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Results for “INTRAOCULAR PRESSURE”

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At least 433 records · Page 24Linked to original sources

PubMed2004

[Changes in intraocular pressure during pregnancy].

PURPOSE: The purpose of this study was to define physiological changes in intraocular pressure during pregnancy. MATERIAL AND METHODS: 182 healthy pregnant women were examined cross-sectionally throughout the pregnancy. After measuring systolic and diastolic blood pressure full ophthalmological examination was performed (visual acuity, refractive error, intraocular pressure, slit lamp examination and fundus exam). All subjects were free from any systemic or ocular diseases. RESULTS: Intraocular pressure significantly decreased during successive stages of pregnancy. The results are presented as means SD. In the control group mean IOP was 15.6 +/- 1.81 mmHg. During first ten weeks of pregnancy mean IOP was 15.33 +/- 1.98 mmHg, between 11-20 hbd was 14.52 +/- 2.37 mmHg, between 21-30 hbd was 13.47 +/- 2.19 mmHg, and towards the end of pregnancy (31-40 hbd) was 12.5 +/- 1.96 mmHg. The mean fall of IOP during whole pregnancy was 3.1 +/- 0.38 mmHg (p < 0.001). In these subjects pregnancy decreased IOP by 19.8%. CONCLUSIONS: The study results showed a gradual, statistically significant fall of intraocular pressure during pregnancy.

Adult↗

PubMed1988

Physiological variables affecting intraocular pressure in a population study.

Intraocular pressure (IOP) and several other parameters were measured on 560 subjects as part of a vision and health screening program. The sample included a large proportion of American Indians with diabetes (15.2%) and obesity. Multiple regression analysis showed that the percentage of ideal body weight index and average blood pressure both had independent effects on IOP, whereas age, blood sugar, sex, degree of Indian blood, and diabetes did not, although the latter three variables narrowly missed having a statistically significant effect in at least one eye. The analysis of variance showed that diabetes was associated with elevated IOP. This association was independent of random blood sugar, blood pressure, obesity index, and age.

Adolescent↗

PubMed1992

Effect of carbachol on intraocular pressure in small-incision cataract surgery.

Sixty patients, who underwent phacoemulsification and implantation of a folded polyHema intraocular lens were assigned to two groups. Following wound closure 0.5 ml of 0.01% carbachol or balanced salt solution was instilled into the anterior chamber. Healon was used in all eyes but evacuated from the capsular bag behind the intraocular lens and the anterior chamber. Intraocular pressure was measured the day before as well as 6 and 18 hours postoperatively. At 6 hours the mean change of intraocular pressure from baseline was -2.8 +/- 5.3 mmHg in the carbachol group compared with +4.7 +/- 8.0 mmHg in the BSS group (p < 0.0001). At 18 hours the mean change from baseline was -3.0 +/- 4.6 mmHg in the treatment group and +2.3 +/- 8.5 in the control group (p < 0.0001). Intraocular pressure exceeding 25 mmHg at 6 hours was observed in 8 (27%) eyes of the control group but none of the treatment group. At 18 hours 4 (13%) eyes of the control group and 1 (3%) of the carbachol group still had an increase of intraocular pressure. Summarizing our results we conclude that the effect of Healon on the postoperative intraocular pressure is successfully counteracted by its aspiration from the capsular bag and the anterior chamber, especially when carbachol is used for intraoperative miosis.

Aged↗

PubMed1997

Measurements of intraocular pressure throughout the pregnancy in Pakistani women.

BACKGROUND: Decrease in intraocular pressure (IOP) during pregnancy has been reported by previous studies, but amount of decrease varies from study to study. Moreover, previous studies have concentrated on the last trimester of pregnancy or one reading per trimester. IOP changes throughout the pregnancy have never been described. Therefore, the present study was planned to determine IOP throughout the pregnancy, after placing control on IOP affecting factors. SUBJECTS AND METHODS: Thirty-six pregnant and same numbers of non-pregnant women of the same age group were studied. IOP measurements were taken at four week intervals throughout the pregnancy, with the Goldmann applanation tonometer. RESULTS: As compared to control subjects, up to 8th week, IOP remained the same. At 12th week, it becomes significantly lower. The IOP differences between first and second (P < 0.05), and second and third (P < 0.001) trimesters of pregnancy were significant. In every subject, IOP decreased during pregnancy. However, there were variations among individuals in the extent of IOP decrease. CONCLUSIONS: With advancing pregnancy, intraocular pressure decreases. Knowledge of the normal level of intraocular pressure in various stages of pregnancy may help glaucoma screeners.

Female↗

PubMed1983

A major pathway for the regulation of intraocular pressure.

There has been a suspicion on the part of many clinicians and research scientists that intraocular pressure can be regulated by neural and/or humoral influences upon the rate of aqueous humor formation. It has been difficult, if not impossible, to separate specific influences of the central nervous system upon intraocular pressure from vascular induced or other secondary alterations. The past two decades have witnesses a great deal of study of the role of the adrenergic nervous system upon the regulation of intraocular pressure. From the investigations it is possible to formulate an integrated concept that can place years of work and speculation on a firm molecular foundation. The secretory tissue of the eye, the ciliary processes, contain an enzyme receptor complex, comprised by receptor complex, comprised by receptor bound membrane proteins, the catalytic moiety of the enzyme, a guanyl nucleotide regulatory protein (or N protein) and other features. The enzyme can be activated by well known neurohumoral or humoral agents that consist of catecholamines, glycoprotein hormones produced by the hypothalamic pituitary axis, and other related compounds, including placental gonadotropin. These compounds cause the ciliary epithelia to produce cyclic AMP at an accelerated rate. Cyclic AMP, as a second messenger, causes, either directly or indirectly, a decrease in the rate of aqueous humor formation that may be modulated by cofactors. Clinical syndromes fit the experimental data so that an integrated explanation can be given for the reduced intraocular pressure witnessed under certain central nervous system and adrenergic influences. The molecular biology of this concept provides important leads for future investigations that bear directly both upon the regulation of intraocular pressure and upon glaucoma.

Adenylyl Cyclases↗

PubMed1998

Nilvadipine inhibits acute rise of aqueous flare and intraocular pressure induced by prostaglandin E2 in pigmented rabbits.

To evaluate the possible role of calcium channel blocker on changes in aqueous flare and intraocular pressure induced by prostaglandin E2 (PGE2) in pigmented rabbits, we examined the effects of nilvadipine and nicardipine (calcium channel blockers). PGE2, 25 micrograms/ml, was administered using a glass cylinder. Nilvadipine or nicardipine was injected intravenously. Aqueous flare was measured by a laser flare cell meter. Intraocular pressure was measured by a noncontact tonometer. After administration of PGE2, aqueous flare and intraocular pressure increased and then decreased. Increased flare and elevated intraocular pressure following PGE2 administration were inhibited by nilvadipine in a dose-dependent manner (5-500 micrograms/kg body weight). These responses were inhibited only slightly by nicardipine at the same concentration. Nilvadipine injected 30 min before PGE2 application inhibited the increase maximally. The inhibitory effect was found on days 1, 3, 5, and 7 by daily administration of nilvadipine. A good correlation between the inhibition of intraocular pressure and the inhibition of increased flare by nilvadipine was found. We believe that Ca2+, or calcium channel blocker-related substances may be involved in the mechanism of PGE2-induced elevation of aqueous flare and intraocular pressure in the pigmented rabbit.

Animals↗

PubMed1991

Nonarteritic anterior ischemic optic neuropathy and intraocular pressure.

Several reports have suggested that nonarteritic anterior ischemic optic neuropathy (AION) may be related to increased intraocular pressure. We reviewed the records of 45 patients aged 48 through 86 years with nonarteritic AION (10 patients had bilateral AION) for intraocular pressure measurements and the diagnosis of glaucoma or suspected glaucoma. This group was compared with 45 age- and sex-matched patients with normal eye examination results. The mean +/- SD intraocular pressures were 16.3 +/- 3.3 mm Hg for 45 eyes of the 45 patients with AION and 16.1 +/- 2.8 mm Hg for 45 eyes of the 45 control patients (paired t test, P = .70). Among patients with unilateral AION, intraocular pressure was not greater in the involved eye than in the uninvolved eye. Three patients with AION had a previous diagnosis of glaucoma, while three of the control patients were being followed up with suspected glaucoma. We found no evidence in our series to support the hypothesis that AION is associated with increased intraocular pressure.

Aged↗

PubMed1976

The prognostic value of HLA-B12 and HLA-B7 antigens in patients with increased intraocular pressure.

The presence of the histocompatibility antigens HLA-B12 or HLA-B7 in 76 patients with increased intraocular pressure and a GG response to topical corticosteroids (intraocular pressure over 31 mm Hg after six weeks of topical 0.1% dexamethasone eyedrops, four times daily) correlated with the development of glaucomatous visual field loss. In close agreement with prevalences in patients with primary open-angle glaucoma, 14 (88%) of the 16 patients with increased intraocular pressure and a GG response who developed glaucomatous visual field loss had either HLA-B12 or B7 antigens. Fourteen (41%) of 34 patients with increased intraocular pressure and a GG response who had B12 or B7 antigens developed glaucomatous visual field loss but only two (5%) of 42 similar patients without either antigen had visual field loss. Other factors such as the initial intraocular pressure, the horizontal cup/disk ratio, and family history of glaucoma proved less valuable as prognostic indicators in this series.

Adrenal Cortex Hormones↗

PubMed1990

Relationship between asymmetry of visual field defects and intraocular pressure difference in an untreated normal (low) tension glaucoma population.

The importance of intraocular pressure on the pathogenesis of optic disc damage in normal (low) tension glaucoma has been much debated. This paper looks at the interocular difference in intraocular pressure in an untreated group of 60 patients with normal (low) tension glaucoma. In addition it assesses whether any relationship exists in any one subject between the higher intraocular pressure and the more severe visual field defect. We found that this relationship occurred in 22% (13) of the subjects. In the other 78% (47) of this population no correlation could be found. The existence of such a sizeable subgroup suggests that patients with normal tension glaucoma may be divided into those where intraocular pressure level could be important in the pathogenesis of the visual field defect and a majority where this relationship is less likely.

Adult↗

PubMed1996

The effect of physical fitness on intraocular pressure in Chinese medical students.

BACKGROUND: Virtually all the tissues and systems of the human body have been shown to be responsive to programs of exercise. Regarding the relationship between physical fitness and intraocular pressure (IOP), the existing literature is controversial with some associations inconsistent. In one study, IOP values were not dependent upon changes in physical fitness. In contrast to this, another study demonstrated that physical fitness significantly reduces intraocular pressure levels. In recent years it has been noted that intraocular pressure is a dynamic function and is subject to many influences both acutely and over the long term. The variety of results of previous studies may have come from several factors which can affect intraocular pressure. The present study was planned to investigate the effects of physical fitness on intraocular pressure in Chinese medical studies, after elimination of other affecting factors. METHODS: Forty medical students were categorized into control and experimental groups, each consisting of 20 subjects. The experimental group took a supervised exercise program for 10 weeks. Physical fitness was evaluated by measurement of maximum oxygen uptake with a Beckman O2 analyzer. Intraocular pressure was measured with the Goldmann applanation tonometer. RESULTS: After exercise training, the experimental group showed a marked increase in physical fitness. The difference of IOP between the control and experimental groups before exercise conditioning was 0.3 +/- 0.1 mmHg (P > 0.05). After 10 weeks, this difference increased to 1.1 +/- 0.4 mmHg (p < 0.05). CONCLUSIONS: This study concludes that physical fitness reduces intraocular pressure. Whether exercise conditioning has a role as a nonpharmacologic approach or as an addition to medical therapy must be left to future investigations.

Adult↗

PubMed1987

Intraocular pressure by noncontact tonometry with and without soft contact lenses.

We compared the intraocular pressure of 43 eyes (23 patients) with and without soft contact lenses. Two measurements were taken on each eye while the patients were wearing their soft contact lenses, and then immediately after the lenses were removed. Intraocular pressure measurements were taken by noncontact tonometry. The results showed that the power of the contact lens was a significant predictor of the change in intraocular pressure. In addition, when the 43 eyes were broken down into two groups, those with hyperopic lenses and those with myopic lenses, the difference in intraocular pressure was significantly larger for the group with hyperopic lenses than for the group with myopic lenses.

Contact Lenses, Hydrophilic↗

PubMed1988

Oculab Tono-Pen, Goldmann applanation tonometry, and pneumatic tonometry for intraocular pressure assessment in gas-filled eyes.

We performed 84 intraocular pressure measurements with the Oculab Tono-Pen, Goldmann applanation tonometer, and pneumatic tonometer in 47 eyes that had undergone pars plana vitrectomy and gas-fluid exchange. Measurements made by using the Tono-Pen were accurate when compared to those made by Goldmann tonometry (mean difference, 0.74 mm Hg). In a subset of eyes with increased intraocular pressure (greater than or equal to 25 mm Hg), the Tono-Pen provided measurements similar to those made by Goldmann applanation tonometry (P greater than .60), with only three of 39 readings (8%) underestimating the Goldmann pressure by more than 3 mm Hg. Pneumatic tonometry significantly underestimated the intraocular pressure in eyes with increased pressure (P less than .001), with 20 of 39 readings (51%) underestimating the Goldmann pressure by 5 mm Hg or more.

Evaluation Studies as Topic↗

PubMed2003

Relationship between postural change of the intraocular pressure and visual field loss in primary open-angle glaucoma.

PURPOSE: To determine the relationship between the postural changes of the intraocular pressure and the visual field loss in patients with primary open-angle glaucoma. METHODS: Eleven normal subjects and 11 patients with primary open-angle glaucoma were studied. Intraocular pressure was measured in both the sitting and the supine positions. Visual fields were measured with automated perimetry. RESULTS: When patients moved from a sitting to supine position, the intraocular pressure increased by an average of 3.1 +/- 0.4 mm Hg (mean +/- SEM) in normal subjects and 4.0 +/- 0.2 mm Hg in patients with primary open-angle glaucoma. There was a significant difference between the normal subjects and patients with primary open-angle glaucoma (P = 0.049). Intraocular pressure increased by 4.4 +/- 0.3 mm Hg (P = 0.02) in the worse eye for mean deviation and 3.6 +/- 0.3 mm Hg (P = 0.38) in the better eye for mean deviation. There was no significant difference in intraocular pressure in the sitting position between both groups. CONCLUSIONS: The greatest difference in intraocular pressure between the sitting and supine positions was observed in the worse eye of patients with primary open-angle glaucoma. This result suggests that damage to the optic nerve in primary open-angle glaucoma might occur when patients are asleep in the supine position.

Case-Control Studies↗

PubMed1991

Intraocular pressure 2 1/2 years after extracapsular cataract extraction and sulcus implantation of posterior chamber intraocular lens.

The intraocular pressure in 50 eyes of 50 patients was measured 2 1/2 years after planned extracapsular cataract extraction with intended implantation of a posterior chamber lens in the ciliary sulcus. The results were compared to the preoperative values, and the pressure observed after 4 months. Although a significant elevation was found from the fourth month (P = 0.015), the intraocular pressure at 2 1/2 years was found to be significantly lower than the preoperative value (P = 0.002). No significant difference was found in two subgroups in which transillumination defects in the iris or pigment in the lower anterior chamber angle was present.

Aged↗

PubMed1992

Normal intraocular pressure in man.

Whereas the values of 120/70 mm Hg are universally recognized as being normal for the parameter of systemic blood pressure, the value for 'normal intraocular pressure' remains very vague. Indeed, values between 7 and 21 mm Hg are often considered normal. However, a careful review of the literature and original data reported here suggest that the intraocular pressure in normal subjects, although dynamic, is a more accurate parameter than is generally expected. The normal value during the day in healthy, young adults is about 12 +/- 2 mm Hg, and it increases by 1 mm Hg per decade after 40 years of age.

Adult↗

PubMed2002

[The influence of silicone oil removal on intraocular pressure].

PURPOSE: The aim of this study was to evaluate the influence of silicone oil removal on intraocular pressure. MATERIAL AND METHOD: Our material consists of 98 patients (104 eyes), who underwent vitrectomy with silicone oil tamponade. Sixteen eyes in this group were aphakic before vitrectomy. The mean duration of silicone-oil tamponade was 8.8 months. We examined and compared intraocular pressure in all cases before vitrectomy, during tamponade and after silicone oil removal. RESULTS: The increased intraocular pressure (> 22 mmHg) was found in 27 eyes (seven of them were aphakic) during tamponade. We had to remove silicone oil due to glaucoma in 6 eyes (three of them were aphakic). In 9 eyes (four aphakic) the intraocular pressure was higher than 22 mmHg after silicone oil removal. Seven patients required additional topical medication and 2 patients were qualified for operation--trabeculectomy. Hypotony (< 10 mmHg) was observed in 11 eyes, and it coexisted with retinal redetachment in 4 cases. CONCLUSIONS: The increased intraocular pressure is a frequent complication of silicone oil tamponade, and it normalizes after silicone oil removal in most of these cases.

Adult↗

PubMed1985

Failure of acetazolamide to decrease intraocular pressure in patients with carbonic anhydrase II deficiency.

The effect of the carbonic anhydrase inhibitor acetazolamide on intraocular pressure was studied in two patients with carbonic anhydrase II deficiency and in six control subjects. The deficient patients had the autosomal recessive syndrome of osteopetrosis with renal tubular acidosis and cerebral calcification. A dose of 125 mg of intravenous acetazolamide caused a significant (P less than .01) decrease in intraocular pressure from baseline (15.0 +/- 1.5 mm Hg) in the control subjects one hour (11.3 +/- 1.5 mm Hg) and four hours (13.8 +/- 1.2 mm Hg) after drug administration. In contrast, the patients with carbonic anhydrase deficiency showed no such decrease in intraocular pressure; baseline intraocular pressure (19.2 +/- 0.2 mm Hg) was significantly unchanged (P greater than .5) at one hour (20.0 +/- 0.1 mm Hg) and four hours (19.2 +/- 0.2 mm Hg).

Acetazolamide↗

PubMed1995

Changes in intraocular pressure during low dose intravenous sedation with propofol before cataract surgery.

AIMS: This study examined the effects on intraocular pressure, pulse rate, and blood pressure of low dose intravenous sedation with propofol. METHODS: Twenty adult patients who were scheduled to undergo cataract surgery were given a single intravenous bolus (0.98 (SEM 0.4) mg/kg) of propofol for sedation before administering the local anaesthetic for cataract surgery. A small intravenous dose of lignocaine was the only other anaesthetic or sedative agent given. The intraocular pressure in the non-surgery eye, the pulse rate, and the blood pressure were measured before and after propofol induction. RESULTS: Compared with the preinduction baseline, there was a 17% to 27% (from 16.2 (0.7) mm Hg to 11.8 (0.7) mm Hg) decrease in intraocular pressure after propofol induction. A significant decrease in intraocular pressure occurred within the first minute and was still evident at 7 minutes when the measurements were stopped. There was also a 7%-12% increase in pulse rate during the first 4 minutes, a 12% decrease in mean systolic blood pressure, and a 7% decrease in mean diastolic blood pressure from baseline after propofol induction. CONCLUSION: A single low dose bolus of propofol used for sedation before cataract surgery caused a moderate reduction in intraocular pressure with minimal, easily managed side effects.

Aged↗