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Results for “INTRAOCULAR PRESSURE”

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PubMed1982

Effect of histamine-2 receptor blockade by cimetidine on intraocular pressure in humans.

The effect of an intravenous infusion of cimetidine (2 mg/kg of body weight/hr) on intraocular pressure and gastric acid secretion was determined in four healthy young adults and compared with the effect of a control infusion of normal saline. Cimetidine, a powerful histamine-2 receptor antagonist, abolished basal acid secretion, indicating that it was pharmacologically active, yet had no effect on intraocular pressure. Therefore, cimetidine may be given safely to patients with normal intraocular pressure. An additional observation was that intraocular pressure in all experiments declined linearly with repeated applanation tonometry for almost two hours before reaching a stable level.

Adult↗

PubMed1991

Effects of caffeinated coffee on intraocular pressure.

This study examined the effects of caffeinated coffee on the intraocular pressure of nonglaucomatous subjects. Subjects were randomly assigned to receive each of three treatments: caffeinated coffee, hot water, and no fluid. All subjects were given the three treatment conditions over 3 days. The study revealed that intraocular pressure after ingesting caffeinated coffee was significantly higher than after receiving the other two treatment conditions. It was further found that increased intraocular pressure was maintained at significant levels over a 3-hour period. No significant changes were found in the pulse rate, and findings on blood pressure were inconclusive.

Adult↗

PubMed1991

Effects of the R(+)- and S(-)-isomers of beta-adrenoceptor blockers with intrinsic sympathomimetic activity, befunolol and carteolol, on rabbit intraocular pressure.

Effects of the R(+)- and S(-)-isomers of befunolol and carteolol, beta-adrenoceptors with intrinsic sympathomimetic activity, on the rabbit intraocular pressure were tested. The intraocular pressure was decreased by instillation of the R(+)- and S(-)-isomers of befunolol (0.1 and 0.3%) and of carteolol (1.0%) to the eye and attained the minimum level at 60 min. However, 0.3% of the R(+)- and S(-)-isomers of carteolol did not influence the pressure. The corresponding time courses for the intraocular pressure for the R(+)- and S(-)-isomers did not differ, suggesting that in the treatment of glaucoma, the therapeutic advantage of the R(+)-isomers of befunolol and carteolol may be similar to the S(-)-isomers.

Adrenergic beta-Antagonists↗

PubMed2001

[New epidemiologic approach to intraocular pressure in an Antananarivo population].

PURPOSE: The Malagasy population is a mixture from many ethnic origins. The Merina population is generally of Asiatic origin. The purpose of this study was to report the main characteristics of Merina intraocular pressure and their risk factors. METHODS: Screening was conducted in 1507 apparently healthy subjects with no known ocular disease (such as glaucoma) living in Antananarivo. Intraocular pressure was measured with a Goldmann tonometer. RESULTS: Males predominated (54.81%). The distribution of aplanation pressure followed an asymmetrical Gaussian pattern. In the Merina population, mean intraocular pressure was low (13.50+/-3.5mmHg, m+/-SD) and increased with age. There was no difference by gender. The prevalence of ocular hypertension was 1.43%. It was slightly higher in females and increased to the age of 50 years, then decreased. Among possible risk factors, only familial glaucoma was significantly frequent. CONCLUSION: The mean intraocular pressure in the Merina population is lower than the accepted statistical mean and is similar in both sexes. The prevalence of intraocular hypertension is also low but glaucoma develops early. Some of our data are similar to those observed in western populations (mean intraocular pressure increases with age). Other points are similar to the Asian population (low mean intraocular pressure and low frequency of intraocular hypertension and its progression after 50 years).

Adult↗

PubMed1997

Intraocular pressure in inbred mouse strains.

PURPOSE: To develop a protocol to measure the intraocular pressure (IOP) of living mice and to determine the IOP of genetically different mouse strains. METHODS: Eyes of anesthetized animals were cannulated with a very fine fluid-filled glass microneedle. The microneedle was connected to a pressure transducer, and the pressure signal was analyzed with a computer system. Intraocular pressures of male C3H/He iota, C57BL/ 6 iota, A/iota, and BALB/c iota mice were determined. RESULTS: Differences in IOP were detected between genetically distinct mouse strains maintained in virtually identical environments. C3H/He iota was the strain with the highest average IOP (13.7 +/- 0.8 mm Hg). This strain average was 1.4 mm Hg higher than that for C57BL/6 iota (12.3 +/- 0.5 mm Hg; P = 0.14), 4.3 mm Hg higher than that for A/iota (9.4 +/- 0.5 mm Hg; P < 0.001), and 6 mm Hg higher than that for BALB/c iota (7.7 +/- 0.5 mm Hg; P < 0.001). CONCLUSIONS: The authors have developed an accurate and reliable procedure for measuring intraocular pressure in living mice. This procedure can detect IOP differences between groups of mice that differ by genotype.

Animals↗

PubMed2006

[How to ensure that glaucoma is stable? Intraocular pressure].

In patients with open-angle glaucoma, intraocular pressure (IOP) obtained through treatment should guard against the progression of glaucoma damage. This depends on the initial state of intraocular pressure, but also on the stage of glaucoma, how fast the alterations are progressing, the patient's age and life expectancy, as well as the presence of other risk factors. To determine the ideal level of treated IOP, the term "target pressure" is often used. This term is very much open to criticism, however, because it calls on a static figure for what is highly variable biological information belonging to the body's biological rhythms. A large number of formulas are used to calculate this target pressure number, but all of them come up against the disadvantage of not taking into account the variations in IOP during the day/night cycle. Yet it is these very variations that can characterize the severity of the disease in terms of IOP. In a glaucoma patient, the IOP curve plotted over 24 h has higher IOP values during the day than at night, contrary to a healthy subject. Fluctuations of more than 10 mmHg are not rare during the day/night cycle, most often with many peaks, which are deleterious for retinal nerve fibers. These dynamic pressure parameters are essential both in determining the therapeutic strategy and in evaluating the effectiveness of treatment. In practice, with any case of open-angle glaucoma and before any treatment is given, a diurnal curve should be established. Six to eight measurements between 8 AM and 6 or 8 PM should be enough. They should be carefully combined with concomitant measures of systemic blood pressure. Once treatment has started, we suggest that a new diurnal curve be established 1 month and then 4 months after the beginning of treatment. The treatment will be modified if needed, based on IOP criteria established at 1 month, and on IOP, perimetric, and anatomic criteria determined again at 4 months. If the disease continues to worsen despite a satisfactory diurnal IOP, IOP should be measured over 24 h, associated with Holter monitoring, looking for an escape of pressure at night.

Circadian Rhythm↗

PubMed1990

The effect of intraocular gas and fluid volumes on intraocular pressure.

Large increases in the intraocular pressure (IOP) of postoperative gas-containing eyes may require the removal of gas or fluid to reduce the IOP to the normal range. Application of the ideal gas law to Friedenwald's equation provides a mathematical model of the relationship between IOP, intraocular gas and fluid volumes, and the coefficient of scleral rigidity. This mathematic model shows that removal of a given volume of gas or fluid produces an identical decrease in IOP and that the more gas an eye contains, the greater the volume reduction necessary to reduce the pressure. Application of the model shows that the effective coefficient of scleral rigidity is low (mean K, 0.0021) in eyes with elevated IOP that have undergone vitrectomy and retinal cryopexy and very low (mean K, 0.0013) in eyes with elevated IOP that have undergone placement of a scleral buckle and band. By using the appropriate mean coefficient of rigidity, the volume of material to be aspirated to produce a given decrease in IOP can be predicted with clinically useful accuracy.

Atmospheric Pressure↗

PubMedDate not supplied

Placement of a collagen glaucoma drainage device to control intraocular pressure and chronic iritis secondary to juvenile rheumatoid arthritis.

A patient with juvenile rheumatoid arthritis and chronic iritis is reported with intraocular pressure near 30 mm Hg and previous episodes of intraocular pressure as high as 50 mm Hg despite maximally tolerated medical therapy. Because of the potential risk involved with a full-thickness filtration procedure, it was decided that a nonpenetrating deep sclerectomy would be appropriate, followed by placement of a collagen glaucoma drainage device to maintain aqueous outflow. Immediately postoperatively, intraocular pressure was stabilized. At 24 months postoperatively, intraocular pressure was well controlled at 15 mm Hg with patient receiving only Lotemax. No significant complications were noted at any point in the postoperative course. Because of the patient's predisposition for serious complications frequently associated with trabeculectomy, nonpenetrating deep sclerectomy with the collagen glaucoma drainage device was an effective alternative for this patient.

Adult↗

PubMed1996

An assessment of intraocular pressure during fractionated peribulbar anaesthesia.

This study of 20 patients undergoing elective cataract surgery was performed to investigate the change in intraocular pressure that accompanies extraconal peribulbar anaesthesia. We have demonstrated that each injection during peribulbar anaesthesia causes a small rise in intraocular pressure. The routine use of conventional external ocular compression overcomes this pressure rise and safely provides a satisfactory and progressive reduction in intraocular pressure prior to surgery. Our findings suggest that the volumes of anaesthetic solutions used in fractional peribulbar anaesthesia, if used in conjunction with external compression devices, result in intraocular pressures acceptable for intraocular surgery.

Aged↗

PubMed1997

Effects of topical alpha-substituted anandamides on intraocular pressure in normotensive rabbits.

PURPOSE: Anandamides have been observed to lower intraocular pressure in the rabbit eye, preceded by a period of hypertension. Amidases are thought to catabolize these compounds into their component parts, including arachidonic acid. Direct application of arachidonic acid has been observed to cause a marked rise of intraocular pressure. Thus, anandamide analogs resistant to catabolism were thought possibly devoid of this initial hypertension, and their effects on rabbit IOP investigated. METHODS: A series of chiral alpha-substituted anandamides were synthesized and studied for their effect on the intraocular pressure (IOP) of normotensive pigmented rabbits. Each test compound was dissolved in an aqueous 2-hydroxypropyl-beta-cyclodextrin solution (containing 3% polyvinyl alcohol) and administered (62.5 micrograms) unilaterally to the eye. RESULTS: The most promising compounds caused a statistically significant reduction of IOP (vs. vehicle) in the treated eyes. Of these, the R-alpha-isopropyl compound exhibited the best activity tested. Unlike the alpha-unsubstituted analogs previously studied, hypotensive effects were not preceded by an initial elevation of IOP and indomethacin pre-treatment (12.5 mg, s.c.) did not eliminate the IOP response, as demonstrated by administered R-alpha-isopropyl anandamide. CONCLUSIONS: Catabolism of alpha-unsubstituted anandamides may account for their observed intraocular hypertensive effects. The physiological mechanism by which alpha-substituted anandamides work apparently differs from that of the more easily metabolized alpha-unsubstituted compounds.

Animals↗

PubMed1976

A light microscopic, autoradiographic study of axoplasmic transport in the optic nerve head during ocular hypotony, increased intraocular pressure, and papilledema.

Cyclocryotherapy of the monkey eye reliably produces transient increased intraocular pressure followed by prolonged hypotony, during which papilledema occurs. Axoplasmic transport was studied while the intraocular pressure was both increased and decreased after cyclocryotherapy by autoradiography following the intravitreal injection of tritiated leucine and proline. Surgical fistulization of the anterior chamber was also used to produce hypotony and papilledema. Significant alterations of both the rapid and the slow components of axoplasmic transport were demonstrated in the nerve head during increased intraocular pressure, and in ocular hypotony with papilledema.

Animals↗

PubMed1995

[Increased intraocular pressure after cataract extraction--effect of surgical technique, surgical procedure and preventive drug administration. A prospective, randomized double-blind study].

BACKGROUND: We performed a double-masked, randomized and prospective study to compare the effect of surgical technique, surgeon's experience, and prophylactic medication on the intraocular pressure rise after cataract extraction. PATIENTS AND METHODS: Intraocular pressure of 120 patients was measured the day before, as well as two to four, five to seven and 22 to 24 hours after uncomplicated cataract extraction. 47 patients were operated with phacoemulsification and sclerocorneal sutureless tunnel (phaco/tunnel). 61 patients with phacoemulsification and corneoscleral incision and suture (phaco/suture), and 12 patients with extracapsular technique (ECCE). 48 operations were done by inexperienced surgeons (less than 200 intraocular operations), 72 by experienced surgeons (300-2000 intraocular operations). Patients were treated with either levobunolol, acetazolamide, apraclonidine, or placebo. Each treatment group contained 30 patients. RESULTS: In all groups, the mean intraocular pressure increased to a maximum at five to seven hours after surgery. The pressure rise was significantly higher in the ECCE group (20.6 mm Hg) than in the phaco/suture group (10.5 mm Hg) and in the phaco/tunnel group (5.4 mm Hg, p always < 0.05). Eyes operated by inexperienced surgeons had a significantly (p < 0.005) greater pressure rise (12.9 mm Hg) than eyes operated by experienced surgeons (7.1 mm Hg). Treatment had no significant (p = 0.41) effect on the intraocular pressure rise. CONCLUSION: The intraocular pressure rise after cataract extraction strongly depends on the surgical technique and to a lesser extent, on the surgeon's experience. At least for phacoemulsification, the effect of the prophylactic medication used in this study is small and appears to be clinically irrelevant.

Acetazolamide↗

PubMed2000

[Nocturnal measurements of intraocular pressure in patients with normal-tension glaucoma and sleep apnea syndrome].

BACKGROUND: About half of all normal-tension glaucoma patients and about one third of all primary open-angle glaucoma patients have sleep apnea syndrome. If sleep apnea syndrome causes some cases of glaucoma, the optic nerve damage could result from repetitive nocturnal hypoxias or from repetitive intraocular pressure elevations at the end of the apneas. In this study, we determined the intraocular pressure at the end of long apneas. PATIENTS AND METHODS: In three patients having sleep apnea syndrome and normal-tension glaucoma we recorded in a sleep laboratory during at least six hours of sleep the respiration (oxymetry, nasal and oral air flow, and inductive plethysmography). The intraocular pressure was measured with a pneumatonometer at predetermined times and compared to the values measured at the end of prolonged apneas. RESULTS: The intraocular pressure during normal respiration was in the first patient 19.5 +/- 1.0 mm Hg OD and 19.3 +/- 1.7 mm Hg OS, in the second patient 25.0 +/- 4.2 respectively 25.5 +/- 4.9 mm Hg and in the third one 22 +/- 1.0 respectively 21.3 +/- 1.3 mm Hg. At the end of prolonged apneas the intraocular pressure was in the first patient 19.0 +/- 0.0 mm Hg OD and 19.5 +/- 0.7 mm Hg OS, in the second patient 26.5 +/- 0.6 and 26.8 +/- 0.1 mm Hg and in the third one 20.0 +/- 0.0 respectively 21.0 +/- 0.0 mm Hg. The difference between intraocular pressures during normal respiration and at the end of prolonged apneas was not significant (p > 0.1 for each comparison, paired t-test). CONCLUSIONS: We did not find an increase of intraocular pressure at the end of prolonged apneas compared to periods of normal respiration in patients with sleep apnea syndrome and normal-tension glaucoma. If sleep apnea syndrome causes some cases of glaucoma, it seems more probable that the the optic nerve is damaged by the repetitive hypoxias. Alternatively, an unknown factor might induce both, sleep apnea syndrome and normal-tension glaucoma.

Aged↗

PubMed1980

Bilateral recording of human intraocular pressure with an improved applanating suction cup tonograph.

An improved applanating suction cup for continuous recording of human intraocular pressure is described. The new cup adheres better, is easier to calibrate, and is simpler to handle, mainly due to a different curvature of the applanating surface. The interspace between the applanating and the applanated surface, in which the pressure is measured, is continuously flushed with saline from a flow system (Intraflo) connected to the dome of the pressure transducer. The suction that attaches the cup to the cornea is - as in the previous model - provided by a saline filled tube hanging from the cup. In 51 human cadaver eyes the calibration for static pressures and pressures oscillating up to 124 cycles per min was: intraocular pressure = 0.9 X cup pressure -3 (mmHg), r = 0.995. The cup reduced ocular rigidity by 5% only and increased the intraocular pressure transiently by 4 mmHg when applied. Simultaneous bilateral recordings were obtained in 400 normo- or hypertensive eyes from 206 subjects. The cup was atraumatic, and the method can be strongly recommended when accurate, bilateral pressure recordings are desired for periods up to one h in supine subjects. At intraocular pressures above 35 mmHg, the tonograph may underestimate the pressure under certain, unfavourable conditions.

Tonometry, Ocular↗

PubMed1981

Intraocular pressure and cardiovascular risk variables.

The relationship between intraocular pressure and several cardiovascular risk factors was evaluated in data from the Health and Nutrition Examination Survey of 1971 to 1974. Mean IOP increased with increasing age for all groups. Blacks tended to have slightly higher levels than did whites. Intraocular pressure was correlated positively with systemic blood pressure in all groups. The pattern of the association of IOP with hematocrit reading, sedimentation rate, pulse rate, and serum cholesterol level was not consistent in the four race-sex groups. In all groups the variables in a regression model accounted for, at most, 8% of the variability in IOP reading.

Adolescent↗

PubMedDate not supplied

Changes in intraocular pressure after laser in situ keratomileusis.

PURPOSE: To evaluate changes in intraocular pressure (IOP) measurements by Goldmann applanation tonometry after laser in situ keratomileusis (LASIK) for myopia and myopic astigmatism, and to assess the accuracy of Goldmann applanation tonometry measurements after LASIK in these eyes. METHODS: LASIK was performed on 166 eyes of 93 patients for correction of myopia and myopic astigmatism. Intraocular pressure was measured by Goldmann applanation tonometry at the central and temporal parts of the cornea before and at 1, 3, 6, and 12 months after LASIK. The amount of change in IOP was computed and its relation to different variables was evaluated by regression analysis. RESULTS: Intraocular pressure measured at the center of the cornea was reduced by a mean of 3.69 +/- 1.63 mmHg after LASIK. Multiple regression analysis showed that the decrease in IOP was related to the preoperative IOP and the change in central corneal thickness after LASIK. Measurements of IOP at the temporal part of the cornea were also reduced by a mean of 2.39 +/- 1.71 mmHg. There was wide variability in the amount of difference between the temporal and central measurements after LASIK (temporal measurements were higher than central by 0 to +4 mmHg). CONCLUSION: LASIK for myopia produced underestimation of IOP measured by Goldmann applanation tonometry at the central part of the cornea by a mean of 3.69 +/- 1.63 mmHg. The decrease of IOP was related to preoperative IOP and the change in central corneal thickness after LASIK. Temporal Goldmann applanation tonometry measurements, although decreased after LASIK, were less reliable.

Adult↗

PubMed1984

Intraocular pressure the day of argon laser trabeculoplasty in primary open-angle glaucoma.

Argon laser trabeculoplasty was performed in one eye of 57 phakic patients with primary open-angle glaucoma. The eyes received a mean of 78 +/- 7 treatments over 360 degrees to the anterior trabecular meshwork. The power was titrated to produce blanching without bubble formation. Increased intraocular pressure (range +1 to +22 mmHg) occurred in 30 of the 57 (53%) eyes 1 hour after treatment. Eight (14%) of these eyes had a clinically significant elevation defined by all of three criteria: (1) an intraocular pressure greater than 30 mmHg, (2) greater than a 30% increase over the mean prelaser intraocular pressure, and (3) greater than a 10 mmHg increase over the peak prelaser diurnal intraocular pressure curve. These eight patients received either oral glycerine or acetazolamide. A rebound increase in intraocular pressure requiring repeat medical treatment occurred in four of the eight eyes. Two additional eyes without a pressure elevation 1 hour after treatment showed a later elevation. This was first detected 4 hours postoperatively in one eye and 7 hours after treatment in another eye. The 1-hour postoperative measurement detected most patients with clinically significant increased intraocular pressure (8 of 10 eyes) but these required continued observation for rebound increases. Patients with advanced glaucomatous visual field loss should also be followed closely to detect late increases in intraocular pressure (2 of 10 eyes).

Adult↗

PubMed2004

Intraocular pressure variations after diode laser photocoagulation for threshold retinopathy of prematurity.

PURPOSE: To investigate the intraocular pressure (IOP) variations occurring after indirect diode laser photocoagulation for threshold retinopathy of prematurity. DESIGN: Prospective, nonrandomized, comparative study. PARTICIPANTS: A study group-21 consecutive premature babies (42 eyes) undergoing diode laser photocoagulation for retinopathy of prematurity-and control groups-32 premature babies (64 eyes) undergoing retinal examination with or without scleral indentation. INTERVENTION: Intraocular pressure was measured with a portable electronic tonometer before, immediately after, and 1, 2, and 3 days after diode laser photocoagulation in the study group; before retinal examination in control group 1; and before and after retinal examination with scleral indentation in control group 2. MAIN OUTCOME MEASURE: Intraocular pressure after diode laser photocoagulation for threshold retinopathy of prematurity. RESULTS: Mean IOP in the study group rose from 15 mmHg (standard deviation [SD] = 4.1) before coagulation to 33.2 mmHg (SD = 7.8; range, 20-50) immediately after, and then dropped to 22.2 (SD = 5.2), 16.5 (SD = 3), and 14.5 mmHg (SD = 2.1) 1, 2, and 3 days later, respectively. All the changes were statistically significant at P<0.0001, except for the difference between days 2 and 3 (P = 0.096). Mean baseline IOPs were 16.3 mmHg (SD = 3.7) in control group 1 and 15.7 mmHg (SD = 2.3) in control group 2 (P = 0.84 between control group 1 and study group, and P = 0.32 between control group 2 and the study group). At termination of the retinal examination with scleral indentation (control group 2), IOP measured 15.1 mmHg (SD = 2.2) (P = 0.49 compared with baseline). CONCLUSIONS: Intraocular pressure may be significantly elevated after diode laser photocoagulation for retinopathy of prematurity. The mechanism and long-term clinical implications of this observation should be investigated.

Female↗