increase in intraocular pressure occurred when the lens capsule remained intact.

Animals↗

PubMedDate not supplied

[Sinusotrabeculectomy with regulated filtration in the treatment of secondary glaucoma].

A new method for surgical treatment of secondary glaucoma (neovascular, postuveal, traumatic, and aphakic) is described. The aims of the new method are as follows: regulation of ophthalmic tone in the postoperative period, pain relief, organ preservation, stabilization of the process, and creation of reliable routes of intraocular fluid discharge with formation of a stable diffuse functional pad. Seven patients (8 eyes) aged 13-70 years were operated on and followed up for up to 6 months. Preliminary results are presented. Positive shifts were observed in all cases.

Adolescent↗

PubMed1989

[Surgical results of dissection of the superficial temporal artery in patients with preglaucoma and initial open-angle glaucoma].

Results of superficial temporal artery dissection performed in 42 patients (44 eyes) with preglaucoma and initial open-angle glaucoma have shown no impairement of visual field, visual acuity, optic disc in the period from 0.5 to 1.5 years after it. The increased linear rate of bloodflow after the operation remained stable in 17 eyes of patients with preglaucoma and in 14 eyes of patients with glaucoma. Intraocular pressure became normalized in 20 and 19 eyes as well as intraocular fluid outflow in 14 and 13 eyes, respectively. In both groups there was a tendency to normalization of retinal functions and hydrodynamics of the eye. Thus, the operation produces improvement of regional bloodflow, tonographic and electrophysiologic indices. Its usage is considered to be reasonable, but, when determining indications to it, an individual approach is necessary.

Follow-Up Studies↗

PubMed1954

Diagnosis and treatment of glaucoma; a review of recent developments.

Tonography is helpful in the diagnosis of doubtful cases of chronic simple glaucoma. If also gives a good indication of the status of the disease in a given eye. The most useful miotic in the treatment of glaucoma is still pilocarpine. Carbachol is more potent but must be used in an anhydrous base ointment or in a solution of a wetting agent. DFP (diisopropyl fluorophosphate) produces undesirable side effects because of the hyperreactivity of the ciliary body and iris sphincter which it causes. These can be partly overcome by using pilocarpine first. Diamox is a carbonic anhydrase inhibitor that is effective when given orally. In many cases it produces at least a temporary lowering of tension in glaucomatous eyes, apparently by reducing the secretion of intraocular fluid. Its ultimate value in glaucoma remains to be seen. The cyclodiathermy operation which has been modified somewhat by Weekers has had a recent increase in use but the long-term results have been somewhat disappointing. The importance of early operation in narrow angle glaucoma is becoming more and more apparent. Following iridectomy the wound should be tightly sutured to insure the prompt reformation of the anterior chamber.

Anterior Chamber↗

PubMedDate not supplied

[Condition of ocular blood supply in patients with primary open-angle glaucoma with normal pressure].

The condition of discharge of intraocular fluid (IOF), the value of systemic arterial pressure (AP), the condition of mean dynamic arterial pressure in the ocular artery (Pm.ophth.) an the perfusion ocular pressure (Pperf.) were examined in patients with normal pressure glaucoma (NPG). A decrease in the IOF discharge from 0.16 +/- 0.02 cu mm per 1 mm Hg at the NPG initial stage to 0.11 +/- 0.01 cu mm per 1 mm Hg at the NPG deteriorated stage was established. The value of decrease of the systemic AP within an interval of 100 to 116 mm Hg is observed in patients with NPG by 6.9 times more often as compared to the controls (in 42.2% and 6.1% of cases, respectively). A reliable reduction of Pm.ophth. by 4.0 mm Hg and of Pperf.--by 4.9 mm Hg was found in patients with NPG as compared with Pm.ophth. and Pperf. in the controls with the same systemic AP values; the deficit of the ocular volumetric blood flow reached 10.9%. The treatment of NPG patients must be related with improving the IOF discharge, with reducing the genuine intraocular pressure (Po) to a tolerable level, and with increasing the systemic AP, Pm.ophth. and Pperf. to the mean statistically normal level.

Age Factors↗

PubMed1995

Immunopathological mechanisms of human T cell lymphotropic virus type 1 (HTLV-I) uveitis. Detection of HTLV-I-infected T cells in the eye and their constitutive cytokine production.

The immunopathology of human T cell lymphotropic virus type 1 (HTLV-I) uveitis was addressed by using T cell clones (TCC) established from the intraocular fluid of patients with HTLV-I uveitis. Proviral DNA of HTLV-I was identified in 55 out of 94 (59%) or 13 out of 36 (36%) TCC from the ocular fluid or the peripheral blood of these patients, respectively. Most of HTLV-I-infected TCC had a CD3+ CD4+ CD8- phenotype. HTLV-I infection on TCC was confirmed by analysis of the viral mRNA, nucleotide sequence, virus-associated proteins, and virus particles. HTLV-I-infected TCC, but not HTLV-I negative TCC, constitutively produced high amounts of IL-6 (1,336 +/- 1,050 pg/ml) and TNF-alpha (289 +/- 237 pg/ml) in the absence of any stimuli. HTLV-I-infected TCC from the ocular lesion also constitutively produced high amounts of IL-1 alpha (12,699 pg/ml), IL-2 (61 pg/ml), IL-3 (428 pg/ml), IL-8 (1,268 pg/ml), IL-10 (28 pg/ml), IFN-gamma (5,095 pg/ml), and GM-CSF (2,886 pg/ml). Hydrocortisone, a drug effective in vivo for the treatment of HTLV-I uveitis, severely depressed cytokine production in vitro in most cases. In summary, the results demonstrated direct evidence of HTLV-I infection of the eye and suggest that cytokines produced by HTLV-I-infected T cells are responsible for the intraocular inflammation in patients with HTLV-I uveitis.

Adult↗

PubMedDate not supplied

[Determination of retention during phacoemulsification with AOL in patients with open-angle glaucoma].

Phacoemulsification is the most sparing technique of cataract removal in patients with open-angle glaucoma. The retention of intraocular fluid should be determined to choose a pathogenetically oriented antiglaucoma operation for uncompensated open-angle glaucoma (OAG). The study of the Schlemm's canal retrograde blood filling phenomenon may be a technique of the most informative value. The phenomenon was studied on 102 eyes (in 82 cases of glaucoma) during phacoemulsification, which indicated the high effectiveness and safety of the use of this intraoperative method. Its advantage is that manipulations are easy-to-use and accessible. This method is of particular value in treating patients with cataract concurrent with OAG, who are to undergo phacoemulsification with a one-stage pathogenetically oriented antiglaucoma operation.

Adult↗

PubMed1989

[Change in the permeability of the blood-aqueous humor barrier in sulcus-fixed posterior capsule lenses].

In eyes in which posterior chamber lens implantation with sulcus fixation had been performed more than 2 years previously, the pathohistological findings showed that trophic changes can be caused in the area of the back surface of the iris and ciliary body. By means of fluorophotometric measurements, we studied the extent to which persistent disturbances in the blood-intraocular fluid barrier could be demonstrated postoperatively - even in eyes with no clinical evidence of impairment. Of the 33 eyes examined, 26 showed no ophthalmological findings, 2 eyes showed pronounced atrophy of the iris in the region of the adjacent lens tactile, and in 5 eyes piercing of the iris occurred through the lens haptic postoperatively. In all cases, the procedure had been performed at least 2 years ago. None of the patients noticed any impairment of vision. In the 26 eyes without ophthalmoscopically visible damage of the iris and ciliary body, there was no increase of fluorescein in the medium in the anterior chamber (mean value: -11 +/- 39). On the other hand, in the 5 eyes with perforation of the iris, there was a slight increase in the staining (mean value: +9.8 +/- 45), but it was not statistically significant.

Aqueous Humor↗

PubMedDate not supplied

The penetration of exogenous prostaglandin and arachidonic acid into, and their distribution within, the mammalian eye.

The distribution of 3H and 14C activities in intraocular fluids and tissues was studied after topical application of 3H-prostaglandin F2 alpha (3H-PGF2 alpha) and/or 14C-arachidonic acid (14C-AA) to rabbit eyes; intravenous (i.v.) infusion of 3H-PGF2 alpha into rats; and after incubation of rat or rabbit globes in media containing these and other tracers. Thirty min after topical application of 14C-AA, the order of distribution of 14C per unit of tissue weight was cornea much greater than sclera congruent to ciliary body congruent to iris congruent to aqueous greater than retina-choroid greater than vitreous greater than lens. The distribution of 3H was sclera greater than cornea greater than retina-choroid congruent to ciliary body greater than aqueous greater than vitreous (lens congruent to 0; iris congruent to 0). After i.v. infusion of 14C-sucrose and 3H-PGF2 alpha into rats for 1 to 5 min, the globe/blood ratio of 3H was significantly lower than that of 14C. When isolated rat globes were incubated, the order of tracer uptake into the whole globe was AA greater than thiourea greater than PGF2 alpha greater than sucrose, while the order of entry into the aqueous was thiourea greater than sucrose greater than AA greater than -PGF2 alpha. The isolated rabbit cornea accumulated large amounts of 14C-AA which was not readily elutable and much smaller amounts of 3H-PGF2 alpha which was readily elutable. It is concluded that the sclera is highly permeable to PGF2 alpha, but that the cornea is an effective permeability barrier to this, and presumably all other PGs. The passage of AA through the outer coats of the globe is limited by its chemical incorporation into the cornea, sclera and conjunctiva. Thus, inhibition of the adverse intraocular effects of topically applied AA by topically applied drugs may only reflect the ability of these drugs to inhibit the synthesizing capacity of the superficial layers of the globe rather than that of the anterior uvea and other intraocular tissues.

Absorption↗

PubMed1984

Experimental murine cytomegalovirus infection of ocular structures.

To study experimental cytomegalovirus (CMV) infection of ocular structures, 3-week-old Swiss-Webster mice were inoculated intraperitoneally with a 0% to 20% lethal inoculum of murine CMV (MCMV). Murine cytomegalovirus was recovered from homogenates of eye tissues on days 3, 5, and 7 after inoculation. Peak virus titers, mean of 2.93 +/- 0.67 log plaque-forming units of MCMV per gram of ocular tissue occurred on day 5. Urine cytomegalovirus was recovered from explant cultures of eye and optic nerve 14, 21, 60, 90, and 120 days after MCMV inoculation. Murine cytomegalovirus also persisted in intraocular fluids for as long as 90 days. Murine cytomegalovirus infection was confirmed by immunofluorescence antibody staining and transmission electron microscopy. These experiments indicate that MCMV infects the ocular tissues of mice during systemic MCMV infection, and persists in ocular tissues for as long as 120 days after infection. These studies may be directly relevant to ocular disorders that occur during acquired CMV infections of humans, and suggest that ocular tissues may be a site of CMV persistence or latency.

Animals↗

PubMed1985

Severe ocular injuries from orthodontic headgear.

Dislocation of extraoral orthodontic tractional devices (headgear) resulted in penetrating ocular injuries in three eyes of two patients. An endophthalmitis caused by mixed flora developed in each injured eye. Despite medical and surgical therapy, only one eye retained useful vision two years following injury. All wearers of headgear and their families should be educated in the proper use of these devices and about the potential for severe facial injuries. Penetrating ocular injuries initially may be relatively asymptomatic. Thus, even persons with seemingly minor injuries from such devices should seek immediate and thorough ophthalmic evaluation. In eyes with penetrating injuries, culture of intraocular fluids should be performed at the time of initial repair. Because the penetrating device is heavily contaminated with oral flora, broad-spectrum antibiotics should be administered by intravenous, subconjunctival, and intravitreal injection. Such injuries, although rare, may have a grave prognosis.

Adolescent↗

PubMed1997

Corneal endothelial damage by air bubbles during phacoemulsification.

OBJECTIVE: To characterize the mechanism by which air bubbles damage the corneal endothelium during phacoemulsification. MATERIALS AND METHODS: A series of experiments was conducted to expose the corneal endothelium of New Zealand white rabbit and human eyes that were obtained from an eye bank to air under different conditions. Phacoemulsification at different power settings and irrigation with and without the introduction of air into the anterior chamber were performed. Corneal endothelial perfusion experiments were conducted with air bubbles that were introduced into the perfusion chamber for 2 seconds to 1 hour. Air was also injected into the anterior chambers of anesthetized rabbits for 2 minutes to 3 hours. Corneas were stained with nitrobenzo-xadiazole-phallacidin and examined with fluorescence microscopy. Selected corneas were also examined with scanning and transmission electron microscopy. RESULTS: Intracameral air bubbles during phacoemulsification, irrigation, and perfusion studies resulted in a severe injury to the corneal endothelium in as little as 20 seconds. Intracameral air bubbles in a living rabbit resulted in a slower injury that was morphologically different from the more rapid injury. CONCLUSIONS: Air bubbles in intraocular fluids with a high surface tension can cause a ring-shaped pattern of damage to the corneal endothelium. The mechanism that caused this pattern of damage appears to be a surface tension phenomenon.

Air↗

PubMed2002

Biocompatibility assessment of silicone oil and perfluorocarbon liquids used in retinal reattachment surgery in rat retinal cultures.

The effects of silicone oil and perfluorocarbon liquids used in retinal reattachment surgery were studied in vitro using rat retinal cultures seeded on microporous inserts. These inserts allow the cell layer to be in contact with the material to be tested on the apical side and with the nutrient medium on the basal side. The materials tested were silicone oil, the perfluorocarbons perfluorophenanthrene and perfluoroctane, and hydroxypropylmethylcellulose. Perfluorophenanthrene, the heaviest of the compounds, induced a very precocious detachment of the cell layer. All the other tested biomaterials were compatible with cell survival and did not alter the structural organization of the retinal cultures, as revealed by scanning electron microscopy. By immunocytochemical techniques we evaluated the cell composition and the differentiation state of each of the cultures. In both control and treated samples, neuronal cells were well preserved. The expression of microtubule-associated protein 2, a marker of differentiated neuronal cytoskeleton, was not affected. Amacrine neurons, immunolabeled for gamma-aminobutyric acid, still were detectable after treatment. Synapses, marked by immunoreactivity for synapthophysin, were equally preserved. Vimentin-positive glial cells did not show modifications. The apoptotic rate, as determined by the terminal transferase-mediated dUTP-biotin nick end-labeling assay, was similar in treated and control samples. The results confirm that the use of biomaterials with a specific gravity close to intraocular fluids is compatible with retinal cell survival and differentiation in vitro.

Animals↗

PubMed1986

Beta-N-acetyl-glucosaminidase: possible role in ocular neovascularization.

The possibility that lysosomal enzymes might be involved as angiogenic factors in ocular neovascularization (NV) was investigated. Beta-N-acetyl-glucosaminidase (NAGase) activity, and that of two other glycosidases, were present in the retinal derived protein fraction (RDPF) reported by others to be angiogenic. NAGase, but not the other glycosidases, was inhibited by vitreous. NAGase exhibited the same stability characteristics as RDPF. In diabetic rats there was a significant rise in vitreous but a fall in retinal NAGase activity. The sera of these animals, however, showed elevation in the activities of all five glycosidases. Preliminary experiments indicate that only the intermediate isoenzyme of NAGase, putatively insulin dependent, is elevated in the eyes of these diabetic rats. NAGase was also specifically elevated in the intraocular fluid from monkey eyes with retinal vein occlusion (RVO), and markedly so if NV was present. These results suggest the involvement of NAGase in the neovascular process in the eye.

Acetylglucosaminidase↗