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Results for “INTRAOCULAR PRESSURE”

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At least 577 records · Page 32Linked to original sources

PubMed2001

The effect of vitrectomy with silicone oil tamponade on intraocular pressure and anterior chamber morphology.

We measured the tamponading effect of silicone oil, saline and air after vitrectomy, on intraocular pressure and aqueous humor outflow in 85 patients with highly proliferative retina and vitreous changes. Silicone oil as retinal tamponading agent after vitrectomy was used in 45 patients, and saline or air in 39 patients. The mean intraocular pressure measured at one month after treatment was greatly elevated in patients with silicone oil tamponade as compared to those with saline or air tamponade. At 6 and 12 months examinations, mean intraocular pressures were compared in these two groups of patients. Gonioscopy revealed silicone oil emulsification and presence of emulsified bubbles in the anterior chamber in 22.22% of patients, and narrowing of the chamber angle in several patients with silicone oil tamponade. Intraocular pressure elevation following vitrectomy with silicone oil tamponade was found to be of transient rather than permanent nature, since it regressed after silicone oil removal. This transient elevation was due to silicone oil tendency to emulsify. Silicone oil bubbles changed the morphology of the anterior chamber angle and fine trabecular structures by creating a barrier to aqueous humor outflow.

Air↗

PubMed1975

The circadian rhythm of the intraocular pressure in the New Zealand White rabbit.

Most physiologic functions in man as well as in animals have been shown to have a circadian (approximately 24 hour) rhythm. It has been found in both the normal and glaucomatous human eye that the intraocular pressure, which is one of these circadian functions, varies considerably over a 24-hour period. Because of the extensive use of the rabbit in glaucoma research, a detailed study of the intraocular pressure over a 24-hour period was undertaken. Using hourly applanation tonometry for 25 consecutive measurements in ten New Zealand White rabbits (20 eyes), a circadian rhythm of the rabbit intraocular pressure was found. The pressures were lowest at night and rose to their highest values during the day. In addition, the data suggest that the maximum intraocular pressure may be biphasic with maximum values occurring between 0800 and 1100 and 1600 and 1900. Therefore, studies involving the New Zealand White rabbit must take into consideration these 24-hour pressure changes when intraocular pressure measurements are made.

Animals↗

PubMed1985

Argon laser trabeculoplasty as a means of decreasing intraocular pressure from "normal" levels in glaucomatous eyes.

We conducted a retrospective study of 67 patients (85 eyes) with severe glaucoma to determine whether argon laser trabeculoplasty could reduce intraocular pressures below the "normal" range. All patients had initial intraocular pressures of less than or equal to 19 mm Hg. Success was defined as a decrease in intraocular pressure of at least 20%, no increase in medications, stable visual field, and no subsequent glaucoma surgery. After an average follow-up period of 30 months, treatment was successful in 31 cases. One half of the failures occurred by six months and 11 failures (30%) occurred after 12 months. Sixteen patients were able to decrease their medications. Two patients achieved intraocular pressures between 6 and 9 mm Hg and 20 between 10 and 12 mm Hg.

Adult↗

PubMed1977

Effect of delta-9-tetrahydrocannabinol on intraocular pressure in humans.

As early as 1971, it was noted that smoking marijuana lowered intraocular pressure. In this study one of the active components of marijuana, delta-9-tetrahydrocannabinol, was given intravenously to ten subjects with normal intraocular pressures. Two strengths were used--0.022 mg/kg of body weight and 0.044 mg/kg of body weight. Intraocular pressure was found to decrease as much as 51% of baseline normal with an average decrease of 37%. Heart rate increased in a range of 22% and 65% of the resting pulse. Respiratory rate was not affected. No analgesic properties were demonstrated by either cutaneous or periosteal stimulation. Anxiety levels were increased by delta-9-tetrahydrocannabinol over placebo and diazepam (Valium). The mechanism of action is still uncertain but it is believed by some workers to be similar to that of a beta-adrenergic stimulator.

Analgesia↗

PubMed1984

Effects of timolol on intraocular pressure following ocular adrenergic denervation.

The effects of timolol on the elevation of intraocular pressure induced by orogastric water-loading were studied in conscious pigmented rabbits which had undergone unilateral, superior cervical ganglionectomy. Each rabbit was studied without timolol treatment and with unilateral 2% timolol treatment, either to the innervated eye or to the denervated eye, 90 min before water-loading. Timolol, applied to the innervated eye, significantly reduced the elevation of intraocular pressure in that eye, but not in the fellow eye. Timolol, applied to the denervated eye, did not affect the elevated intraocular pressure in either the denervated or the fellow eye. These results demonstrate that ocular adrenergic innervation participates in the mechanism of ocular hypotensive action of timolol in water-loaded pigmented rabbits.

Animals↗

PubMed2001

[Influence of cornea thickness changes after refractive surgery on intraocular pressure measurements].

PURPOSE: Assessment of influence of of the cornea thickness decrease on intraocular pressure (IOP) measurements with Goldmann applanation tonometry in patients after refractive surgery procedures (PRK and LASIK). MATERIAL AND METHODS: 80 eyes in 40 patients (pts) qualified for myopia correction with laser surgery were divided into two groups: in Ist group--20 pts (40 eyes)--PRK procedure was performed and in IInd group--40 eyes (20 pts) LASIK was performed. IOP was measured by Goldmann applanation tonometry. The cornea thickness was assessed in its central region with endothelial microscope with pachymetric facility (Cooper Vision). The eyes were evaluated twice: before and 1 month after the procedure. RESULTS: In all eyes after laser surgery procedures IOP was lower because of the decrease of central cornea thickness. CONCLUSIONS: The central cornea thickness is an important factor influencing intraocular pressure measurements with Goldmann applanation tonometry. Refractive surgery procedures leading to the decrease of central cornea thickness result in lower intraocular pressure measurements in applanation tonometry.

Adult↗

PubMed1989

Intraocular pressure as an index of ocular injury in orbital fractures.

An improved method of screening for ocular injuries in patients sustaining orbital fractures is proposed. We performed a retrospective study of 107 patients who sustained orbital fractures. Intraocular pressures were measured on presentation in 17 patients and were found to be elevated on the side of the injury in eight patients, five (63%) of whom had significant ocular injury. No patient with normal intraocular pressure was found to have an ocular injury. In a prospective study, the intraocular pressures of 30 patients sustaining orbital fractures were measured. Twelve patients (40%) had normal (less than 22 mm Hg) and bilaterally symmetric (less than 3 mm Hg difference) intraocular pressures. One (8%) of these patients sustained ocular injury. In contrast, 18 patients (60%) had either an elevated intraocular pressure (greater than 22 mm Hg) or a difference between eyes of greater than or equal to 3 mm Hg. Eleven (61%) of these patients were found to have sustained an ocular injury. We conclude that intraocular hypertension or significant interocular pressure differences should alert the physician to a potential ocular injury.

Adolescent↗

PubMed1988

Intraocular pressure response to topical dexamethasone as a predictor for the development of primary open-angle glaucoma.

In a retrospective study we reviewed the records of 788 subjects who had been corticosteroid tested with 0.1% dexamethasone four times daily to one eye for six weeks. All subjects had normal kinetic visual fields and optic nerve heads in both eyes at the time of testing and were followed up for a minimum of five years. Some subjects had normal baseline intraocular pressures whereas others were considered to have ocular hypertension. Of 276 individuals who were high corticosteroid responders (intraocular pressure greater than 31 mm Hg during dexamethasone administration), 36 (13.0%) developed glaucomatous visual field loss during the follow-up period. Only nine of 261 individuals (3.4%) who were intermediate responders (intraocular pressure 20 to 31 mm Hg during dexamethasone administration) and none of 251 individuals who were low responders (intraocular pressure less than 20 mm Hg during dexamethasone administration) developed glaucomatous visual field loss. However, the ability of the intraocular pressure response to dexamethasone to predict the development of glaucomatous visual field loss was not as good as the predictive power of a multivariate model that included patient age, race, baseline intraocular pressure, baseline outflow facility, baseline cup/disk ratio, and systemic hypertension.

Adult↗

PubMed2002

Sufentanil or clonidine for blunting the increase in intraocular pressure during rapid-sequence induction.

BACKGROUND AND OBJECTIVE: The aim was to determine if the intravenous administration of sufentanil or clonidine before the induction of anaesthesia could obtund the increase of intraocular pressure associated with rapid-sequence induction. METHODS: Thirty-two ASA I-II patients with no history of eye illness scheduled for elective non-ophthalmic surgery were randomly assigned to receive either sufentanil 0.05 microg kg(-1) i.v. (Group A, n = 15) or clonidine 2 microg kg(-1) i.v. (Group B, n = 17) prior to induction. General anaesthesia was induced with thiopental (5 mg kg(-1)) followed by succinylcholine 1 mg kg(-1) to facilitate tracheal intubation. The general anaesthetic technique was standardized in both groups. Intraocular pressure was measured using the Schioetz tonometer just before the succinylcholine administration (t0), just before tracheal intubation (t1) and immediately after intubation (t2). Mean arterial pressure and heart rate were recorded at the same time intervals. RESULTS: Intraocular pressures were similar in both groups at t0, but the sufentanil group had significantly lower values compared with the clonidine group just before (t1) and immediately after tracheal intubation (t2). CONCLUSIONS: Sufentanil is effective in blunting the increase in intraocular pressure caused by rapid-sequence induction with succinylcholine, while clonidine did not seem to have any effect in intraocular pressures just before (t1) and just after (t2) intubation.

Adrenergic alpha-Agonists↗

PubMed1987

Epidemiology of intraocular pressure in a population screened for glaucoma.

This study evaluated the association between intraocular pressure and various sociodemographic characteristics, ocular findings, and cardiovascular risk factors in a population screened for glaucoma. A total of 2594 subjects older than 40 years residing in three urban areas of southern Israel participated. Of those screened 6.1% had a raised intraocular pressure (IOP greater than or equal to 21). The mean IOP increased with age, was higher among persons born in Africa or Asia than those born in Europe or America, higher among myopes than hypermetropes and among those with an enlarged cup-disc ratio (CDR). Analysis of variance tests indicated that refractive status, CDR, age, country of birth, and diabetes were each independently associated with IOP. In addition, associations between raised intraocular pressure and age, country of birth, myopia, CDR, diabetes, and glaucoma in the family were found.

Adult↗

PubMedDate not supplied

Intraocular pressure change after neodymium:YAG capsulotomy.

PURPOSE: To study intraocular pressure (IOP) after neodymium:YAG (Nd:YAG) laser posterior capsulotomy in eyes that had phacoemulsification, anterior continuous curvilinear capsulotomy, in-the-bag intraocular lens (IOL) implantation, and no apparent communication between the aqueous and vitreous compartments after the Nd:YAG capsulotomy. SETTING: Northwest Kansas Eye Clinic, Hays, Kansas. METHODS: This study comprised 101 eyes. All patients received one drop of apraclonidine hydrochloride 0.5% (lopidine) 30 to 60 minutes before and then after Nd:YAG capsulotomy, intraocular pressure was measured preoperatively before administration of lopidine and at 1 to 3 and 24 hours, 1 week, and 1 month postoperatively. RESULTS: Within 24 hours after the Nd:YAG capsulotomy, no significant IOP elevations occurred. Although there was one case of modest IOP elevation at 1 week postcapsulotomy, none was seen at 4 weeks. There was no relation between change in IOP and number of laser pulses, energy per pulse, or total energy. CONCLUSION: The results indicate that lack of communication between the aqueous and vitreous compartments with an intact capsulorhexis over the lens optic rim prevented obstruction of the trabecular network by cellular debris or vitreous. This, coupled with the reduction in aqueous formation by lopidine, prevented significant IOP elevation. In patients meeting the study criteria, routine IOP measurements 1 to 3 hours and 1 day after capsulotomy may not be necessary.

Aged↗

PubMed2000

Effects of 0.005% latanoprost solution on intraocular pressure in healthy dogs and cats.

OBJECTIVE: To evaluate effects of daily topical ocular administration of latanoprost solution on intraocular pressure (IOP) in healthy cats and dogs. ANIMALS: 9 domestic shorthair cats and 14 dogs. PROCEDURE: Latanoprost solution (0.005%) was administered topically to 1 eye (treated) and vehicle to the other eye (control) of all animals once daily in the morning for 8 days. Intraocular pressure was measured twice daily for the 5 days preceding treatment, and IOP, pupillary diameter, conjunctival hyperemia, and blepharospasm were measured 0, 1, 6, and 12 hours after the first 4 treatments and 0 and 12 hours after the final 4 treatments. Measurements continued twice a day for 5 days after treatment was discontinued. Aqueous flare was measured once daily during and for 5 days after the treatment period. RESULTS: Intraocular pressure and pupillary diameter were significantly decreased in the treated eye of dogs, compared with the control eye. Mild conjunctival hyperemia was also detected, but severity did not differ significantly between eyes. Blepharospasm and aqueous flare were not detected in either eye. Intraocular pressure in cats was not significantly affected by treatment with latanoprost. However, pupillary diameter was significantly decreased in the treated eye, compared with the control eye. Conjunctival hyperemia, aqueous flare, and blepharospasm were not detected in either eye. CONCLUSIONS AND CLINICAL RELEVANCE: Once-daily topical ocular administration of latanoprost solution (0.005%) reduced IOP in healthy dogs without inducing adverse effects but did not affect IOP in healthy cats. Latanoprost may be useful for treating glaucoma in dogs.

Administration, Topical↗

PubMed1992

Dexmedetomidine-induced ocular hypotension in rabbits with normal or elevated intraocular pressures.

This study covered the ocular hypotensive effects of the stereoisomers of the alpha 2-adrenoceptor agonist medetomidine. The dextro-isomer, dexmedetomidine, is known from pharmacologic experiments to be a specific, potent, and selective full agonist at alpha 2-adrenoceptors, whereas the levo-enantiomer seems to be almost inactive. Thus, the levo-isomer (0.5 mg/ml, 25 microliters) had no significant effect on intraocular pressure. After unilateral topical administration, dexmedetomidine (0.5 mg/ml, 25 microliters) lowered intraocular pressure bilaterally in normal rabbits and in rabbits with intraocular pressure elevated after laser irradiation of the pigmented trabecular band of the anterior chamber angle. In the treated (ipsilateral) eye of normal rabbits, a maximum decrease of 4.6 +/- 0.6 mmHg was observed at 2 hr post treatment. In the contralateral eye, the maximum decrease was 4.1 +/- 0.5 mmHg at 1 hr after treatment. In rabbits with laser-induced elevation of intraocular pressure, the maximum decrease in treated hypertensive eyes was 13.5 +/- 0.3 mmHg 1 hr after dexmedetomidine administration. These results indicate that the selective alpha 2-adrenoceptor agonist, dexmedetomidine, is a potent and effective drug for decreasing intraocular pressure in rabbits.

Administration, Topical↗

PubMedDate not supplied

Intraocular pressure: new perspectives.

Reevaluation of normal intraocular pressure (IOP) was attempted to investigate possible background factors that contribute to variations in IOP. It is well known that IOP increases with age among Western populations, while in the Japanese IOP has been confirmed to decrease with aging. Such paradoxical results can not be reasonably explained without considering systemic conditions rather than local factors peculiar to different races. Accumulated evidence indicates that IOP is positively correlated with blood pressure, obesity and other cardiac risk variables. Incorporation of these factors by stratifying the sample may provide the baseline IOP in those who are different in systemic conditions.

Age Factors↗

PubMed1978

Correlation of aqueous humor ascorbate with intraocular pressure and outflow facility in hereditary buphthalmic rabbits.

The hypotensive effect of ascorbate on intraocular pressure has been reported following topical application, oral administration, or anterior chamber infusion in animals. The present report describes the correlation of aqueous humor ascorbate concentration with intraocular pressure as well as outflow facility in vivo. Low aqueous ascorbate level was seen in buphthalmic eyes with high intraocular pressure and low outflow facility. The opposite correlation was observed in normal eyes. Ascorbate concentration in the anterior chamber of the rabbit eye is apparently related to the alteration of outflow facility and the movement of fluid in the anterior chamber.

Animals↗

PubMed1975

Influence of body position on the intraocular pressure of normal and glaucomatous eyes.

In 77 normal and 65 glaucomatous eyes the influence of body position on the intraocular pressure was studied, using the pneumatonograph. The pressure increment when changing from the seated to the supine position averaged 2.9 mm Hg in normal eyes and 3.9 mm Hg in glaucomatous eyes. The pressure increase occurred immediately upon lying down and was reversible after returning to the seated position. Comparative measurements with the Goldman tonometer in the seated position showed good agreement with the results obtained by the pneumatonograph. The Schiotz tonometer did not reliably reveal the true supine intraocular pressure. The postural response (seated to supine) showed considerable variation in individual normal and glaucomatous eyes, and it did not correlate consistently with the intraocular pressure in the seated position. It should be taken into account that the results in the glaucomatous eyes were obtained while the patients were on glaucoma medication. In a series of six lowtension glaucomatous eyes the postural response was significant as a probable pathogenetic factor in that disease, because the intraocular pressure could rise from a normal to a glaucomatous level upon changing from the seated to the supine position.

Adult↗

PubMed1980

Effect of hypercapnea and hyperventilation on human intraocular pressure general anaesthesia following acetazolamide administration.

The changes in intraocular pressure due to blood pH, PCO2, and PO2 alterations induced by hyperventilation and hypercapnea in man undergoing routine general anaesthesia were studied. It was shown that hypercapnea produces elevation of intraocular pressure, while hyperventilation lowers it. Acetazolamide pretreatment did not alter these IOP responses to PCO2, PO2, and blood pH changes.

Acetazolamide↗

PubMed2000

[Evaluation of the anterior chamber depth and intraocular pressure before and after the operation of cataract in glaucoma patients].

The aim of the paper was to assess the effect of surgical extracapsular cataract extraction with implantation of posterior chamber lens on the normalisation of intraocular pressure in eyes with glaucoma. The relationship between the preoperative depth of the anterior chamber and the postoperative normalisation of intraocular pressure was also investigated. The study was carried out on 138 eyes with cataract and glaucoma. Simple open-angle glaucoma was found in 37 eyes (26.8%), simple closing-angle glaucoma in 67 eyes (48.6%) and glaucoma with the pseudoexfoliation syndrome in 34 eyes (24.6%). Before the operation the intraocular pressure in patients ranged from 21 to 32 mm Hg. The depth of the anterior chamber was measured by means of ultrasound method. Intraocular pressure was checked for 9 months after the operation. In patients with open-angle glaucoma the depth of the anterior chamber ranged from 3.1 to 4.0 mm, in closing-angle glaucoma from 2.4 to 3.2 mm, with glaucoma in pseudoexfoliation syndrome from 3.3 to 4.2 mm. After operation the depth of anterior chamber was from 3.7 to 4.6 mm. Nine months after the operation in 64 patients (46.3%) there was no need for giving pressure reducing drugs. The highest percentage of patients who did not require treatment (73.2%) was among eyes with closing-angle glaucoma with the smallest depth of the anterior chamber before operation. It seems that the measurement of the anterior chamber depth before the operation in patients with cataract and closing-angle glaucoma may be only the indication whether the cataract extraction with the implant of the lens is sufficient to normalize the intraocular pressure.

Anterior Chamber↗