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Results for “INTRAOCULAR PRESSURE”

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At least 793 records · Page 44Linked to original sources

PubMed1998

Effect of intracameral administration of carbachol on the postoperative increase in intraocular pressure in dogs undergoing cataract extraction.

OBJECTIVE: To determine whether intracameral injection of carbachol at the completion of phacoemulsification in dogs would prevent the increase in intraocular pressure (i.o.p) that can develop during the first 24 hours after surgery. DESIGN: Randomized controlled trial. ANIMALS: 32 adult dogs undergoing elective unilateral or bilateral phacoemulsification. PROCEDURE: Dogs were randomly assigned to 1 of 4 groups with 8 dogs/group: phacoemulsification and intracameral administration of 0.5 ml of 0.01% carbachol at the end of surgery; phacoemulsification, intraocular lens implantation, and intracameral administration of 0.5 ml of 0.01% carbachol; phacoemulsification and intracameral administration of 0.5 ml of balanced salt solution; and phacoemulsification, intraocular lens implantation, and intracameral administration of 0.5 ml of balanced salt solution. Intraocular pressure was measured at 3 and 6 hours and the morning after surgery. Aqueous flare was also measured 6 hours and the morning after surgery. RESULTS: None of the dogs treated with carbachol developed postoperative ocular hypertension (i.e., IOP > 27 mm of Hg), whereas 12 of 16 control dogs had ocular hypertension 3 hours after surgery. Intraocular pressure 3 hours after surgery was not significantly associated with phacoemulsification time or phacoemulsification power or with whether the dog received an intraocular lens implant. Severity of aqueous flare was similar for treated and control dogs. CLINICAL IMPLICATIONS: Results suggested that intracameral administration of 0.01% carbachol at the end of surgery was a safe and efficacious method of preventing the postoperative increase in IOP associated with phacoemulsification in dogs.

Animals↗

PubMed1987

Iloprost, a stable prostacyclin analog, reduces intraocular pressure.

Topical application of Iloprost caused a dose-dependent decrease in intraocular pressure (IOP) in rabbits and ocular hypertensive beagles. In rabbits, the IOP response was biphasic and miosis was observed. In beagles, there was no initial hypertensive phase, and the fall in IOP was more pronounced (up to 37%). In beagles, Iloprost did not influence pupillary diameter. A mild transient hyperemia was noted in both rabbit and beagle eyes. Iloprost led to an increase in the aqueous humor protein concentration in rabbits but not in beagles. The use of artificial tears as vehicle enhanced the effect on intraocular pressure but also aqueous protein in rabbits. The central corneal temperature was increased after application of Iloprost in both rabbits and beagles. In rabbits, tonography revealed an increase in outflow facility during both the hypertensive and the hypotensive phases. Iloprost caused a decrease in mean arterial pressure in beagles; the effect on pulse rate was inconsequential. It is suggested that similar low doses of an analog of Iloprost or carboprostacyclin that does not affect the hemodynamic equilibrium could be of value in the treatment of glaucoma.

Animals↗

PubMedDate not supplied

Elevated intraocular pressure, pigment dispersion and dark hypopyon in endogenous endophthalmitis from Listeria monocytogenes.

Listeria monocytogenes endophthalmitis occurred in an immunologically competent patient with no identifiable extraocular septic focus. The patient presented with a dark hypopyon and markedly elevated intraocular pressure, and the diagnosis was established by culture and histopathologic examination of ocular fluid. Four of the fourteen reported cases of Listeria monocytogenes endophthalmitis also presented with a dark hypopyon, and all cases had markedly elevated intraocular pressure. The presence of a dark hypopyon and elevated intraocular pressure may indicate endogenous intraocular infection with Listeria monocytogenes, even in an apparently healthy host.

Aged↗

PubMed2002

Relationship between intraocular pressure and systemic health parameters in the Korean population.

This study examined the influence of age, sex, blood pressure, and obesity index on intraocular pressure (IOP), in order to investigate the relationship between the upper limits of the following two conditions in the general Korean population: the "systolic or diastolic hypertensive and obese" group and the "systolic or diastolic hypotensive and lean" group. A total of 6828 healthy subjects (13,656 eyes) underwent automated multi-phasic tests, including tonometry, blood pressure, visual field, and body mass index. The 6,828 subjects were divided into five groups based on age; less than 40, 40 to 49, 50 to 59, 60 to 69, and over 70 years old. They were also divided into four categories on the basis of sex, age, blood pressure, and obesity index. The mean IOP in males (15.8+/-3.3 mmHg) was significantly higher than in females (14.8+/-3.1 mmHg) (P < 0.05), but this difference decreased proportionally with increasing age. IOP had a tendency to decrease with increasing age (P < 0.05). IOP increased significantly with increasing systolic blood pressure, diastolic blood pressure and obesity index (all, P < 0.05). The mean IOP of the "systolic or diastolic hypertensive and obese" group was higher than that of the "systolic or diastolic hypotensive and lean" group in the general Korean population (P < 0.05). These data could aid investigation into the epidemiological, etiologic and oriental influences related to the risk factors of glaucoma, especially in oriental populations.

Adult↗

PubMed1979

Interaction of atenolol and adrenaline with respect to intraocular pressure.

1. The effects of topically administered atenolol 4% and adrenaline 1% on intraocular pressure (IOP) were investigated in fourteen healthy male human volunteers. Both the sole and combined effects of single doses of the formulations were recorded over a 7 h period. 2. Adrenaline and atenolol both produced significant reductions in IOP when compared to the placebo control, although the pattern of response differed. 3. Adrenaline had a rapid onset of action, resulting in a significant pressure reduction by 45 min post drug administration. A small upswing in IOP then occurred between 45 and 90 min, followed by a prolonged secondary reduction phase. 4. Atenolol produced a gradual reduction in IOP which reached a maximum at 180 min post drug administration and subsequently declined between 300 and 420 min. 5. Combined treatment with atenolol and adrenaline resulted in additive effects up to 180 min, and the early pressure upswing recorded with adrenaline was completely abolished. 6. The results are compatible with the hypothesis that beta 1-adrenoceptor stimulation elevates intraocular pressure. The correlation of these results with relevant animal and human pharmacological data is discussed.

Adult↗

PubMed2004

Trabecular bypass stents decrease intraocular pressure in cultured human anterior segments.

PURPOSE: To determine the effect on intraocular pressure (IOP) of bypassing the trabecular meshwork in cultured human anterior segments. DESIGN: Prospective laboratory investigation using normal human eyes obtained at autopsy. METHODS: Anterior segments from 21 eyes were placed in perfusion culture, and trabecular bypass stents were inserted through the trabecular meshwork, with the lumen of the tube opening into Schlemm's canal. Eyes received from one to four stents, placed equidistant apart. In eyes receiving one or two stents, additional stents were later added to a maximum of four per eye. RESULTS: Intraocular pressure was lowered after placement of a single stent, from 21.4 +/- 3.8 mm Hg to 12.4 +/- 4.2 (P < .001). This corresponded to an 84% increase in facility of outflow. Eyes receiving more than one stent had final IOP of 11.9 +/- 3.7 mm Hg. Nine eyes had sequential addition of stents, and seven of these had a further decrease of IOP (13.6 +/- 4.1 to 10.0 +/- 4.3; P = .02). Excision of the entire meshwork, between stents, dropped IOP to 6.3 +/- 3.2 mm Hg, indicating some residual meshwork or canal resistance remained even after placement of three stents. CONCLUSIONS: Bypass of the trabecular meshwork lowers IOP in cultured human anterior segments. One stent produced the greatest change in pressure. The sequential addition of more stents further lowered pressure in seven of nine eyes. This technique holds promise as a new clinical surgery for glaucoma.

Anterior Eye Segment↗

PubMed1996

Comparison of the effect of four viscoelastic agents on early postoperative intraocular pressure.

PURPOSE: To compare the effect of four commercially available viscoelastic agents on postoperative intraocular pressure (IOP). SETTING: Four outpatient sites. METHODS: Sixty-nine patients having routine extracapsular cataract extraction were enrolled in the study; 54 were available for a 3 month follow-up examination. The four viscoelastic agents were Amvisc, Amvisc Plus, Healon, and Viscoat. Intraocular pressure was measured preoperatively and at 2, 3, 4, 5, 6, 8, 10, 12, and 24 hours and 3 months postoperatively. Pachymetry and endothelial cell counts were performed preoperatively and 3 months postoperatively. RESULTS: Mean postoperative IOP and IOP changes from baseline did not differ among the four treatment groups at any time. However, when mean maximal IOP was compared, the Healon group demonstrated the highest IOP increases (P = .0033). There was also a significant difference (P = .0015) among the treatment groups in the mean maximum postoperative change from baseline; the Healon group exhibited the largest mean change in IOP. At 3 months postoperatively, IOP values and pachymetry were normal for all treatment groups and were not statistically different among groups, indicating the four agents provided similar degree of endothelial protection and IOP stability. CONCLUSION: These results suggest that IOP increases occur in varying degrees and at varying times in the early postoperative period after cataract surgery using a viscoelastic agent.

Adolescent↗

PubMed1999

Intraocular pressure changes during rapid sequence induction and intubation: a comparison of rocuronium, atracurium, and succinylcholine.

STUDY OBJECTIVE: To compare changes in intraocular pressure (IOP) during rapid sequence induction and intubation following rocuronium, succinylcholine, and atracurium. DESIGN: Open-label, prospective, randomized study. SETTING: Operating room at the Eye Foundation Hospital (University of Alabama at Birmingham) PATIENTS: 45 ASA physical status I, II, and III patients, aged 18 to 65 years, scheduled for elective eye surgery with general anesthesia. INTERVENTIONS: Anesthesia was rapidly induced in unpremedicated patients with a fixed combination of midazolam 0.025 mg/kg, alfentanil 0.025 mg/kg, and propofol 1.5 mg/kg. Intubation was performed, as clinically indicated, approximately 60 seconds following administration of rocuronium 0.6 mg/kg, atracurium 0.5 mg/kg, or succinylcholine 1 to 1.5 mg/kg. MEASUREMENTS AND MAIN RESULTS: Intraocular pressure was measured before induction of anesthesia (baseline), following anesthesia induction and administration of muscle relaxant (before intubation), and after intubation. The percent change in IOP from baseline was significantly decreased in the rocuronium group compared with the succinylcholine group (p = 0.046) before intubation. This trend continued after intubation, but the difference was no longer significant (p = 0.070). Intubation scores for rocuronium and succinylcholine groups were similar, and both scores were superior to that for the atracurium group (p = 0.002). CONCLUSION: Intraocular pressure can be controlled during emergency induction of anesthesia and intubation with adequate depth of anesthesia and muscle relaxation. Rocuronium, succinylcholine, and atracurium all provided sufficient muscle relaxation to achieve successful intubation and no increase in IOP. However, rocuronium 0.6 mg/kg provided significantly better intubating conditions compared with atracurium, and it resulted in a significantly greater decrease in IOP compared with baseline than succinylcholine.

Adolescent↗

PubMed1999

[Studies of the mechanism of lowering intraocular pressure on Erycibele alkaloid].

OBJECTIVE: To investigate the molecular pharmacological mechanism of lowering intraocular pressure of Erycibele alkaloid. METHODS: Rabbit pupil diameter was measured by a pupillary ruler in constant illumination and the intraocular pressure (IOP) was measured by pneumatonometer. Iris contracting force was measured in an experiment of isolated rabbit iris. Radioimmune method was used to determine the content of cyclonucleotide. RESULTS: The pD(2) value (the affinity to M-receptors of agonist) of Erycibele alkaloid's miosis is 3.60 +/- 0.15 and its IOP lowering action is 3.49 +/- 0.07. In the isolated iris contracting experiment, its pD(2) value is 6.38 +/- 0.12. M(3) receptor antagonist is the strongest antagonist in inhibiting the miosis, IOP lowering action and isolated iris pupillary contracting action of Erycibele alkaloid. 0.01% Erycibele alkaloid can cause the decrease of cAMP and the increase of cGMP in the aqueous humor. CONCLUSIONS: The effects of miosis and IOP lowering of Erycibele alkaloid are all mediated by M(3) receptor subtype and its signal transductive mechanism is connected with cyclic nucleotide system.

Animals↗

PubMed1993

A double-masked comparison of betaxolol and dipivefrin for the treatment of increased intraocular pressure.

Noncardioselective beta-adrenoceptor antagonists are used for treatment of increased intraocular pressure. Because these agents may be absorbed systemically, their use is of concern in patients with restricted pulmonary function. We compared the efficacy of betaxolol, a cardioselective beta-adrenoceptor antagonist, and dipivefrin, an alpha/beta-adrenergic agonist. Seventy-six patients with open-angle glaucoma or ocular hypertension were randomly assigned to receive either betaxolol 0.5% or dipivefrin 0.1%. Patients were examined at two weeks, one month, two months, and three months. Intraocular pressure reductions were similar, with a mean decrease of 4.1 mm Hg in the betaxolol group and 3.5 mm Hg in the dipivefrin group. Both treatments caused similar minor increases in heart rate, typical with alpha-adrenergic agonists but atypical with beta-blockers. Stinging or burning in the betaxolol group was significantly (P = .008) greater than in the dipivefrin group. Our findings suggest that betaxolol and dipivefrin therapy are effective, equivalent ocular hypotensive agents.

Aged↗

PubMed1980

The endothelial cell damage in acute glaucoma. On the corneal thickness response to intraocular pressure.

In order to assess a possible damage to the corneal endothelium during pressure induced abnormal hydration of the cornea, 23 patients with a previous attack of unilateral acute glaucoma were photographed with a specular microscope. As compared to the healthy side, the endothelium of the affected side showed a mean decrease in cell density of 23.1%, range --4.8 to 68% (P less than 0.001). In retrospect this cell loss was found to correlate significantly to the increase in corneal thickness measured during the acute attack on first day of admission. At present examination mean central corneal thickness was identical in the affected and unaffected eye. A large variation was, however, found in the intraocular pressure of the previously attacked eye. If the subject inter-eye difference in intraocular pressure was related to the inter-eye difference in corneal thickness is significant negative correlation appeared. It is concluded that the intraocular pressure has a dual effect on the corneal hydration: if the endothelium is intact, the intraocular pressure decreases corneal thickness, whereas an increase is seen only if the endothelium is acutely damaged.

Acute Disease↗

PubMed1984

[Intraocular pressure and the trigeminal ganglion].

The way in which aqueous humor secretion and intraocular pressure are regulated is not well known. In order to shed light on the role played by the sensory nervous system in this regulation, hourly intraocular pressure measurements were made on patients who had undergone surgery of the first branch of the trigeminal nerve.

Aged↗

PubMedDate not supplied

Effect of 0.2% brimonidine in preventing intraocular pressure elevation after Nd:YAG laser posterior capsulotomy.

BACKGROUND AND OBJECTIVE: To determine the prophylactic effect of 0.2% brimonidine in reducing the elevated intraocular pressure (IOP) in patients undergoing Nd:YAG laser posterior capsulotomy. PATIENTS AND METHODS: The 81 patients (81 eyes), who underwent Nd:YAG laser posterior capsulotomy, were allocated to two treatment groups. One drop of 0.2% brimonidine or vehicle was instilled 1 hour preoperatively and one drop immediately after capsulotomy. IOPs were measured preoperatively and 1, 2, 3, and 24 hours postoperatively. RESULTS: Intraocular pressure decreased from the baseline in the brimonidine group by the third postoperative hour (P<0.05), while the vehicle group exhibited an increase. Intraocular pressure elevations of 5 mm Hg or greater occurred in 7.3% (3/41) in the brimonidine group compared to 20.0% (8/40) in the vehicle group. IOP elevations of 10 mm Hg or greater occurred in 2.4% (1/41) in the brimonidine group compared to 7.5% (3/40) in the vehicle group. CONCLUSIONS: One drop of 0.2% brimonidine instilled 1 hour preoperatively and immediately after capsulotomy was found to be efficacious and safe in preventing IOP elevations that frequently follow Nd:YAG laser posterior capsulotomy.

Adrenergic alpha-Agonists↗

PubMed1998

Incidence of elevation of intraocular pressure over time and associated factors in normal-tension glaucoma.

PURPOSE: The authors determine whether intraocular pressure (IOP) increases to levels that challenge the diagnosis of normal-tension glaucoma (NTG) and determine clinical factors associated with the IOP elevation. METHODS: Forty patients with NTG who met the following enrollment criteria were selected: IOPs less than 21 mm Hg during initial 24-hour pressure curve and throughout the subsequent 12 months; examined every 1 to 4 months for at least 4 years; and no ocular hypotensive treatment. The eye with the higher mean IOP during the initial 24-hour pressure curve was selected from each patient. The observation period ranged from 4.0 years to 7.8 years (mean, 5.2 years). Significant IOP elevation was defined as a significant increase (p < 0.05) of IOP over time, determined by Spearman rank correlation coefficient method. The IOP elevation was correlated to clinical factors by means of a logistic multiple regression analysis (LOGIST procedure using PC-SAS, SAS Institute, Inc. Cary, NC, U.S.A.). RESULTS: Eleven eyes were rated positive for IOP elevation. The regression model demonstrated that maximum IOP during the initial 24-hour pressure curve and the development of disc hemorrhage (DH) were significantly correlated with IOP elevation (p = 0.006 and p = 0.049, respectively). The odds ratios calculated were 1.98 per 1 mm Hg rise of maximum IOP during the initial 24-hour pressure curve and 6.54 for positive DH. CONCLUSIONS: Intraocular pressure might increase in NTG eyes following the initial diagnosis. A higher maximum IOP during initial 24-hour pressure curve and the development of DH during follow-up was significantly associated with subsequent IOP elevation in NTG patients.

Adult↗

PubMed2006

Visual field and intraocular pressure asymmetry in the low-pressure glaucoma treatment study.

OBJECTIVE: To explore the relationship between asymmetric baseline intraocular pressure (IOP) and asymmetric visual field (VF) loss in the Low-Pressure Glaucoma Treatment Study. DESIGN: Randomized, multicenter, controlled clinical trial. PARTICIPANTS: Low-pressure glaucoma (LPG) patients 30 years or older were identified. Exclusion criteria included an untreated pressure > 21 mmHg, advanced VF loss, and contraindications to study medications. INTERVENTIONS: A baseline VF was created using the average of 2 reliable Humphrey full-threshold examinations. A baseline diurnal IOP curve was performed without IOP-lowering medication. MAIN OUTCOME MEASURES: Mean diurnal, peak, trough, IOP range (peak - trough), and standard deviation (SD) of IOP measurements, and mean deviation (MD) and corrected pattern SD (CPSD) of VF examinations. RESULTS: One hundred ninety patients were enrolled (mean age, 64.9+/-10.7 years). Mean deviation and CPSD were not correlated with mean, peak, trough, or peak minus trough (P - T) IOP (Ps = 0.2-0.9). Among patients with unilateral VF loss (n = 53 [27.9%]), there were no differences (Ps = 0.3-0.9) in any IOP parameter between the normal VF eye and fellow glaucomatous eyes. Among patients with bilateral VF loss (n = 137 [72.1%]), mean, peak, trough, and P - T IOPs were similar in eyes with a better VF MD compared with eyes with a worse VF MD (Ps = 0.2-0.7). Cross-classified contingency tables demonstrated no relationship (Ps = 0.1-0.3) between IOP and VF MD or CPSD using chi-square analysis. CONCLUSIONS: Intraocular pressure asymmetry is unrelated to VF asymmetry in the Low-Pressure Glaucoma Treatment Study, suggesting an unclear pathogenic relationship between IOP and glaucomatous damage in eyes with LPG.

Adrenergic alpha-Agonists↗

PubMed1987

The effects of forskolin on cyclic AMP, intraocular pressure and aqueous humor formation in rabbits.

Forskolin was used to study cyclic AMP-mediated regulation of aqueous humor dynamics in rabbits. Crystalline forskolin was solubilized in oil and its pharmacological effects were studied both in vitro and following topical ocular administration. In vitro, using cultured corneal epithelial cells, forskolin rapidly stimulated cyclic AMP production and in vivo increased cyclic AMP concentration in the aqueous humor 10-fold following topical administration. The effect of topical forskolin on intraocular pressure and aqueous humor formation was determined in vivo using pneumatonometry and fluorophotometry, respectively. Forskolin caused a prolonged reduction of intraocular pressure and decreased aqueous humor formation. The ability of forskolin to potentiate the ocular hypotensive effect of epinephrine was investigated. Forskolin in combination with epinephrine caused a decrease in intraocular pressure of longer duration than either 0.1% epinephrine or 1% forskolin administered separately. Forskolin caused a small but significant increase in the permeability of the blood-aqueous barrier at the time of maximal intraocular pressure reduction. This effect on the blood-aqueous barrier may explain the inhibitory effect of forskolin on aqueous humor formation.

Animals↗

PubMed1977

[Variations of intraocular pressure induced by psychological stress (author's transl)].

Peculiar psychic reactivity of glaucomatous patients detected clinically and widely treated in the literature, has led us to study the behaviour of intraocular pressure in normal and glaucomatous subjects when submitted to various stresses. The data obtained show that prolonged stress increases intraocular pressure in normal subjects, unlike shorter stress which only causes an increase of intraocular pressure in glaucomatous patients. The possible genesis of the phenomenon is discussed.

Adult↗

PubMedDate not supplied

Falsely elevated intraocular pressure due to an abnormally thick cornea in a patient with nevus of Ota.

BACKGROUND: Several ocular complications, including glaucoma and ocular hypertension, have been reported in patients with nevus of Ota. CASE: A 12-year-old boy with nevus of Ota on the left side of his face was referred for further examination of elevated intraocular pressure in his left eye. OBSERVATIONS: Intraocular pressure measured with Goldmann tonometry was 19 mm Hg OD and 25 mm Hg OS. No visual field defects were detected by Goldmann or Humphrey perimetry. With ultrasonic pachymetry, the mean +/- SD of central corneal thickness was 560 +/- 4 microm in the right eye and 652 +/- 9 microm in the left. CONCLUSION: Ophthalmologists should be aware that the abnormally thick cornea of patients with nevus of Ota may produce falsely elevated intraocular pressure readings.

Child↗