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At least 253 records · Page 14Linked to original sources
PubMed2000

Effect of wind instrument playing on intraocular pressure.

PURPOSE: To evaluate the effect of wind instrument playing on intraocular pressure. METHODS: In a prospective, nonrandomized clinical trial, 24 eyes of 24 wind instrument players with no history of any ocular or systemic disease were evaluated. The musicians were members of Bilkent Academic Symphony Orchestra of Bilkent University in Ankara. A complete eye examination, including best-corrected visual acuity, slit-lamp examination, and fundus examination, was performed. The intraocular pressure was measured before and after a 90-minute rehearsal of a piece by Wagner. All intraocular pressure measurements were carried out by the same researcher using Goldmann applanation tonometry. The difference in intraocular pressure measurements before and after the 90-minute wind instrument-playing performance was analyzed. RESULTS: The mean intraocular pressure was 13.79 +/- 1.93 mm Hg before and 15.12 +/- 2.44 mm Hg after the performance. Wind instrument playing significantly increased the mean intraocular pressure by 9.6% (P = 0.0149). CONCLUSION: These results indicate that wind instrument playing may significantly increase intraocular pressure in healthy patients. The significance of this finding for patients with suspected normal-tension or high-tension glaucoma needs further evaluation.

Adult↗
PubMedDate not supplied

Control of intraocular pressure after trabeculectomy.

Control of intraocular pressure (IOP) is the goal of trabeculectomy, and pursuit of this goal does not end with the completion of the surgical procedure. Proper postoperative management of the trabeculectomy patient requires an understanding of possible events that alter IOP and knowledge of the treatments to control IOP. Recent changes in surgical technique, including the use of antimetabolites, have provided new challenges in the postoperative management of trabeculectomy patients. Interventions are described to restore the flow of aqueous to the filtering bleb in the early postoperative period, to manage flat anterior chambers with both high and low intraocular pressures, to manage a failing filtering bleb, and to manage hypotony. Herein we discuss current methods for controlling IOP in the postoperative period.

Glaucoma↗
PubMed1997

The effect of heparin-coated intraocular lenses on intraocular pressure following combined trabeculectomy and cataract surgery.

PURPOSE: To review the effects on intraocular pressure control of the use of standard and heparin-coated intraocular lenses (IOLs) following combined cataract and glaucoma surgery after a minimum period of 2 years. METHODS: Case note review of all patients with glaucoma who required cataract extraction combined with trabeculectomy and who were randomized to either of the two IOL types. The number of ocular hypotensive medications and the intraocular pressures were recorded pre-operatively and at 3, 6, 18 and 24 months following surgery. RESULTS: The two groups (9 receiving standard IOLs and 10 heparin-coated IOLs) were comparable for age, sex and follow-up, as were the pre-operative intraocular pressures and number of treatments. Post-operatively, all patients achieved an intraocular pressure < 21 mmHg at the final visit, with only one patient in each group requiring topical medication, but the standard lens group had a higher intraocular pressure at 2 years (p<0.05). The magnitude of the fall from the pre-operative values was greater in the heparin-coated lens group at 2 years after surgery (p<0.02). The presence of a visible drainage bleb occurred equally frequently in the two groups. CONCLUSIONS: Use of a heparin-coated IOL does not adversely affect the intraocular pressure control following combined cataract and drainage surgery. The greater fall in intraocular pressure at 2 years in those receiving a heparin-coated IOL may have occurred by chance.

Aged↗
PubMed1997

Hyaluronan polymer size modulates intraocular pressure.

To investigate whether the occasional increase in intraocular pressure that may arise following injection of sodium hyaluronan into the anterior segment during intraocular surgery is related to the polymer size of hyaluronan, controlled fragmentation of hyaluronan chains in vitro was obtained using progressive incubation with testicular hyaluronidase. The profile of molecular sizes of the hyaluronan polymers in various preparations was determined using molecular sieve column chromatography. Individual preparations were injected into six rabbit eyes and intraocular pressures were measured every one-half hour for 12 hours. Longer incubations of hyaluronan with hyaluronidase resulted in more extensive degradation with accumulation of shorter chain lengths. In the rabbit, mean intraocular pressure for 12 hours following intracameral injection of hyaluronic acid (HA) is proportional to the polymer size of HA. The occasional elevation of intraocular pressure that occurs following injection of hyaluronan during ophthalmic surgery can be avoided in part by assuring the rapid fragmentation of the large molecular size hyaluronan polymer.

Animals↗
PubMed1998

The effect of deep posterior subtenon injection of corticosteroids on intraocular pressure.

PURPOSE: To investigate the effect of posterior subtenon injections of corticosteroids on intraocular pressure in a variety of ocular diseases. METHODS: We retrospectively analyzed 202 consecutive posterior subtenon corticosteroid injections (148 of methylprednisolone acetate, 80 mg, and 54 of triamcinolone acetonide, 40 mg) in 63 eyes of 55 patients (26 male, 29 female; mean age +/- SD, 60.17 +/- 26.55 years). All patients had received topical or systemic corticosteroids before the injection, and no rise in intraocular pressure had been noted. Preinjection and postinjection intraocular pressure measurements were compared by two-tailed paired t test. Statistical analysis was performed separately by patient (first injection of first injected eye), by eye (first injection of each eye), and by all injections. To detect increase in intraocular pressure during follow-up, statistical analysis was performed separately 14 to 90 days, 91 to 150 days, and 151 to 270 days after injection. RESULTS: No statistically significant difference was found between preinjection and postinjection intraocular pressure measurements. A power calculation in the most stringent subanalysis (by patient) proved that there is only a 3.87% chance to statistically miss a clinically significant rise in intraocular pressure from 15 to 21 mm Hg. CONCLUSIONS: Posterior subtenon injection of corticosteroids does not cause an increase in intraocular pressure. All patients in our study had been treated previously with topical or systemic corticosteroids and did not react with an excessive increase in intraocular pressure. This safety of repository corticosteroids may therefore not apply to patients whose status in responding to corticosteroids is not known.

Adolescent↗
PubMedDate not supplied

Intraocular pressure in leprosy patients without clinically apparent anterior segment pathology.

A widely prevalent notion is that intraocular pressures are generally lower in leprosy patients than in normal individuals. Applanation intraocular pressures were recorded in one hundred sixty-six leprosy patients who had no clinically visible anterior segment pathology and in one hundred and eleven healthy controls. Mean (SD) intraocular pressures in leprosy patients (13.6 (3.0) mm Hg) did not differ significantly from that of controls (13.1 (2.7) mm Hg). Eyes of only 1.5% of the leprosy patients had pressures of 7 mm Hg or less. Correlation coefficients (r) between age, sex and intraocular pressures were not statistically significant both in leprosy patients and in controls. No statistically significant differences in mean intraocular pressures were noted when leprosy patients were grouped according to the Ridley and Jopling classification. Duration of disease also did not affect the intraocular pressures. Neither did smear positivity or differing bacterial indices. This study questions the widely held belief that low intraocular pressures are a common feature in leprosy and contends that in the era of MDT where ocular complications associated with low intraocular pressures are thought to be less, the occurrence of low intraocular pressure may not be as common a phenomenon as it is believed to be.

Adolescent↗
PubMed2002

Assessment of intraocular pressure in children by digital tension.

BACKGROUND: Measurement of intraocular pressure by digital tension is a procedure that warrants study to determine if it could reliably yield pressure measurements for young children. METHODS: Sixty-two children (mean age, 3.8 years) served as subjects for the study. The examiner determined each child's digital tension in mmHg, classifying the measurement as soft to touch, medium to touch, or hard to touch. A masked examiner measured the intraocular pressure with a non-contact tonometer. RESULTS: Ninety-eight percent of the digital tension measurements yielded correct classification of the pressure when compared with non-contact tonometry results. The correlation for the digital tension determination of intraocular pressure with non-contact tonometry measurements was significant: 0.38 (p < 0.05) for O.D. and 0.39 (p < 0.05) for O.S. CONCLUSIONS: This study suggests use of digital tension as a reliable means of obtaining the intraocular pressure of young children. Digital tension tends to under-estimate the intraocular pressure when compared to non-contact tonometry readings.

Child, Preschool↗
PubMed1986

Intraocular pressure--physiology and implications for anaesthetic management.

The major factors controlling intraocular pressure during surgery are the dynamic balance between aqueous humour production in the ciliary body and its elimination via the canal of Schlemm; the auto-regulation and chemical control of choridal blood volume; the extraocular muscle tone and vitreous humour volume. Prior to surgical incision of the anterior chamber in open intraocular procedures, a low-normal intraocular pressure is mandatory to avoid the hazards of iris or lens prolapse and vitreous loss associated with sudden decompression. In general, the central nervous system depressant drugs, hypnotics, narcotics, major tranquillizers, volatile anaesthetic agents are associated with a reduction in intraocular pressure, with the exception of ketamine and possibly trichloroethylene. The mechanism of action of anaesthetic agents in reducing intraocular pressure may involve a direct effect on central diencephalic control centres, reduction of aqueous production, facilitation of aqueous drainage or relaxation of extraocular muscle tone. Succinylcholine administration is associated with a significant rise in intraocular pressure, with a peak increase between two to four minutes following administration and a return to base line values after six minutes. The intraocular hypertensive effect may be due to a tonic contraction of the extraocular muscles, choroidal vascular dilatation or relaxation of orbital smooth muscle. Despite many claims to the contrary, no reported method to date has been shown to consistently prevent the intraocular hypertensive response to intravenous succinylcholine administration. Because the non-depolarizing relaxants are associated with a reduced intraocular pressure, a barbiturate-non-depolarizing relaxant technique utilizing preoxygenation and cricoid pressure has evolved as the most commonly employed induction technique for the emergency repair of a penetrating eye injury. The alternative non-depolarizing relaxant pretreatment-barbiturate-succinylcholine technique may offer the advantages of more rapid onset of relaxation with only minor increases in intraocular pressure and in a carefully controlled rapid sequence induction technique may be the most acceptable method of handling emergency penetrating eye injuries.

Anesthesia↗
PubMed1997

The mechanism of intraocular pressure rise during cyclocryotherapy.

PURPOSE: Intraocular pressure (IOP) spikes that occur during cyclocryotherapy for advanced glaucoma may further injure the already damaged glaucomatous optic nerve and be responsible for visual impairment that may occur after this treatment. The authors investigated the mechanism of pressure rise to see whether it can be avoided and thus prevent further optic nerve injury. The authors postulated that intraocular ice forms during the cryo procedure and causes the pressure changes. METHODS: Intraocular pressure was monitored using a pneumatonometer during 15 cryocycles of four patients with advanced glaucoma and 21 cryocycles of five normal rabbits. A simple thermal model was developed to analyze the relation between volume expansion and pressure rise in the eye. The physical effect of freezing rabbit eye structures was investigated in vitro. RESULTS: The largest pressure spikes observed during the cryocycles in this work were increases of 32 mm Hg for humans and 25 mm Hg for rabbits. The mean value of the IOP immediately before and after the cryo freezing stage was 53 +/- 1 and 68 +/- 2 mm Hg, respectively, for humans and 22 +/- 1 and 32 +/- 1 mm Hg for rabbits. The parameters of the thermal model were determined from the observed IOP spikes. Calculated thaw times were consistent with measured times for return to precryo IOPs. In vitro cryoapplication (rabbit eye) showed the formation of an ice ball internal to the eye. CONCLUSIONS: Volumetric increase of the intraocular content related to the formation of an ice ball in the eye, is the mechanism of pressure spikes during cyclocryotherapy. Because this complication is unavoidable, other cyclodestuctive methods may be more prudent, particularly in patients with advanced glaucoma.

Animals↗
PubMed1984

Pseudophakia and intraocular pressure.

We studied the change in intraocular pressure in 373 consecutive eyes undergoing cataract extraction with intraocular lens implantation between Jan. 1, 1981, and May 31, 1982. There was a mean increase in intraocular pressure of 0.1 mm Hg following this surgery. This increase, however, was not statistically significant (P greater than .5). There was a mean rise in pressure of 0.8 mm Hg in the eyes undergoing intracapsular surgery and a mean fall in pressure of 0.6 mm Hg in the eyes undergoing extracapsular surgery (P less than .05). The change in pressure was unrelated to age, surgeon, or lens type. The results of a separate analysis of 16 eyes with a preoperative diagnosis of glaucoma and eight eyes with ocular hypertension were similar.

Cataract Extraction↗
PubMed1996

Interaction between head-down tilt and anterior chamber infusions on intraocular pressure of anesthetized rats.

Head-down tilt or infusions of a balanced salt solution into the anterior chamber of the eye raise intraocular pressure. We measured intraocular pressure directly in adult male Sprague-Dawley rats, anesthetized with pentobarbital, and subjected to 45 degrees head-down tilt alone, tilt with an anterior chamber infusion (0.087 microliter min-1), or tilt with an infusion containing arginine vasopressin. The intraocular pressure of the three groups differed during the 1 hr tilt and recovery periods. In the case of tilt alone, intraocular pressure quickly reached a peak after tilting, partially decreased during the tilt period, recovered to baseline immediately after tilt, then a secondary rise occurred. Combined infusion and tilt caused a slower rise to peak intraocular pressure, and only a partial recovery occurred during the 1 hr recovery period. Combined vasopressin infusion and tilt caused a gradual rise in intraocular pressure of a lesser magnitude than the other groups, followed by a rapid recovery to baseline pressure and no secondary rise. Systemic arterial pressure was stable within and between the groups. The underlying mechanism for these differing response patterns is unknown. However, some evidence indicates that infusions are independent of aqueous synthesis rate, and that vasopressin, acting on a V1 receptor subtype reached from the anterior chamber, exerts a vascular effect.

Analysis of Variance↗
PubMed1996

Increased intraocular pressure after macular hole surgery.

PURPOSE: To determine the incidence and timing of increased intraocular pressure in eyes with an idiopathic macular hole treated with bovine transforming growth factor-beta 2 (TGF-beta 2) with different intraocular gas concentrations, recombinant TGF-beta 2, or placebo. METHODS: Intraocular pressure was measured preoperatively and two days, two weeks, six weeks, and three months postoperatively in two prospective studies of the treatment of idiopathic macular hole with vitrectomy. Group 1 consisted of 95 eyes treated with bovine TGF-beta 2. Eyes in this group were treated with different concentrations of air and perfluoropropane (C3F8) intraocular gas bubbles. Fifteen eyes were treated with air, 15 eyes with 5% perfluoropropane, 15 eyes with 10% perfluoropropane, and 50 eyes with 16% perfluoropropane. Group 2 consisted of 29 eyes treated with recombinant TGF-beta 2. Twenty-six eyes were treated with placebo in a double-masked, randomized, placebo-controlled study evaluating recombinant TGF-beta 2 with a 16% perfluoropropane intraocular gas bubble. RESULTS: At the two-week examination, the intraocular pressure in Group 1 eyes was > 30 mm Hg in four (26.7%) of 15 eyes treated with air, two (13.3%) of 15 eyes treated with 5% perfluoropropane, one (8.3%) of 12 eyes treated with 10% perfluoropropane, and nine (19.1%) of 47 eyes treated with 16% perfluoropropane. There was no statistically significant difference in the risk of increased intraocular pressure in eyes treated with short-, intermediate-, or long-duration gas tamponade using bovine TGF-beta 2. The intraocular pressure in Group 2 was > 30 mm Hg at the two-week examination in 11 (39.3%) of 28 eyes receiving recombinant TGF-beta 2 compared with one (4.3%) of 23 eyes receiving a placebo (P = .006). CONCLUSIONS: Some eyes develop increased intraocular pressure after vitreous surgery for macular hole, and the increase occurs most frequently between two days and two weeks postoperatively. The risk of increased intraocular pressure is somewhat increased in eyes treated with bovine TGF-beta 2 but is markedly increased in eyes in which recombinant TGF-beta 2 is used as an adjunctive agent for macular hole surgery. Intraocular injection of growth factors produced by similar recombinant DNA techniques may result in potentially dangerous increased intraocular pressure several weeks after surgery. Impurities in the recombinant TGF-beta 2 may explain the relatively high risk of increased intraocular pressure.

Chemotherapy, Adjuvant↗
PubMed2001

The relationship of cataract maturity to intraocular pressure in dogs.

OBJECTIVE: To determine the distribution of intraocular pressure, as measured by applanation tonometry, in dogs with cataracts, and compare these tonometric results to the different stages of cataract formation (incipient, immature, mature, and hypermature). Animals studied Retrospection study of canine clinical patients (86 dogs). PROCEDURES: All records of dogs presented from 1991 to 1996 to the university veterinary medical teaching hospital for diagnosis of cataracts and evaluation for cataract surgery were reviewed. The tonometric measurements from the initial ophthalmic examination were selected in cataractous and nonglaucomatous eyes either receiving no topical or no systemic medications. The stage of cataracts was based on the degree of opacification, tapetal reflection, clinical vision, and visibility of the ocular fundus by indirect ophthalmoscopy. The distribution of tonometric results were grouped by the cataract maturity, and compared by anova and Tukey's general linear tests. RESULTS: Intraocular pressure with incipient cataracts ranged from 9 to 17 mmHg (mean 12.7 +/- 1.2 mmHg). Intraocular pressure with immature cataracts ranged from 3 to 27 mmHg (mean 13.6 +/- 0.6 mmHg). For the mature cataracts, IOP ranged from 5 to 22 mmHg (mean 11.9 +/- 0.7 mmHg). For the hypermature cataract group, IOP ranged from 4 to 23 mmHg (mean 10.8 +/- 0.6 mmHg). Comparison of the tonometric results among the different stages of cataract formation indicated a significant difference (P = 0.0086) between only the immature and hypermature groups. CONCLUSIONS: Intraocular pressure in lens-induced uveitis (LIU) is lowered but the relationship to the stage of cataract maturity is less clear. Significant tonometric differences were present between the immature and hypermature cataract groups, but these differences are too small to be clinically useful. Decreased intraocular pressure of dogs with all stages of cataract formation suggests concurrent LIU during all stages of cataract formation, especially with the mature and hypermature stages. The average tonometric measurements in dogs with these cataracts were about two standard deviations below the mean IOP reported in normal dogs.

Animals↗
PubMed1984

The intraocular pressure and the pupillary responses of conscious rabbits to racemic erythro-alpha-methylnorepinephrine.

The intraocular pressure and the pupillary responses in conscious rabbits to racemic erythro-alpha-methylnorepinephrine (alpha MeNE) have been investigated and its activity compared to L-norepinephrine (NE). Aqueous solutions of alpha MeNE applied topically caused dose-dependent decreases of intraocular pressure and of pupil dilatation. The maximal intraocular pressure response to alpha MeNE exceeded that to NE, and the sensitivity of the intraocular pressure response exceeded that to NE by 10-20 times. The onset of the decrease in intraocular pressure to alpha MeNE was rapid and contrasted to the slow onset of the intraocular hypotensive response to NE. Preganglionic cervical sympathotomy did not effect the intraocular pressure and the pupillary responses to either alpha MeNE or NE. Superior cervical ganglionectomy induced supersensitivity to NE but not to alpha MeNE. Studies using alpha 1, alpha 2, and beta adrenoceptor antagonists indicated that the intraocular pressure responses to alpha MeNE were mediated primarily by alpha 2 and beta adrenoceptors whereas the responses to NE were mediated primarily by alpha 1 adrenoceptors. The observations are discussed in the light of recent data of the affinities of alpha MeNE and NE to alpha 1, alpha 2, and beta adrenoceptors. The high potency of alpha MeNE compared to NE in decreasing intraocular pressure and in dilating the pupil does not correlate with their binding affinities to alpha and beta adrenoceptors. The observations support an alternative explanation that the differences in the potencies of alpha MeNE and NE are due to differences in rates of inactivation of the two compounds in the adrenergic neurone.

Adrenergic alpha-Antagonists↗
PubMed1995

The temporal relationship between intraocular pressure and extraocular muscle activation in cats.

The temporal relationship between intraocular pressure and extraocular muscle activation was studied in cats in response to the administration of the depolarizing muscle relaxant, succinylcholine (i.e. bolus doses of 0.1 and 1.0 mg/kg). Simultaneous changes in intraocular pressure, extraocular muscle force, extraocular electromyograms (EMGs), limb muscle EMGs and hindlimb muscle afferent activity were recorded. Increases in intraocular pressure were associated with extraocular muscle activation and had two components: (1) an initial abrupt increase (lasting seconds) which correlated with fasciculations within the extraocular and hindlimb muscles; and (2) a latter more sustained component (minutes) presumably due to tonic muscle activation which correlated with increases in hindlimb muscle afferent activity (e.g. due to sustained activation of bag 1 intrafusal fibers by succinylcholine). In a separate group of animals, in which the extraocular muscles were detached from the right eye bilateral intraocular pressures were measured: depolarization by succinylcholine caused a significant increase in intraocular pressure only for the eye with intact muscles. Thus, increases in intraocular pressure following the administration of succinylcholine are directly related to the changes in extraocular muscle tension which is dependent on both tonic and phasic muscle fiber responses.

Animals↗
PubMed1988

Intraocular pressure following extracapsular cataract extraction and posterior chamber intraocular lens implantation.

Knowledge of the incidence of both short- and long-term elevation of intraocular pressure (IOP) after extracapsular cataract extraction (ECCE) and posterior chamber intraocular lens (PC-IOL) insertion is essential for the practicing ophthalmologist. We reviewed retrospectively the IOP data in 384 consecutive patients (506 eyes) that underwent the above procedure. A postoperative rise of 8 mm Hg above baseline or above 23 mm Hg was observed in 149 eyes (29%). Secondary glaucoma well controlled medically developed in 21 eyes (4%). Three eyes developed glaucoma after the first year postoperatively. Therefore, over the total follow-up period of 6 years, 24 eyes (4.7%) developed pseudophakic glaucoma. None, however, required laser or other surgical intervention. These results further support the prevailing view that ECCE with PC-IOL is the procedure of choice.

Adult↗
PubMed2000

The Advanced Glaucoma Intervention Study (AGIS): 7. The relationship between control of intraocular pressure and visual field deterioration.The AGIS Investigators.

PURPOSE: To investigate the association between control of intraocular pressure after surgical intervention for glaucoma and visual field deterioration. METHODS: In the Advanced Glaucoma Intervention Study, eyes were randomly assigned to one of two sequences of glaucoma surgery, one beginning with argon laser trabeculoplasty and the other trabeculectomy. In the present article we examine the relationship between intraocular pressure and progression of visual field damage over 6 or more years of follow-up. In the first analysis, designated Predictive Analysis, we categorize 738 eyes into three groups based on intraocular pressure determinations over the first three 6-month follow-up visits. In the second analysis, designated Associative Analysis, we categorize 586 eyes into four groups based on the percent of 6-month visits over the first 6 follow-up years in which eyes presented with intraocular pressure less than 18 mm Hg. The outcome measure in both analyses is change from baseline in follow-up visual field defect score (range, 0 to 20 units). RESULTS: In the Predictive Analysis, eyes with early average intraocular pressure greater than 17.5 mm Hg had an estimated worsening during subsequent follow-up that was 1 unit of visual field defect score greater than eyes with average intraocular pressure less than 14 mm Hg (P =.002). This amount of worsening was greater at 7 years (1.89 units; P <.001) than at 2 years (0.64 units; P =.071). In the Associative Analysis, eyes with 100% of visits with intraocular pressure less than 18 mm Hg over 6 years had mean changes from baseline in visual field defect score close to zero during follow-up, whereas eyes with less than 50% of visits with intraocular pressure less than 18 mm Hg had an estimated worsening over follow-up of 0.63 units of visual field defect score (P =.083). This amount of worsening was greater at 7 years (1.93 units; P <.001) than at 2 years (0.25 units; P =.572). CONCLUSIONS: In both analyses low intraocular pressure is associated with reduced progression of visual field defect, supporting evidence from earlier studies of a protective role for low intraocular pressure in visual field deterioration.

Adult↗