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Results for “INTRAOCULAR PRESSURE”

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At least 613 records · Page 34Linked to original sources

PubMed2002

The effect of an eyelid speculum on intraocular pressure measurement in children.

PURPOSE: To assess the effect of a pediatric eyelid speculum on the measurement of intraocular pressure (IOP) in children. DESIGN: Observational case series. METHODS: Intraocular pressure measurements were performed during examination under anesthesia immediately after induction. The measurements were made with and without a pediatric eyelid speculum in place. RESULTS: Intraocular pressure measurements were made in 77 eyes of 45 consecutive children. The mean IOP without the speculum was 16.33 mm Hg in the right eye and 16.55 mm Hg in the left eye. With the lid speculum in place the mean IOP was 20.26 mm Hg in the right eye and 20.05 mm Hg in the left eye (P <.05). CONCLUSIONS: The presence of an eyelid speculum raised IOP an average of 4 mm Hg. This effect should be considered when interpreting IOP measurements in children.

Adolescent↗

PubMed2006

Short-term course of intraocular pressure after intravitreal injection of triamcinolone acetonide.

OBJECTIVE: To describe the natural history of intraocular pressure (IOP) within the first 30 minutes after intravitreal injection of triamcinolone acetonide (TA). DESIGN: Prospective, interventional, consecutive case series. PARTICIPANTS: Thirty-eight consecutive patients who met inclusion and exclusion criteria and underwent intravitreal injection of 0.1 ml (4 mg) of TA were studied. METHODS: Intraocular pressure was measured by Goldmann applanation tonometry at baseline; immediately after injection; and at 2, 5, 10, 20, and 30 minutes after injection. MAIN OUTCOME MEASURES: Intraocular pressure measurements at baseline; immediately after intravitreal injection; and 2, 5, 10, 20, and 30 minutes after injection, and percentage of patients with IOP < or = 24 mmHg at 30 minutes. RESULTS: Patients who did not experience vitreous reflux (30/38 [78.9%]) at the site of injection had a significant initial elevation of IOP that rapidly normalized. Patients who experienced vitreous reflux (8/38 [21.1%]) at the site of injection had either no change in IOP or a small drop in IOP that rapidly normalized. The IOP measured in millimeters of mercury immediately after injection (45.9 [no reflux], 12.6 [reflux]), 2 minutes after injection (39.9 [no reflux], 13.5 [reflux]), 5 minutes after injection (33.3 [no reflux], 13.8 [reflux]), 10 minutes after injection (26.4 [no reflux], 15.1 [reflux]), and 20 minutes after injection (21.8 [no reflux], 15.0 [reflux]) showed a statistically significant difference between the 2 groups. The difference in IOP between the 2 groups was not significant at baseline or 30 minutes after injection. At 30 minutes, 90% (95% confidence interval, 85.8%-95.2%) of patients without vitreous reflux had an IOP < 24 mmHg. CONCLUSIONS: Patients undergoing intravitreal injection of TA with no vitreous reflux have a risk of short-term elevation of IOP that rapidly normalizes over 30 minutes. In patients with vitreous reflux after the injection, the IOP declines immediately after injection and rapidly normalizes over 10 minutes.

Aged↗

PubMed1997

Ultrasound biomicroscopic findings in humans with shallow anterior chamber and increased intraocular pressure after the prone provocation test.

PURPOSE: To investigate ultrasound biomicroscopic findings in human eyes with shallow anterior chamber and risk of anterior chamber angle-closure glaucoma after the prone provocation test. METHODS: A total of 32 consecutive patients (64 eyes) with bilateral shallow anterior chamber who were at risk for primary angle-closure glaucoma underwent the prone provocation test in a lit room. Before and immediately after measurement of intraocular pressure in this test, high-frequency ultrasound biomicroscopy was performed in the horizontal and vertical directions, and the chamber angle views were recorded at the 3-, 6-, 9-, and 12-o'clock positions. RESULTS: Ten eyes of six patients exhibited an increase in intraocular pressure of 8 mm Hg or more, a positive response, with the remainder showing a negative response to the test. In the eyes with a positive response to the test, the profile of the iris showed a markedly convex shape with a large space behind the posterior iris. However, the anterior chamber angle of each eye remained open, even during the high level of intraocular pressure caused by the provocation. CONCLUSIONS: The present results suggest that no angle closure occurs during the initial increase of intraocular pressure after the prone provocation test. Such an initial increase of intraocular pressure was associated with high pressure in the posterior chamber because of the relative pupillary block. A time lag was observed between the high intraocular pressure caused by the pupillary block and the occurrence of angle closure.

Acetazolamide↗

PubMed1999

Comparison of 24-hour intraocular pressure reduction with two dosing regimens of latanoprost and timolol maleate in patients with primary open-angle glaucoma.

PURPOSE: To compare the 24-hour diurnal ocular hypotensive efficacy of two dosing regimens of latanoprost, once daily (8 AM or 10 PM), vs timolol maleate, twice daily. METHODS: We measured six diurnal intraocular pressure curves (6 AM, 10 AM, 2 PM, 6 PM, 10 PM, and 2 AM) in one randomly selected eye of 34 Greek patients newly diagnosed with primary open-angle glaucoma. The first diurnal curve was an untreated baseline. Patients began taking timolol 0.5%, twice daily, for 2 months. Patients were randomly assigned to latanoprost 0.005% given at 8 AM or 10 PM for 1 month and then changed to the other dosing regimen for 1 month. A diurnal curve was performed after each dosing period. RESULTS: The baseline diurnal pressure for all 34 subjects was 23.1 +/- 3.7 mm Hg. The average intraocular pressures at 6 AM for patients who were given latanoprost in the evening (17.9 +/- 2.9 mm Hg) was statistically lower than that in patients given timolol solution (20.1 +/- 2.5 mm Hg, P = .003); however, patients who were given timolol demonstrated a similar diurnal intraocular pressure (19.1 +/- 2.8 mm Hg) to both morning (18.8 +/- 3.7 mm Hg) and evening doses (18.8 +/- 3.6 mm Hg) of latanoprost (P =.329). When the two latanoprost dosages were compared directly, evening administration provided a statistically lower intraocular pressure at 10 AM (P = .0001) and morning administration at 10 PM (P = .0001). This study had an 80% power to exclude a 1.2-mm Hg difference between groups. CONCLUSIONS: This study indicates that in a small population, both latanoprost and timolol are effective in lowering intraocular pressure throughout a 24-hour period; however, latanoprost is most effective in the 12-hour to 24-hour period after administration.

Adrenergic beta-Antagonists↗

PubMed2006

Validation of the Barraquer tonometer for high intraocular pressure estimation.

PURPOSE: To compare the pneumatonometer and the Tono-Pen XL in a closed ex-vivo system in human eye bank eyes at high intraocular pressures (IOP) and evaluate the validity of high IOP measurements with the Barraquer tonometer. METHODS: Intraocular pressure was monitored by cannulation of the anterior chamber and vitreous cavity in eight human cadaver eyes (mean donor age: 77.3 +/- 4.9 years, range: 72 to 84 years). Intraocular pressure measurements were taken at 50, 65, and 90 mmHg with the Tono-Pen XL and pneumatonometer. Intraocular pressure was raised to 110 mmHg and then the eyes were deflated slowly until they reached 50 mmHg. Pressure readings with the Barraquer tonometer were recorded when the corneal tonometer interface reached the inner and outer rings. RESULTS: The Tono-Pen XL underestimated IOP, a tendency that was more evident at higher IOP In contrast, the pneumatonometer was more accurate and reliable at IOP of 50 and 65 mmHg but its readings underestimated IOP at 90 mmHg. The Barraquer tonometer used in this experiment accurately estimated high IOP A variability of 5.9 mmHg and 5.8 mmHg were recorded for the inner and outer ring, respectively. CONCLUSIONS: The Tono-pen XL is an inadequate instrument to assess pressures normally encountered during LASIK flap creation in an ex vivo model using human cadaver eyes. The pneumatonometer and the Barraquer tonometer are accurate instruments at high IOP; however, the pneumatonometer underestimated pressures around 90 mmHg.

Aged↗

PubMed2001

Effects of 2% ibopamine on pupil, refraction, anterior segment anatomy and intraocular pressure.

The aim of the study was to determine the effects of a dopaminergic drug, 2% ibopamine, on the pupil, intraocular pressure and other ocular and ultrasound biometric variables. Thirty healthy subjects and 15 patients with primary open-angle glaucoma, aged from 40 to 78 years (mean age: 59.2 +/- 11), were included in two prospective open controlled trials. In the first, the mydriatic effect of 2% ibopamine and its inhibition and reversibility were evaluated in 15 healthy subjects using the alpha1-adrenergic drug, 0.5% dapiprazole. In the second, refraction, visual acuity, pupil diameter, intraocular pressure and 5 A-scan ultrasound biometric variables were evaluated in 15 healthy subjects and in 15 glaucoma patients. As early as forty min after administration of 2% ibopamine, a marked mydriatic effect (7.3 vs 3.9 mm; P < 0.0001), which was completely inhibited or reversed by 0.5% dapiprazole, was detected. The drug induced no changes in refraction, visual acuity or A-scan ultrasound biometric variables in any of the subjects examined. In healthy subjects, the intraocular pressure values were not changed to a statistically significant extent (13.8 vs 14.8 mm Hg; P = 0.668), whereas a slight, though significant, hypertensive effect (24 vs 22.2 mm Hg; P = 0.002) was observed in the glaucoma patients. The study confirms the intense mydriatic effect of 2% ibopamine with no changes in refraction, visual acuity or A-scan ultrasound biometric variables. The drug has no effect on intraocular pressure in healthy subjects, but induces a significant hypertensive effect in patients with initial glaucoma. This characteristic could be used for early diagnosis of primary open-angle glaucoma.

Adrenergic alpha-Antagonists↗

PubMed1999

Corneal thickness, intraocular pressure, and optical corneal diameter in Rocky Mountain Horses with cornea globosa or clinically normal corneas.

OBJECTIVE: To compare corneal thickness, intraocular pressure, and optical corneal diameter in Rocky Mountain Horses with cornea globosa and those with clinically normal corneas. ANIMALS: 129 Rocky Mountain Horses. PROCEDURE: Ultrasonic pachymetry was used to measure corneal thickness. Applanation tonometry was used to measure intraocular pressure. A Jameson caliper was used to measure optical corneal diameter. RESULTS: The central and temporal peripheral portions of the cornea were significantly thicker in horses with cornea globosa than in horses with clinically normal corneas, but corneal thicknesses in the dorsal, ventral, and medial peripheral portions of the cornea were not significantly different between groups. There were no differences in corneal thickness between male and female horses or between right and left eyes. However, there was a positive correlation between age and corneal thickness. Intraocular pressure was not significantly different between horses with cornea globosa and those with clinically normal corneas, or between right and left eyes, or male and female horses. Optical corneal diameter for horses with cornea globosa was not significantly different from diameter for horses with clinically normal corneas, but optical corneal diameter was positively correlated with age. CONCLUSIONS AND CLINICAL RELEVANCE: Cornea globosa in Rocky Mountain Horses is not associated with increased intraocular pressure. Corneal thickness and optical corneal diameter increase with age in Rocky Mountain Horses.

Aging↗

PubMed2003

Lidocaine: the optimal timing of intravenous administration in attenuation of increase of intraocular pressure during tracheal intubation.

BACKGROUND: This study was designed to examine the optimal timing of intravenous lidocaine in attenuation of increase of intraocular pressure in response to laryngoscopy and tracheal intubation during induction of anesthesia. METHODS: One hundred and thirty five adult patients of ASA class I, aged between 20-35 years, undergoing surgical procedures irrelevant to ophthalmology were enrolled for study. Patients were randomly assigned to one of five groups. In group II, III, IV and V the patients received intravenous injection of lidocaine (2 mg/kg), 1, 3, 5, 10 min before tracheal intubation, respectively. Group I in which patients did not receive lidocaine served as the control group. RESULTS: In patients of groups I, IV and V, the intraocular pressure increased significantly after intubation, whereas in those of groups II and III, the intraocular pressure did not. All patients in the five groups showed concomitantly a surge of blood pressure, but the magnitude of increase was smallest in group III in comparison with the other groups. The values of systolic and diastolic pressures 1 min after intubation were significantly less in groups III and IV than in the control group. CONCLUSIONS: In healthy patients aged between 20 and 35 the most optimal time of administration of intravenous lidocaine to attenuate the increase of intraocular pressure seemed to be the space between 1 to 3 min before laryngoscopy and tracheal intubation.

Adult↗

PubMed1976

The dynamics and location of axonal transport blockade by acute intraocular pressure elevation in primate optic nerve.

Axonal transport in primate optic nerve axons was studied by autoradiography, scintillation counting, and electron microscopy under conditions of short-term intraocular pressure elevation. With elevation of intraocular pressure to 30 mm. Hg below mean arterial blood pressure, blockage of transport was detected within 2 hours by autoradiography and within 1 hour by electron microscopy. The earliest buildup of radioactively labeled protein and ultrastructurally visible cellular organelles was within the scleral lamina cribrosa. The degree of blockage, judged by amount of label buildup, increased with time. Some transported material traversed the lamina cribrosa despite pressure elevation at the level tested. Reversal of transport blockade occurred rapidly after normalization of intraocular pressure.

Acute Disease↗

PubMed1996

Comparison of anterior chamber infusates on the intraocular pressure of intact rat eyes.

1. Infusions of balanced salt solutions (BSS) into the eye often cause a delayed, gradual increase in intraocular pressure or outflow facility, known as the "washout" effect. The reason(s) is occult, especially at low input rates when drainage mechanisms are not overloaded by excessive volume input. However, direct, quantitative comparisons of BSSs used in ocular research have been reported infrequently. 2. We compared the effects of three BSSs on intraocular pressure and the estimated resistance to drainage after a 1-hr, low-volume infusion into the anterior chambers of the eyes of anesthetized rats. 3. The BSSs tested raised intraocular pressure (P < 0.05) after a 20-40-min delay, and the highest IOPs occurred at 1 hr. Recovery of intraocular pressure to baseline only occurred with one BSS (Dulbecco). 4. Fitting the ascending and descending portions of the mean pressure curves to an exponential revealed differences among the infusates. The Dulbecco solution resulted in minimal changes in time constant, gain, and offset during the ascending and descending periods. 5. The data obtained show that different BSSs yield pressure curves that appear grossly similar, even though there were large differences in composition and osmolality. However, the underlying changes in ocular dynamics were not identical. Thus, it may be prudent to test more than one solvent to study "washout," or to deliver drugs directly into the anterior chamber.

Animals↗

PubMed1985

Interaction of timolol and caffeine on intraocular pressure.

The clinical interaction of 0.5% timolol maleate and 400 mg of oral caffeine on the intraocular pressure of 20 normotensive volunteers was studied. Caffeine administration did not significantly alter the reduction in intraocular pressure in timolol treated eyes. An antagonism, however, was observed in the fellow timolol untreated eyes with caffeine. The crossover reduction in intraocular pressure noted in the control group was significantly depressed in the caffeine group. A proposed mechanism for these observations is discussed.

Adult↗

PubMed1979

Consequences of eyelid squeezing on intraocular pressure.

We investigated the effect of a forcible eyelid squeeze (two-second squeeze and two-second rest) over one minute, on intraocular pressure in volunteer groups of normal volunteers, ocular hypertensive and glaucoma patients, and those with a family history of glaucoma. The normal volunteers fell into two groups: responders and nonresonders, with the responders showing about a 2-mm Hg decrease and the nonresponders a small increase in intraocular pressure. It was possible to arrange the groups into an order dependent upon the change in intraocular pressure induced by eyelid squeezing; normal responders (-1.98 mm Hg), family history of glaucoma (-0.48 mm Hg), ocular hypertensive patients (-0.07 mm Hg), normal nonresponders (+ 0.04 mm Hg) and glaucoma patients (taking medication) (+ 0.25 mm Hg). Correlation of disease entity with other ocular factors such as intraocular pressure and total outflow facility was poor.

Adolescent↗

PubMed2001

Caffeine and intraocular pressure in a Nigerian population.

PURPOSE: Caffeine is widely consumed as kola nuts and in other products in sub-Saharan Africa. We examined the acute effect of caffeine on the intraocular pressures of healthy Nigerian volunteers between the ages of 20 and 27 years. METHODS: Intraocular pressure and blood pressure were measured 0, 30, 60, and 90 minutes after the ingestion of coffee by two groups of participants, namely the experimental (caffeinated coffee) and control (decaffeinated coffee) groups. RESULTS: The result showed that ingested caffeine increases intraocular pressure and that the elevation, though variable across patients, is sustained for several minutes. The mean increase across patients rises monotonically with the postingestion time and by almost 4 mm Hg. There was also a corresponding increase in systolic and diastolic blood pressure of the caffeinated group. There was relatively no change in intraocular pressure or blood pressure with time in the control group. The difference between both groups was statistically significant (P < 0.05). CONCLUSIONS: The results suggest the need for more glaucoma screenings and proper patient education, particularly in Nigerian populations in which the consumption of caffeine, contained in kola nuts and in other raw and processed products, is endemic and long-term.

Adult↗

PubMed1992

[Changes in intraocular pressure during hemodialysis and hemofiltration].

The authors compare changes of intraocular pressure during haemodialysis and haemofiltration in six patients. The measurements were made with the patients in a sitting position, using an applanation tonometer according to Perkins, during both operations every hour. A rise to 25 torr was recorded in one patient repeatedly during haemofiltration in both eyes one hour after the blood pressure had risen to 220/120 and 210/110. In the other patients the variations of the intraocular pressure were within the physiological range. Based on data in the literature the authors recommend the use of haemofiltration in patients with glaucoma and after eye surgery.

Adult↗

PubMed1985

[Modification of retinal hemodynamics by induced changes in intraocular pressure: a videoangiographic study].

This study used videoangiography to observe the effect of artificially produced rises in pressures in the eye on the haemodynamics of the retinal vessels. The intraocular pressure was increased with Müller's ophthalmodynamometer in stages of 10 mm Hg. A demonstrable effect upon the arterial and early venous times as well as the arm-retina time appeared. A constant rise in pressure appeared in the acute experiment: here the circulatory times more than doubled when intraocular pressure rose from under 20 mm Hg to 40 mm Hg. Above 50 mm Hg a further, statistically highly significant increase in the circulatory times of the eye became evident. The retinal vessels were obliterated in the rule at intraocular pressures above 50 mm Hg. When the data on changes in retinal circulation acquired by videoangiography are compared with the data on blood volume flow-through reached with microspheres, both methods reveal a good correlation. This shows that the determination of circulatory times in the eye is also a source of information on blood volume flow.

Adult↗

PubMed1979

Effect of pancuronium on intraocular pressure changes induced by succinylcholine.

The study was undertaken to evaluate the influence of pretreatment with a small dose of pancuronium on intraocular pressure changes associated with administration of succinylcholine and tracheal intubation. Thirty patients divided into control and study groups were anaesthetized with sodium thiopentone (3-5 mg mg.kg-1) and intubation with the aid of succinylcholine (1 mg.kg-1). The control group received saline pretreatment while the study group received pancuronium 1 mg three minutes before succinylcholine. Anaesthesia was maintained with nitrous oxide and oxygen (70:30). A Schiotz tonometer was used to measure intraocular pressure before induction of anaesthesia, one minute after succinylcholine and immediately after intubation. Patients in the control group demonstrated significant elevation of intraocular pressure at one minute after succinylcholine and immediately after intubation, while the study group showed no significant change at the same observation periods. These findings indicate that pretreatment with pancuronium 1 mg three minutes before succinylcholine may be beneficial in patients with high intraocular pressure and penetrating injuries of the eye.

Adolescent↗

PubMed1997

Mechanisms of acute intraocular pressure increases after phacoemulsification lens extraction in dogs.

OBJECTIVE: To investigate the mechanisms by which intraocular pressure (IOP) increases acutely after phacoemulsification (PE) lens extraction in clinically normal dogs. ANIMALS: 24 young adult dogs. PROCEDURE: Intraocular pressure was monitored for up to 24 hours after unilateral intercapsular PE in 17 clinically normal, adult dogs. In 8 of these dogs, use of 2% hydroxypropyl methylcellulose (HPMC) aided capsulorhexis. Mean volume of irrigation, PE time, and power were constant between groups. After surgery, dogs were randomized then euthanatized, and eyes were examined grossly and histologically at 0 (n = 4), 3 (n = 7), and 24 hours (n = 6) after PE. Seven additional dogs underwent anterior chamber decompression alone (n = 4) or served as morphologic controls (n = 3). RESULTS: Intraocular pressure peaked by postoperative hour 3 at 49.9 +/- 5.0 mm of Hg and normalized by 24 hours. Use of HPMC did not affect the peak or duration of IOP increase. Blood refluxed into the collecting channels and corneoscleral trabecular meshwork in operated eyes. Computer-aided morphologic analysis indicated significant (P < 0.001) reduction in ciliary cleft cross-sectional surface area and width immediately after PE, but not after anterior chamber decompression alone. Cleft collapse was significantly (P < 0.02) greater at 24 than at 3 hours, despite return of IOP to control values by 24 hours. Plasmoid aqueous also was found in the meshwork. CONCLUSIONS AND CLINICAL RELEVANCE: Sudden, large increases in IOP with few overt clinical signs may occur immediately after lens extraction in dogs. Such increases risk compromising the corneal incision and may damage the optic nerve, thereby complicating lens extraction. Structural alterations in the trabecular meshwork persist after IOP has normalized in 24 hours and may contribute to genesis of glaucoma in the late postoperative period.

Analysis of Variance↗

PubMed1988

Intraocular pressure reduction prior to retrobulbar injection of anesthetic.

Following the retrobulbar injection of anesthetic, the application of a mechanical device to lower the intraocular pressure will produce a rise in intraocular pressure that may be sufficient to compromise ocular perfusion. To increase the margin of safety for ischemic damage, a mechanical means of intraocular pressure reduction (Superpinkie) was applied prior to, rather than following, the retrobulbar injection of anesthetic. The study group consisting of 20 patients receiving the compression-injection sequence had a mean preoperative pressure of 4.70 mm Hg, while a control group of 20 patients receiving the injection-compression sequence had a mean preoperative pressure of 2.25 mm Hg. The proposed compression-injection method was well tolerated by the patients and attained surgically adequate anesthesia, akinesia, and ocular opening pressures. In selective cases, the compression-injection technique for the delivery of retrobulbar anesthesia may offer a means of better maintaining ocular perfusion and thereby lessening the risk of vascular compromise.

Anesthesia, Local↗