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PubMed2005

[Usability of self-tonometry under ambulatory conditions to obtain daily profiles of intraocular pressure at home].

BACKGROUND: Diurnal profiles of intraocular pressure at opening times in the doctor's office do not deliver enough information, especially nightly and early morning measurements are lacking. Self-tonometry using the automatic self-tonometer "Ocuton S" might be suitable to achieve valid 24-hour IOP profiles without the need to stay in a hospital. MATERIALS AND METHODS: 96 people were taught to use the automatic self-tonometer once. Those who had learnt self-tonometry after this training underwent a diurnal IOP profile for 24 hours in the hospital using Goldmann tonometry and self-tonometry every 4 hours at the same times of day. One to three days later, they created a third IOP profile at home using self-tonometry at the same intervals as at the hospital. The IOP profiles were then tested for equality. RESULTS: 50 people out of 96 were able to perform self-tonometry after one training session. The IOP measurements of all three IOP profiles did not differ by more than 2 mmHg and thus may be considered comparable. There was no significant difference between daily curves, either. CONCLUSIONS: Self-tonometry using the automatic self-tonometer "Ocuton S" appears to be suitable to record diurnal profiles of intraocular pressure at home.

Adult↗
PubMed1989

Trabecular precipitates and elevated intraocular pressure following argon laser trabeculoplasty.

Two patients with pseudoexfoliation glaucoma underwent argon laser trabeculoplasty for control of intraocular pressure. Within 1 month both patients developed elevated intraocular pressure associated with many large inflammatory precipitates on the trabecular meshwork detected only by gonioscopy. Treatment with topical steroids for 7 to 10 days resolved these precipitates and lowered the intraocular pressure. We believe our patients had severe trabeculitis occurring as a late reaction to argon laser trabeculoplasty. An increase in intraocular pressure following trabeculoplasty warrants careful gonioscopic examination; in fact we recommend routine gonioscopy for all patients after laser treatment.

Aged↗
PubMed2005

The influence of peripheral iridotomy on the intraocular pressure course in patients with pigmentary glaucoma.

PURPOSE: To evaluate the influence of laser peripheral iridotomy on the long-term intraocular pressure course for patients with pigmentary glaucoma. PATIENTS AND METHODS: Retrospective analysis of data contributed by members of the American Glaucoma Society on patients with bilateral pigmentary glaucoma, who received uniocular laser iridotomy. The main outcome measure was the post-laser intraocular pressure course of the treated eyes, compared with the fellow, untreated eyes. RESULTS: Sixty patients were included in the study, 46 of whom were observed for a minimum of 2 years (mean 70.3 +/- 26.0 months; range 24-113 months). Among the 14 patients who were observed for less than 2 years, the mean intraocular pressure in the treated eyes increased 0.36 +/- 2.63 mm Hg, compared with the fellow, untreated eyes. Among the 46 patients, observed for 2 years or more, the mean intraocular pressure in the treated eyes decreased 4.0 +/- 5.4 mm Hg, compared with 1.9 +/- 3.8 mm Hg in the fellow eyes (P = 0.005). However, analysis by linear models indicates that a higher mean baseline intraocular pressure in the treated eyes accounts for the apparent treatment effect of laser peripheral iridotomy. CONCLUSION: The study does not provide support for the benefit of laser peripheral iridotomy in the long-term intraocular pressure control of patients with pigmentary glaucoma, when the data are subjected to rigid statistical analysis. This does not disprove the benefit of laser iridotomy in this patient population, but underscores the need for a large, prospective study to address the question.

Adult↗
PubMed1987

Intraocular pressure, systemic blood pressure, and age: a correlational study.

An attempt was made to study the associations between age, intraocular pressure, and systolic blood pressure. The eyes of 90 non-glaucomatous, ocular normotensive patients and of 142 ocular hypertensive patients were examined. A third group was formed from these two by stratification, to mirror the intraocular pressure distribution in the general population. In all three groups systolic blood pressure was positively correlated with age. In the stratified group a 'chain' model was consistent with the data. Intraocular pressure was significantly negatively correlated with systolic blood pressure; any apparent association between intraocular pressure and age was fully accounted for through the correlation between systolic blood pressure and age.

Aged↗
PubMed1977

Mechanism of methacholine-induced rise in intraocular pressure in the dog.

The mechanism of the methacholine-induced rise in intraocular pressure in the dog was studied to determine the basis of the relationship, if any, between lens thickness and intraocular pressure. The results rule out a vasodilator component in methacholine intraocular pressure elevation, and the tonometric recording of the elevation makes unlikely the involvement of methacholine stimulation of the rectus muscles of the eye. Thus, indirect evidence points to methacholine stimulation of ciliary muscle contraction with consequent thickening of the lens as responsible for its intraocular pressure-elevating effect and, hence, the ability of the response under investigation to specify the cycloplegic liability of a neurotropic antispasmodic agent.

Animals↗
PubMed1999

Intraocular pressure measurement in the conscious rat.

PURPOSE: To develop a method for measurement of intraocular pressure in conscious, unsedated rats. METHODS. The animal was gently held with a thick fabric mitten, topical anesthetic drops were instilled and the Tono-Pen was applied to the cornea. RESULT: Measurements in a total of 51 animals did not differ significantly among four strains studied: the overall mean intraocular pressure+/-standard deviation was 13.0+/-1.2 mm Hg. Several intraocular pressure tolerance limits were calculated from this conscious rat data to provide a baseline estimate for future studies. CONCLUSIONS: This measurement method in conscious rats may contribute to making this widely used laboratory animal available for intraocular pressure research.

Animals↗
PubMed2003

Effect of exercise on intraocular pressure and pulsatile ocular blood flow in a young normal population.

PURPOSE: The hypotensive effect of exercise on intraocular pressure is well documented, however, little is known about the effect of exercise on pulsatile ocular blood flow. This study examines this effect and follows the recovery of intraocular pressure and pulsatile ocular blood flow after a standard exercise period. METHODS: Eighteen visually normal subjects participated in a 4-min period of bicycle ergometry. Intraocular pressure and pulsatile ocular blood flow were measured by pneumotonometry before, immediately after exercise, and at regular intervals during the recovery period. RESULTS: Intraocular pressure was found to decrease significantly with strenuous exercise and recovered gradually toward baseline over a period of 30 min. Pulsatile ocular blood flow increased significantly immediately after exercise then returned to baseline levels between 5 and 10 min after stopping exercise. CONCLUSIONS: This study confirms the hypotensive effect of exercise on intraocular pressure and shows that exercise significantly increases pulsatile ocular blood flow.

Adult↗
PubMedDate not supplied

Changes in intraocular pressure after laser in situ keratomileusis for myopia, hyperopia, and astigmatism.

PURPOSE: Reports have shown that photorefractive keratectomy changes intraocular pressure (IOP) in myopic eyes by changing the thickness and curvature of the cornea. Changes in intraocular pressure after laser in situ keratomileusis (LASIK) for hyperopia led the authors to evaluate IOP after LASIK for various refractive errors. METHODS: The measurement of intraocular pressure with a Goldman applanometer in the central cornea was evaluated before and 3 months after LASIK in 100 eyes of 55 patients with various refractive errors. Corneal thickness (pachymetry) and corneal topography were evaluated. RESULTS: After LASIK, a significant decrease of intraocular pressure was observed in most eyes: mean 11.9 +/- 3.2 mmHg before and 9.8 +/- 2.6 mmHg at 3 months after surgery (P < .001). Mean decrease in IOP was 2.75 +/- 3.3 mmHg (P < .0001) for myopic eyes, 2.28 +/- 2.43 mmHg (P < .001) for hyperopic eyes, and 1.47 +/- 2.5 mmHg (P < .0012) for astigmatic eyes. IOP reduction was not significantly correlated to the amount of ablation (r = 0.05) or to corneal thickness. CONCLUSION: Intraocular pressure decreased in myopic, hyperopic, and astigmatic eyes after LASIK. The reduction was not correlated to the amount of tissue removed or to flattening or steepening of the central cornea.

Adolescent↗
PubMed1976

The biphasic intraocular pressure response of rabbits to epinephrine.

A study has been made of the pupillary and intraocular pressure responses of conscious rabbits to daily topical applications of submaximal doses of epinephrine. On the first day, epinephrine caused rapid pupil dilation which preceded a prolonged -ecrease of intraocular pressure. On the second and subsequent days, the application of the same dose of epinephrine increased the duration of the pupillary response and caused a biphasic pressure response in all treated eyes; an initial increase of intraocular pressure lasting two to four hours followed by decrease of intraocular pressure below the initial value which lasted for more than twenty-four hours. The beta-receptor antagonist, propranolol, and the alpha-receptor antagonist, phenoxybenzamine, caused small and large reductions, respectively, in the hypertensive response to epinephrine. Phenoxybenzamine, but not propranolol, also inhibited the pupil dilation and the hypotensive response to epinephrine. Topical administration of phenoxybenzamine strongly inhibited the hypertensive response to epinephrine but left unaffected the pupillary response.

Administration, Topical↗
PubMed1981

Diurnal variations in intraocular pressure. Chronic open angle glaucoma: preliminary report.

Human beings have a diurnal variation in their intraocular pressure and this variation is related to the sleep-wake cycle. Patients with chronic open angle glaucoma have a similar fluctuation in intraocular pressure and, even without medication, may achieve a "normal" intraocular pressure several hours into their sleep period. Two patients with chronic open angle glaucoma, maintained on their usual miotic therapy, also maintained a normal diurnal fluctuation in intraocular pressure as did one patient with a unilaterally transected optic nerve and another with a surgically divided trigeminal nerve.

Adult↗
PubMed2001

Effect of cataract surgery on intraocular pressure in eyes with previous trabeculectomy.

PURPOSE: To determine the course of the intraocular pressure in eyes in which cataract surgery was performed after trabeculectomy. METHODS: This was a retrospective study of consecutive patients who were scheduled for routine cataract surgery. The patients had previously undergone glaucoma filtering surgery. Pre- and postoperative data were evaluated. Both the status of glaucoma and the increase in visual acuity were monitored. RESULTS: Patients operated on over a six-year period were enrolled. The mean interval between glaucoma surgery and cataract surgery was 58.1 months. The mean duration of follow-up after cataract surgery was 31.4 months, with a minimum of 12 months. The mean central visual acuity increased by 4 lines. Before cataract surgery, 53% of the eyes had complete success (group 1), while 28% had qualified success (group 2) and the remaining 19% were failures (group 3). From group 1, 61% remained a complete success until the last visit. No eye of group 1 developed a failure. In group 2, 23% were a complete success at the final follow-up, while 4% failed. In group 3, only 35% were failures while the remaining 65% were a complete or qualified success. CONCLUSIONS: Eyes with a well-controlled intraocular pressure following trabeculectomy seem to have a favorable prognosis after subsequent cataract surgery. Eyes with qualified success or failure before cataract surgery have a slight chance of improvement in intraocular pressure control. Cataract surgery had no markedly negative effect on the intraocular pressure overall. Performing trabeculectomy and cataract surgery at different times may still be a feasible option as opposed to combined procedures.

Adult↗
PubMed1998

The effectiveness of intraocular pressure reduction in the treatment of normal-tension glaucoma. Collaborative Normal-Tension Glaucoma Study Group.

PURPOSE: In a companion paper, we determined that intraocular pressure is part of the pathogenesis of normal-tension glaucoma by analyzing the effect of a 30% intraocular pressure reduction on the subsequent course of the disease. We report an intent-to-treat analysis of the study data to determine the effectiveness of pressure reduction. METHODS: One eligible eye of 145 subjects with normal-tension glaucoma was randomized either to no treatment (control) or to a 30% intraocular pressure reduction from baseline. To be eligible for randomization, the normal-tension glaucoma eyes had to show documented progression of field defects or a new disk hemorrhage or had to have field defects that threatened fixation when first presented for the study. Survival analysis compared time to progression of all randomly assigned patients during the course of follow-up from the initial baseline at randomization. In a separate analysis, data of patients developing cataracts were censored at the time that cataract produced 2 lines of Snellen visual acuity loss. RESULTS: Visual field progression occurred at indistinguishable rates in the pressure-lowered (22/66) and the untreated control (31/79) arms of the study (P = .21). In an analysis with data censored when cataract affected visual acuity, visual field progression was significantly more common in the untreated group (21/79) compared with the treated group (8/66). An overall survival analysis showed a survival of 80% in the treated arm and of 60% in the control arm at 3 years, and 80% in the treated arm and 40% in the controls at 5 years. The Kaplan-Meier curves were significantly different (P = .0018). The analyses gave different results because of a higher incidence of cataract in the group that underwent filtration surgery. CONCLUSIONS: The favorable effect of intraocular pressure reduction on progression of visual change in normal-tension glaucoma was only found when the impact of cataracts on visual field progression, produced largely by surgery, was removed. Lowering intraocular pressure without producing cataracts is beneficial. Because not all untreated patients progressed, the natural history of normal-tension glaucoma must be considered before embarking on intraocular pressure reduction with therapy apt to exacerbate cataract formation unless normal-tension glaucoma threatens serious visual loss.

Aged↗
PubMed1989

Intraocular pressure after cardiopulmonary bypass surgery.

The ocular effects of cardiopulmonary bypass surgery were prospectively studied in 46 patients. We examined preoperative and post-operative visual acuity, intraocular pressure, body weight, fluids infused during surgery, hematocrit, and cardiopulmonary bypass time. On the first postoperative day mean intraocular pressure increased 2.1 mm Hg (P = .003) from baseline preoperative levels. Over the first postoperative day intraocular pressure increased in 29 (63%) of the patients. Three patients (7%) had a greater than 10 mm Hg rise. The mean intraocular pressure returned to baseline by the third postoperative day. Patient weight increased from preoperative levels an average of 9.3 lbs (P less than .0001) on day 1 and 6.5 lbs on day 3. Mean hematocrit decreased 11.3% (P less than .0001) on day 1 from baseline and remained at that level through day 3. None of the patients complained of visual dysfunction during the course of this study and none showed more than a two-line decrease in near visual acuity. The increase in intraocular pressure did not correlate with the postoperative weight gain or hemodilution. However, the medications necessary after cardiac surgery may be a significant confounding variable. This study demonstrates that one cause of ocular problems from cardiopulmonary bypass surgery may be related to the dynamics of intraocular pressure.

Adult↗
PubMed1990

Aspects of oxygen and glucose consumption in the retina: effects of high intraocular pressure and light.

Studies on retinal oxygen and glucose consumption in cats and pigs are reviewed and recent experiments with the deoxyglucose method in monkeys are described. In all three species, the retina is supplied with nutrients by both the retinal and the choroidal blood vessels. Studies on regional blood flow and differences in arteriovenous concentration in cats have indicated that under conditions of general anesthesia and exposure to laboratory light, the oxygen supply from the choroid is about 5.6 microliters/min and that from the retinal vessels, 1.3 microliters/min. In pigs the corresponding figures were about 4 and 2.9 microliters/min, respectively. Moderate reductions in perfusion pressure caused by increments in intraocular pressure or reductions in arterial blood pressure resulted in little change in oxygen tension in the inner retina, due to efficient autoregulation of retinal blood flow. Reduced choroidal blood flow was to a large extent compensated by increased differences in arteriovenous concentration. Studies using the deoxyglucose method in monkeys indicated that pentobarbital anesthesia and constant illumination tend to reduce the metabolism of the retina. In darkness, glucose consumption in the photoreceptors was higher than that recorded under conditions of constant illumination with white light. Flickering light at 4 Hz enhanced glucose consumption in the inner retina. At very high intraocular pressures glucose consumption in the retina was enhanced, probably as a result of partial ischemia, with a shift to more anaerobic glucose metabolism.

Animals↗
PubMed2001

Evaluation of travoprost as adjunctive therapy in patients with uncontrolled intraocular pressure while using timolol 0.5%.

PURPOSE: To evaluate the intraocular pressure-lowering efficacy and safety of travoprost 0.0015% and 0.004%, dosed daily in the evening compared with vehicle, in patients with open-angle glaucoma or ocular hypertension, whose intraocular pressure was not adequately controlled on timolol 0.5% twice daily (twice daily). METHODS: Subjects who qualified at screening began a run-in period dosing timolol twice daily for 3 weeks. If the subjects had an intraocular pressure of 24 to 36 mm Hg at 8 AM and 21 to 36 mm Hg at 10 AM and 4 pm in at least one eye on timolol, they were randomized to one of two concentrations of travoprost (0.0015% or 0.004%) or vehicle solution every day and were followed for 6 months. Four hundred twenty-six subjects were randomized. The mean intraocular pressure at 8 AM, 10 AM, and 4 PM in the patient's eye with the higher intraocular pressure was used for the analysis. RESULTS: Mean baseline values (25 mm Hg) for subjects at eligibility (while maintained on timolol) were not significantly different (P <.0001) among the treatment groups. The intraocular pressure was lowered an additional -5.7 to -7.2 mm Hg and -5.1 to -6.7 mm Hg in the travoprost 0.004% and 0.0015% concentrations, respectively. These changes were significantly (P < or =.0001) different from the vehicle group (-1.3 to -2.8 mm Hg). The intraocular pressure range on treatment at all visit times over the 6-month treatment period ranged from 17.9 to 19.2 mm Hg for travoprost 0.004% and 18.3 to 20.1 mm Hg for travoprost 0.0015% compared with 22.4 to 24.1 mm Hg for vehicle. Average hyperemia scores ranged from trace to mild (mean 0.5 on a scale of 0 = none/trace; 1= mild; 2 = moderate; 3 = severe) for all treatment groups. No iris pigmentation changes were observed in any patient during this study. There were no clinically or statistically significant changes from baseline in visual acuity, ocular cells and flare, fundus parameter, cup-to-disk ratio and visual field between the treatment groups. There were no serious adverse events reported for any treatment group. CONCLUSIONS: Travoprost produced clinically relevant and statistically significant additional intraocular pressure reductions from baseline when used adjunctively with timolol in subjects with open-angle glaucoma or ocular hypertension.

Adrenergic beta-Antagonists↗
PubMed1999

Effects of elevated intraocular pressure on haemoglobin oxygenation in the rabbit optic nerve head: a microendoscopical study.

Intraocular pressure dependent reactions of optic nerve head vasculature and intracapillary haemoglobin oxygenation (HbO(2); oxygen saturation) were studied in the center and at the rim of the rabbit optic nerve head (ONH) as well as in the choroid, by a new combination of microendoscopy and simultaneous haemoglobin spectrophotometry. In 13 anesthetized albino rabbits the vasculature and the intracapillary Hb-oxygenation were studied by a microendoscope which was introduced into the eye bulb. Photometric measurements were performed via a beam splitter with the Erlangen micro-lightguide spectrophotometer (EMPHO) from the center of the endoscopic picture. The haemoglobin oxygenation was calculated by real time analysis of the spectral curves. Intraocular pressure was elevated stepwise from 20-80 mmHg. At the rim of the optic nerve head the vascular diameters as well as the intracapillary HbO(2)-values were stable till an intraocular pressure of 60 mmHg and decrease after IOP elevation to 70 and 80 mmHg. In contrast, in the center of the optic nerve head and in the choroid these parameters decline already from 40-50 mmHg on. At an IOP of 60 mmHg (P<0.01) and 70 mmHg (P<0.05) HbO(2)is significantly lower in the ONH center than at the rim. In the center and the choroid HbO(2)is well maintained between 20 and 40 mmHg. After pressure release at the end of the experiment HbO(2)increased to 94.3+/-4.6% (rim) and 98.8+/-1.5% (center) of the initial value at 20 mmHg (difference not significant).By the high spatial resolution of this new optical method we were able to demonstrate that the center of the optic nerve head is more sensitive to changes in intraocular pressure than the optic nerve head rim. Thus, tissue damage after critical haemodynamic and oxygenation parameters seems more probable in the relatively poor perfused center of the ONH than in the overperfused rim.

Animals↗
PubMed2002

[Prevalence of glaucoma and normal intraocular pressure among adults aged 50 years or above in Shunyi county of Beijing].

OBJECTIVE: To estimate the prevalence of glaucoma and normal intraocular pressure among older adults aged 50 years or above in Shunyi county of Beijing. METHODS: Cluster sampling was used in randomly selecting 5 555 individuals aged 50 years or above in Shunyi county in fall, 1996. The examines received the visual acuity and general eye examination, and in the mean time attention was paid to rule out glaucoma, including inquiry of family and personal history of glaucoma, measurement of anterior chamber depth and intraocular pressure, examination of the optic disc. RESULTS: The examinations about glaucoma were finished in 4 880 individuals. The response rate was 87.85%. In this population, the prevalence of glaucoma was 2.07%. The prevalence of the primary angle closure glaucoma, primary open angle glaucoma and secondary glaucoma was 1.66%, 0.29% and 0.12% respectively. The prevalence of the variety of glaucoma was increasing by aging. The visual function in 64.00% of glaucoma patients was damaged in certain degree. The rate of the bilateral blindness among glaucoma patients was 16.00%. These patients were all 60 years old or above. The rates of unilateral blindness, bilateral allow vision and unilateral low vision were 17.00%, 23.00% and 8.00%, respectively. The mean and standard deviation of the intraocular pressure among the normal eyes were (13.53 +/- 2.20)mm Hg(1 mm Hg = 0.133 kPa). The tendency of the mean normal intraocular pressure is decreasing by aging. CONCLUSIONS: Glaucoma is a serious eye disease leading to blindness according to the prevalence and the visual function of the glaucoma patients. The mean intraocular pressure among the normal eyes is lower than the expected value. The lower value (18 mm Hg) of the upper limited normal intraocular pressure should be used in screening glaucoma patients among the older adults.

Age Factors↗