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Results for “INTRAOCULAR PRESSURE”

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At least 811 records · Page 45Linked to original sources

PubMed1983

Preoperative use of the Honan intraocular pressure reducer.

After administering a retrobulbar injection of anesthesia, we applied the Honan intraocular pressure reducer at a pressure of 30 mm Hg for five minutes to 48 nonglaucomatous eyes and eight glaucomatous eyes undergoing cataract extraction. This technique resulted in mean intraocular pressure reductions of 6.52 mm Hg in the nonglaucomatous eyes (P less than .001) and 10.13 mm Hg (P = .013) in the glaucomatous eyes. These results were comparable to those achieved by using the same device for 40 or more minutes.

Cataract Extraction↗

PubMed1976

Blood-aqueous barrier can be circumvented by lowering intraocular pressure.

Rhesus monkeys were injected intravenously with hypertonic urea (9 ml/kg body weight of 30% urea in 10% invert sugar) and the intraocular pressure was measured with an applamatic tonometer. When this pressure reached its minimum (20% of the normal value) horseradish peroxidase (molecular weight 40,000; radius of an equivalent hydrodynamic sphere about 2.5 nm; 0.5 g/kg body weight), was injected intravenously. Twenty minutes following peroxidase administration, either aqueous humor was sampled from the anterior chamber for biochemical determination of peroxidase activity, or one eyeball was enucleated and processed for light and electron microscopic localization of the enzymatic tracer. This experiment showed that: (1) therapeutic doses of hypertonic urea do not cause a breakdown of either the blood-retina or the blood-aqueous barriers; (2) as intraocular pressure decreases, peroxidase-containing blood flows back from the episcleral veins into the Schlemm canal; (3) macromolecules up to the dimensions of horseradish peroxidase leak through the intercellular clefts of the endothelium of the Schlemm canal, permeate the juxtacanalicular connective tissue and trabecular meshwork, and finally enter the anterior chamber. Thus, blood-borne substances can circumvent the blood-aqueous barrier when intraocular pressure is decreased, and administration of a hypertonic agent may represent a simple pharmacological device to cause penetration into the ocular chambers by drugs that are normally excluded from the interior of the eye.

Animals↗

PubMed2001

Effect of tracheal intubation or laryngeal mask airway insertion on intraocular pressure using balanced anesthesia with sevoflurane and remifentanil.

STUDY OBJECTIVES: To study the effect of tracheal intubation or laryngeal mask airway (LMA) insertion on intraocular pressure (IOP) in strabismus patients undergoing balanced anesthesia with sevoflurane and remifentanil. DESIGN: Open, prospective, randomized study. SETTING: Tertiary care academic medical institution. PATIENTS: 40 adult ASA physical status I and II patients scheduled for elective strabismus surgery. INTERVENTION: Patients were randomized to receive either tracheal intubation or LMA insertion following mask induction with sevoflurane in combination with IV remifentanil. MEASUREMENTS: Intraocular pressure, mean arterial pressure (MAP), and heart rate (HR) were measured before induction, immediately following induction, and after airway insertion. MAIN RESULTS: Intraocular pressure after tracheal intubation or LMA insertion did not differ significantly from preoperative baseline values. Mean arterial pressure and HR did not significantly differ between groups at any time point. CONCLUSIONS: Remifentanil and sevoflurane are not associated with an increase in IOP response during tracheal intubation or LMA insertion above baseline in healthy patients undergoing ophthalmic surgery.

Adjuvants, Anesthesia↗

PubMed2001

[The cause and management of acute high intraocular pressure in phacoemulsification].

OBJECTIVE: To investigate the cause and management of acute high intraocular pressure and shallow anterior chamber in phacoemulsification. METHODS: A retrospective study was done on 1,500 eyes performed phacoemulsification. Eleven of 1,500 eyes showed higher intraocular pressure and shallowing of the anterior chamber during phacoemulsification. But phacoemulsification was successfully achieved after giving hyperosmotic agents, increasing infusion pressure and reducing aspiration rate as well as flow rate. RESULTS: Of 11 eyes, 10 eyes were treated by management of non vitrectomy. One of 11 eyes was unresponsive to medical management and require the use of pars plana vitrectomy. Phaco was performed in all patients. In 4 of 11 eyes, visual acuity postoperatively were 0.7 or better. Five of 11 eyes were 0.3 to 0.5. One eye was 0.05 and one was HM/30 cm. CONCLUSION: Aqueous misdirection, retrobulbar hemorrhage and intraoperative suprachoroidal hemorrhage are common causes of acute high intracular pressure in phaco. Most of patients could be performed phaco after medical treatment. If patients failed to improve after medical treatment, par plana vitrectomy is a useful method.

Aged↗

PubMed2004

Intravitreal triamcinolone acetonide and intraocular pressure.

PURPOSE: To analyze the incidence of intraocular pressure (IOP) elevation following intravitreal triamcinolone injection. DESIGN: Retrospective observational case series. METHODS: Charts of patients undergoing intravitreal triamcinolone injection in one clinical practice were reviewed. A pressure elevation was defined as a pressure of 24 mm Hg or higher during follow-up. RESULTS: There were 89 patients with a mean age of 76.4 years. The mean baseline IOP was 14.9 mm Hg with a mean change of 8.0 mm Hg. Thirty-six patients (40.4%) experienced a pressure elevation to 24 mm Hg or higher at a mean of 100.6 days (SD = 83.1 day) after treatment. Of nonglaucomatous patients with baseline IOP of 15 mm Hg or above, 60.0% experienced a pressure elevation, compared with only 22.7% of those with baseline pressures below 15 mm Hg (relative risk = 2.1, P < .01). In glaucoma patients, 6 of 12 (50%) experienced a pressure elevation, and this elevation was not correlated with baseline pressure. Thirty-two patients (36.0%) received repeat injections, and there was no difference in the incidence of procedure elevation in patients receiving multiple injections versus those receiving a single injection. Pressure elevation was controlled with topical medications in all patients. CONCLUSIONS: IOP elevation after intravitreal triamcinolone injection is common and may take an extended period of time to manifest. The proportion of patients who developed a pressure elevation to at least 24 mm Hg was much higher for those with baseline IOP 15 mm Hg or greater.

Adult↗

PubMed1991

Measurement of intraocular pressure with a flat anterior chamber.

When a flat chamber develops in an eye after filtration surgery, management depends on whether the cause is excessive filtration or aqueous misdirection (ciliary block or malignant glaucoma). This diagnosis is often based on the intraocular pressure: low pressure in excessive filtration, high pressure in aqueous misdirection. To determine the accuracy of tonometry when the lens is in contact with the cornea, flat anterior chambers were created in 5 eyes obtained from an eye bank. The pressure in the vitreous cavity was raised and lowered with an infusion line and monitored with a pressure transducer. The intraocular pressure was estimated with a Goldmann applanation tonometer, a Pneumatonometer, and a Tono-pen. The readings poorly represented the actual pressure in the vitreous cavity. The error was 0 to 51 mmHg (mean, 12.8 mmHg) with the Goldmann tonometer, 0 to 33 mmHg (mean, 9.0 mmHg) with the Pneumatonometer, and 1 to 28 mmHg (mean, 13.5 mmHg) with the Tono-pen. Therefore, in the face of a flat anterior chamber, pressure measurements made on the cornea cannot be relied on to distinguish excessive filtration from aqueous misdirection.

Anterior Chamber↗

PubMed1998

Changes in intraocular pressure due to cycloplegia.

PURPOSE: We studied intraocular pressure (IOP) in a group of healthy myopic subjects before and after administration of chlorhydrate cyclopentolate 1%. METHODS: We measured the IOP before administration and at 15, 30, 45, 60, and 300 minutes and 24 hours after administration. RESULTS: The rise in IOP at 15 and 300 minutes was not significant (P > 0.05), while the rise at 30, 45, and 60 minutes was significant (P < 0.05). The increase reached its maximum at 45 minutes. At 300 minutes, the increase was almost completely overcome and was not significant. At 24 hours, the pressure had returned to initial values. CONCLUSIONS: Cyclopentolate represents a valuable aid in performing retinoscopy in healthy subjects who have an anterior chamber with adequate depth and an open angle.

Adolescent↗

PubMed1992

[Intraocular lens implantation after glaucoma filtering surgery--time course of changes in intraocular pressure control and filtering blebs].

Cataract extraction and intraocular lens (IOL) implantation were carried out in 45 glaucomatous eyes that had undergone glaucoma filtering surgery. Of these, 37 eyes had primary glaucoma, 2 eyes capsular glaucoma, and 6 eyes secondary glaucoma. The visual acuity after IOL implantation was 0.5 or more in 29 eyes (64%) but in 10 eyes (22%) acuity was 0.1 or less because of advanced optic nerve head damage. To analyze affects of IOL implantation on intraocular pressure (IOP) control and functioning of the filtration bleb in 39 eyes of primary or capsular glaucoma, a life-table analysis with the Kaplan-Meier method was performed. The probability that IOP control does not worsen at 2 years was 43 +/- 7% (SE) in 21 eyes without pre-operative ocular hypotensive medication, 56 +/- 16% in 18 eyes with pre-operative ocular hypotensive medication, 47 +/- 12% in 26 eyes where functioning filtering bleb existed pre-operatively. The probability that the filtering bleb survives 2 years post-operatively was 44 +/- 11%. The present results imply that intensive management of post-operative inflammation and careful IOP follow up are imperative in eyes in which IOL implantation was indicated after undergoing filtration surgery.

Aged↗

PubMed1985

Intraocular pressure in uremic patients on chronic hemodialysis.

Intraocular pressure (IOP) was measured before and after hemodialysis in 30 uremic patients receiving regular treatment. Osmolality, blood pressure and weight before and after dialysis were also determined. Low IOP of 11.4 +/- 2.7 and 11.5 +/- 3.1 mm Hg was found in the left and right eye, respectively. Following hemodialysis osmolality, blood pressure and body weight decreased significantly but IOP did not rise significantly. This study suggests that there is only a remote possibility for severe IOP increase following hemodialysis in uremic patients on chronic treatment.

Adolescent↗

PubMed1995

Intraocular pressure seven years after extracapsular cataract extraction and sulcus implantation of a posterior chamber intraocular lens.

Seven years after extracapsular cataract extraction (ECCE) and sulcus implantation of a posterior chamber intraocular lens, we measured the intraocular pressure (IOP) in 28 eyes of 28 patients. The results were compared with the preoperative IOP and with the postoperative IOP at four months and 2 1/2 years. The mean IOP value seven years after surgery was 1.3 mm Hg lower than the preoperative mean value. No significant difference was found among the values at four months, 2 1/2 years, and seven years. One patient experienced a marked rise in IOP between 2 1/2 years and seven years and was excluded from the calculations. However, we could not tell whether it was a consequence of the cataract surgery. In this study, we found that IOP stabilized at a postoperative level that was significantly lower than the preoperative value and has remained there for seven years.

Aged↗

PubMed2003

Effect of soft contact lenses on the measurements of intraocular pressure with non-contact pneumotonometry.

PURPOSE: To evaluate the effect of soft contact lenses with different lens power on the measured value of the intraocular pressure with non-contact pneumotonometry. METHODS: 120 eyes (80 healthy volunteers: 50 women, 30 men, aged 22 to 61 years) were included in this study. Intraocular pressure was measured with a pneumotonometer Canon X-10 before and after insertion of the Ciba Vision Focus Night&Day soft contact lens. We used contact lenses with different lens power of + 0.25 D, + 1.00 D, + 4.00 D, - 1.00 D, and - 4.00 D. The averages of three measurements were taken as representative IOP values that were statistically evaluated. RESULTS: IOP measured over myopic lenses of - 1.00 and - 4.00 D showed lower values within the mean range of 1 mm Hg. The difference between the measurements over the myopic lenses was mostly smaller than +/- 2 mm Hg (78% when using - 1.00 D and 90% when using - 4.00 D contact lens). All the differences using + 0.25 D contact lens were smaller than +/- 2 mm Hg. The difference was considerably higher in measurements over + 1.00 and + 4.00 hyperopic contact lenses and showed strong increase with the lens power. CONCLUSIONS: In our study we showed that intraocular pressure can be reliably measured with non-contact pneumotonometry over myopic lenses or hypermetropic lenses with small lens power. This suggests that non-contact pneumotonometry is a useful method in patients wearing therapeutic contact lenses and contact lens wearers who, when measuring the eye pressure, would not need to remove the contact lenses before the examination.

Adult↗

PubMed1991

Intraocular pressure asymmetry in a population tested with the Pulsair non-contact tonometer.

Intraocular pressure asymmetry as measured by noncontact tonometry (NCT) was analysed in a population of 874 individuals aged over 50 years. In both males and females the intraocular pressure (IOP) measured in the right eye exceeded that of the left. Pressure asymmetry followed a normal distribution in a population subgroup known to have normal fields, discs and pressures. The 95% confidence intervals for the equation R IOP--L IOP in normals were 0.63+ or -5.46 mmHg when the mean of four pulses per eye were used to calculate the IOP, increasing to 0.80+ or -6.56 mmHg for two pulses per eye (thus expanding the limits by 20%). The range of asymmetry for NCT in normals therefore exceeds that reported for Goldmann applanation tonometry. Asymmetry was greater in females than males. Knowledge of the normal range of IOP asymmetry in each sex will help glaucoma screeners using NCT in their decision as to when to refer. A minimum of four pulses per eye should be used to assess the IOP when screening.

Aged↗

PubMed1982

[Perimetric and visumetric methods for measuring individually tolerated intraocular pressure in glaucoma].

These techniques are used in far-advanced cases of glaucoma when the campimetric method is not practicable due to a considerable loss of visual field. The patient takes a mixture of glycerol and ascorbic acid as a hypotensive agent, his visual field or visual acuity and intraocular pressure are checked every 30 minutes. The intraocular pressure determined together with the maximum field size or with the best visual acuity is considered the individually tolerated value. The average was 21.9 mmHg. The aim in treating glaucoma should be to maintain an intraocular pressure not exceeding the tolerated value; if this cannot be achieved with drug therapy surgery is indicated.

Glaucoma↗

PubMed1983

Immediate intraocular pressure response to argon laser trabeculoplasty.

We conducted a randomized, double-masked study of 40 patients with open-angle glaucoma to ascertain the immediate intraocular pressure response after treatment of either one half (180 degrees) or the entire (360 degrees) trabecular meshwork by argon laser trabeculoplasty. We found a statistically significant difference in the magnitude of intraocular pressure changes between the two groups (P less than .02), with those patients receiving fewer burns having a smaller increase. Substantial increases in intraocular pressure were observed in five of the 20 patients in whom the entire trabecular meshwork was treated. One of these patients had marked loss of visual field within 24 hours.

Adult↗

PubMed2001

Involvement of melatonin MT(3) receptors in the regulation of intraocular pressure in rabbits.

Melatonin, a neurohormone secreted by the pineal gland, can stimulate three subtypes of receptors, namely: mt(1), MT(2) and MT(3). We examined the ability of melatonin and the selective MT(3) receptor agonist, 5-methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT), to modify intraocular pressure in rabbits. Both compounds significantly reduced intraocular pressure, maximally by 24% and 43%, respectively, with IC(50) values of 363+/-23.0 and 423+/-30.0 ng/10 microl (1.6+/-0.1 and 1.8+/-0.1 nmol, respectively). The non-specific melatonin receptor antagonist, luzindole, abolished the depressant effect of both compounds, thus confirming the involvement of melatonin receptors. Our results show, for the first time, a functional response that may be regulated by melatonin MT(3) receptors, and provide evidence that supports a role of melatonin in the circadian changes of intraocular pressure.

Animals↗

PubMed1998

Circadian rhythm of intraocular pressure.

Although it is well known that intraocular pressure (IOP) in humans varies throughout day and night, no consistent circadian pattern has been established. In laboratory rabbits, however, a consistent circadian rhythm of IOP has been confirmed and further characterized in recent years. The current knowledge about the nocturnal IOP elevation in rabbits is reviewed and the implications for the study of human circadian IOP pattern is discussed.

Animals↗

PubMed2006

Ocular response analyzer versus Goldmann applanation tonometry for intraocular pressure measurements.

PURPOSE: To establish correlations between intraocular pressure (IOP) measurements obtained with the ocular response analyzer (ORA) and the Goldmann applanation tonometer (GAT). The effects of central corneal thickness on the measures obtained were also examined. METHODS: This was a cross-sectional study. IOP was determined in 48 eyes of 48 patients with glaucoma In all patients, central corneal thickness (CCT) was measured by ultrasound pachymetry. RESULTS: ORA readings were consistently higher than GAT measurements (Goldmann-correlated IOP - IOP GAT mean difference, 7.2 +/- 3.5 mm Hg; corneal-compensated IOP - IOP GAT mean difference, 8.3 +/- 4.0 mm Hg) However, differences were not constant and increased with increasing IOP GAT readings, both with respect to Goldmann-correlated IOP (slope = 0.623, P < 0.0001) and corneal-compensated IOP (slope = 0.538, P < 0.0001). Both pressure measurements provided by the ORA showed significant correlation with CCT (CCT versus Goldmann-correlated IOP: r = 0.460, P = 0.001; CCT versus corneal-compensated IOP: r = 0.442, P = 0.001). No significant effects of corneal curvature or refraction on any of the pressures were observed. CONCLUSIONS: The ORA significantly overestimates IOP compared with the GAT. Differences between both sets of measures increase as the GAT-determined IOP increases. ORA readings seem to be affected by central corneal thickness.

Aged↗

PubMed2001

Intraocular pressure of juvenile loggerhead sea turtles (Caretta caretta) held in different positions.

The intraocular pressure of 12 apparently healthy juvenile loggerhead sea turtles (Caretta caretta) was determined by applanation tonometry while the turtles were held in dorsoventral, ventrodorsal, and head-down suspended positions. The median intraocular pressures were 5 mmHg (range 4 to 9 mmHg) in the dorsoventral position, 7 mmHg (range 5 to 12 mmHg) in the ventrodorsal position, and 23 mmHg (range 17 to 33 mmHg) in the suspended position.

Animals↗