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Succinylcholine and intraocular pressure.

Thirty-one patients (61 eyes) had a rise in intraocular pressure averaging 8.2 mm Hg following the use of succinylcholine as a muscle relaxant prior to general anesthesia. Just prior to the start of surgery (an average of 14 minutes following Anectine administration), the tension had returned to the control level. Ten patients (20 eyes) had pancuronium used without succinylcholine. No change in intraocular tension was noted with this agent and pressure remained unchanged at the start of surgery. Work of other investigators, using the "spring back balance" test and strain gauge force measurement to rotate the globe, indicate that the effect of Anectine upon the extraocular muscles may take 20 to 30 minutes to wear off. This is long after the return of intraocular pressure to control values and suggests that monitoring of intraocular tension may not be accurate method of assessing the action of Anectine upon the eye muscles. The mechanism of increased fluid outflow, not muscle relaxation, probably accounts for this lowering of intraocular pressure.

Adolescent↗

Digoxin-induced decrease in intraocular pressure in the cat.

A constant intravenous infusion of digoxin (2 micrograms/kg/min) to alpha-chloralose-anesthetized cats produced a progressive decrease in intraocular pressure with increasing doses of digoxin between 60 micrograms/kg and drug-induced ventricular arrhythmia which occurred at a mean dose of 172 micrograms/kg. Digoxin elicited a 40% decrease in intraocular pressure just prior to ventricular arrhythmia compared to a decrease of only 10% with a control infusion of diluent in the same animal (P less than 0.05). There was no significant difference (P less than 0.1) between changes in blood pressure and heart rate observed in the experimental versus the control infusions. The decrease in intraocular pressure may result from inhibition of the Na-K-ATPase in the ciliary body.

Animals↗

Intraocular pressure change during hemodialysis.

PURPOSE: To evaluate intraocular pressure (IOP) change through hemodialysis and examine other factors to affect IOP change in patients treated with hemodialysis. DESIGN: Prospective, observational case series. METHODS: IOP, blood pressure, and plasma colloid osmotic pressure (COP) were measured in 188 eyes of 95 patients receiving hemodialysis in Nantan General Hospital. RESULTS: IOP significantly decreased after hemodialysis (P = 0.006). Body weight, systolic and diastolic blood pressure also decreased significantly (P < 0.001). COP significantly increased (P < 0.001). Change in IOP correlated negatively with COP change (OD; r = -0.196, OS; r = -0.339) and positively with change in body weight (OD; r = -0.278, OS; r = -0.357). IOP tended to increase after hemodialysis in patients receiving hemodialysis for more than 12 years. CONCLUSIONS: IOP decrease during hemodialysis may be due to COP increase. Patients receiving hemodialysis for a long time are more likely to show IOP increase after hemodialysis.

Adult↗

Effects of mild, moderate and severe exercise on intraocular pressure of sedentary subjects.

Previous studies have shown a reduction in intraocular pressure (IOP) from many forms of exertion, ranging from walking to exhausting exercise. The variability in these results may be due to several factors, such as age, diurnal and seasonal variations, drinking water or coffee before the test, acute hyperglycaemia, and physical fitness. The purpose of the study was to investigate the effects of the common means of exertion on IOP in the same subject, after elimination of above-mentioned factors. The effects of sitting, walking, jogging, and running fast till exhaustion were noted on the IOP of 15 healthy sedentary male volunteers at an interval of 4 days. Intraocular pressures were measured with a Goldmann applanation tonometer at the beginning and at 5th, 20th, 40th, and 60th minutes of the first three tests, but in test 4, only at the beginning and end. Post-exercise measurements were taken after every 10 minutes until IOP returned to pre-exercise levels. The effects of all tests were similar on both eyes. During sitting, walking and jogging, the maximum decreases were (mean +/- SD) 1.20 +/- 0.66, 3.20 +/- 1.19, and 5.07 +/- 1.76 mmHg, and occurred at the 20th, 40th and 60th minutes of the tests respectively. During sitting, walking and jogging, 66.7%, 75% and 68.4% of the maximum decreases occurred after 5 min respectively. After running the mean decrease was 5.7 +/- 1.09 mmHg and the average time of running was 10.53 +/- 2.17 min. In the sitting test, recovery occurred at the end of the test, while in walking, jogging and running tests it occurred after 12.67 +/- 44.48, 30.67 +/- 7.99, and 56.00 +/- 11.21 min, respectively. It is concluded that all forms of exertion decrease IOP. It would seem reasonable, at present, not to discourage patients who have glaucoma from walking; perhaps, on the contrary, it should be encouraged.

Adult↗

Underestimate of tonometric readings after photorefractive keratectomy increases at higher intraocular pressure levels.

PURPOSE: To determine whether tonometric readings of increases in intraocular pressure (IOP) during the water-drinking test (WDT) are affected by variations in central corneal thickness (CCT) induced by photorefractive keratectomy (PRK). METHODS: Data from 30 randomly selected eyes of 30 patients (18 men and 12 women; mean age, +/- SD: 33.9 +/- 7.6 years) undergoing bilateral PRK for myopia (-6.57 +/- 2.39 D) were obtained. Objective refraction, anterior radius of corneal curvature (R), CCT, and IOP measurements at baseline and at different time intervals after ingestion of 1 L of water within 5 minutes, were performed before and 6 months after PRK. All measured IOPs were recalculated by a correction factor for R and CCT and expressed as corrected intraocular pressure (IOPC) measurements. RESULTS: The mean R +/- SD was 7.84 +/- 0.20 and 8.76 +/- 0.34 mm, and the mean CCT was 544.83 +/- 19.69 and 453.97 +/- 29.95 microm, before and after PRK, respectively. The mean IOP at baseline was 15.05 +/- 2.78 and 9.83 +/- 2.56 mm Hg, and during WDT was 18.32 +/- 3.42 and 11.42 +/- 3.10 mm Hg at 10 minutes, 18.59 +/- 2.99 and 11.54 +/- 2.54 mm Hg at 20 minutes, 17.80 +/- 2.85 and 10.87 +/- 2.22 mm Hg at 30 minutes, 16.35 +/- 3.02 and 10.26 +/- 2.21 mm Hg at 45 minutes, and 14.90 +/- 2.52 and 9.81 +/- 2.32 mm Hg at 60 minutes, before and after PRK, respectively. The mean IOPC at baseline was 13.64 +/- 2.33 and 13.05 +/- 2.98 mm Hg, and during WDT was 16.61 +/- 2.77 and 15.08 +/- 3.59 mm Hg at 10 minutes, 16.96 +/- 2.69 and 15.33 +/- 2.96 mm Hg at 20 minutes, 16.10 +/- 2.50 and 14.42 +/- 2.60 mm Hg at 30 minutes, 14.92 +/- 2.72 and 13.62 +/- 2.65 mm Hg at 45 minutes, 13.82 +/- 2.27 and 13.05 +/- 2.55 mm Hg at 60 minutes, before and after excimer laser treatment, respectively. Pre- and postoperative IOPs and percentages of IOP increase differed significantly (P < 0.05), in particular at the peak, as did IOPCs but not the percentages of increase in IOPC, apart from the highest values. CONCLUSIONS: Corneal changes after PRK for myopia may induce an uneven underestimate of the IOP increases. The inadequacy of a correction factor to compensate for CCT and R at high IOP levels indicates that other biomechanical factors may play a role when the cornea is subjected to dynamic actual IOP variation. Such increase of the well-known underestimate of IOP after PRK at higher actual IOPs may have significant clinical implications in tonometric assessment of subjects at risk of glaucomatous damage.

Adult↗

Correlation between finger blood flow and changes in optic nerve head blood flow following therapeutic intraocular pressure reduction.

PURPOSE: To correlate finger blood flow and changes in optic nerve head (ONH) blood flow following therapeutic intraocular pressure (IOP) reduction in open-angle glaucoma (OAG) and ocular hypertension (OHT). METHODS: Seventeen open-angle glaucoma patients and nineteen ocular hypertension patients underwent therapeutic IOP reduction followed by a minimum of 4 weeks of follow-up. Optic nerve head blood flow measurements were obtained by scanning laser Doppler flowmetry using full-field perfusion image analysis. Finger blood flow was measured using the Transonic laser Doppler Flowmeter. Finger blood flow was measured at baseline, after immersion in warm water (40 degrees C) for 2 minutes (Flow Max), and after immersion in cold water (4 degrees C) for 10 seconds (Flow Min). Patients were identified as vasospastic if their Flow Max/Flow Min >7. Statistical comparisons were performed using two-tailed distribution paired T-test and Pearson's correlation factor. RESULTS: For similar mean percentage intraocular pressure reduction, vasospastic patients had greater improvements in rim blood flow than did non-vasospastic patients [+35% versus +13%] (P = 0.01). While there was no difference in rim blood flow changes in the vasospastic versus the non-vasospastic OAG group, the vasospastic ocular hypertension group showed 18% increase in rim blood flow whereas the non-vasospastic ocular hypertension group showed an 8% decrease. A significant negative correlation was also found in the open-angle glaucoma group between rim blood flow change and Flow Max (-0.681, P = 0.003). In contrast, no such correlation was found in the ocular hypertension group (+0.144, P = 0.556). CONCLUSION: OAG patients had a significant negative correlation between changes in rim blood flow and maximum finger Doppler flow. Among ocular hypertension patients, increased rim blood flow was only found in the vasospastic group, though this increase was not statistically significant. These results suggest that open-angle glaucoma and ocular hypertension patients with the most severe vasospastic disease may show the greatest improvements in rim blood flow after sustained intraocular pressure reduction.

Aged↗

Enucleation with stabilization of intraocular pressure in the treatment of uveal melanomas.

The standard surgical technique for enucleation of an eye containing a malignant melanoma of the uvea elevates intraocular pressure markedly and may thereby disseminate tumor cells and cause death. It is possible to enucleate an eye bear a malignant melanoma of the choroid without elevating intraocular pressure to more than 27 mm/Hg by employing a manometric intraocular pressure regulating system and the adjustable cryo-ring. The value of this method of enucleation in diminishing tumor deaths remains unknown.

Adult↗

Prophylactic use of apraclonidine for intraocular pressure increase after Nd:YAG capsulotomies.

We evaluated the prophylactic effect of 1% apraclonidine HCl in controlling the increase in intraocular pressure after Nd:YAG posterior capsulotomy in a large, multicenter double-masked clinical trial. One hundred sixty-four patients were enrolled into the apraclonidine-treated group, and 165 into the vehicle-treated group. The incidence of increase in intraocular pressure (greater than 5 mm Hg) in the apraclonidine-treated group (7%, 11 of 163 patients) was significantly less than that in the vehicle-treated group (39%, 64 of 164 patients). Similarly, the mean maximal change in intraocular pressure in the apraclonidine-treated group (1.3-mm Hg decrease) was significantly different from the increase in the vehicle-treated group (5.3-mm Hg increase). Few adverse reactions were observed. The risk for significant loss of visual function after Nd:YAG laser posterior capsulotomy, combined with the efficacy and relative safety of prophylactic apraclonidine, suggest its addition to the treatment armamentarium.

Adrenergic alpha-Agonists↗

Additive effect of latanoprost and dorzolamide in patients with elevated intraocular pressure.

PURPOSE: To evaluate the additive ocular hypotensive effect of latanoprost and dorzolamide in combination, on intraocular pressure reduction in patients with elevated intraocular pressure (IOP). METHODS: Thirty patients with ocular hypertension or early capsular or primary open-angle glaucoma and elevated IOP were randomly assigned to two parallel treatment groups. The treatment period was twenty days. Fifteen patients (Group 1) received latanoprost once daily during the first ten days and, in addition, dorzolamide three times daily during the second ten days. Fifteen patients (Group 2) received dorzolamide three times daily during the first ten days and, in addition latanoprost, once daily during the second ten days. IOP was measured and conjunctival hyperemia was evaluated. RESULTS: In Group 1, the mean IOP on day 0 was 26.8 mm Hg; on day 10, 18.7 mm Hg; and on day 20, 15.9 mm Hg. In Group 2, the mean IOP on day 0 was 26.3 mm Hg; on day 10, 21.2 mm Hg; and on day 20, 16.1 mm Hg. Both groups had clinically significant IOP-lowering effect on day 10 as compared with baseline day (30.2% and 19.4% respectively) (p<0.01). When dorzolamide was added to latanoprost, the additional IOP reduction was 2.8 mm Hg (15%) (p<0.01) compared with 5.1 mm Hg (24.1%) (p<0.01) when latanoprost was added to dorzolamide. No local serious adverse reactions were observed. A mild but statistically significant increase in conjunctival hyperemia was seen in latanoprost applied patients. CONCLUSIONS: The results showed that latanoprost and dorzolamide can be combined successfully to reduce IOP with their additive effects.

Adult↗

Diurnal intraocular pressure after successful primary laser trabeculoplasty.

In 20 patients who were successfully treated with laser trabeculoplasty as the primary therapy for glaucoma, we measured the intraocular pressure every two hours between 8:00 A.M. and 8:00 P.M. Success was defined as intraocular pressure of 22 mm Hg or less without medication. Of 20 patients, three had open-angle glaucoma and 17 had exfoliative glaucoma. Intraocular pressure was stable with small fluctuations during the daytime.

Aged↗

Evidence for a synergistic interaction between isoprenaline and timolol on intraocular pressure in conscious rabbits.

1. Interaction between topical isoprenaline and timolol on intraocular pressure was studied in conscious rabbits through changes of the dose-response curves. 2. Both drugs caused a dose-dependent fall of intraocular pressure mainly by reducing the aqueous humour formation. 3. When combined, timolol increased the response to submaximal concentrations of isoprenaline as well as EC50 (from 2.06 x 10(-3) M to 3.63 x 10(-3) M) and slope (from 1.21 to 1.89), but peak response to isoprenaline remained unchanged. 4. Discordance between experimental and theoretical additive curves as well as an interaction index smaller than 1 show that the interaction between both drugs is synergistic.

Animals↗

Effects of topical natural ergot alkaloids on intraocular pressure and aqueous humor dynamics in ocular normotensive rabbits.

Although it has been suggested that ergot derivatives may play a role in antiglaucoma therapy, little attention has been paid to the ocular hypotensive action of these drugs. Having previously reported in our laboratory that topical dihydroergocristine decreases intraocular pressure both in ocular normotensive and alpha-chymotrypsin-induced ocular hypertensive rabbits, the aim of the present work was to assess the effect of natural ergot alkaloids, ergocristine, alpha-ergocryptine and ergocornine, on the intraocular pressure and aqueous humor dynamics in ocular normotensive rabbits in order to further explore the ocular actions of these compounds. Intraocular pressure was measured with a pneumatonometer manometrically calibrated for the rabbit eye. Changes in tonographic facility of aqueous humor outflow and rate of aqueous humor inflow were evaluated in anesthetized rabbits. Natural ergot alkaloids were found to reduce intraocular pressure in ocular normotensive eyes in a dose-related fashion. These compounds decreased both tonographic outflow facility and, to a greater extent, aqueous humor inflow, which explains their final hypotensive effect.

Administration, Topical↗

Effect of the Honan intraocular pressure reducer in sub-Tenon's anesthesia.

PURPOSE: To ascertain whether the Honan intraocular pressure reducer (HIPR) has an effect on the preoperative intraocular pressure (IOP), surgeon's assessment of anesthesia, and patients' analgesic experience when sub-Tenon's anesthesia is used for routine cataract surgery. SETTING: Princess Alexandra Eye Pavilion, Edinburgh, Scotland. METHOD: Forty-five eyes of 45 patients having routine phacoemulsification cataract surgery were randomized to receive 10 minutes of ocular compression using the HIPR or no compression after administration of sub-Tenon's anesthesia. The IOP was measured immediately before and immediately and 10 minutes after sub-Tenon's anesthesia administration using a standard technique. One surgeon who was masked to the randomization process performed all injections and completed a questionnaire on aspects of the anesthetic block. Patients scored their level of analgesia during surgery. RESULTS: The mean rise in IOP immediately after administration of sub-Tenon's anesthesia was 1.39 mm Hg +/- 3.91 (SD) (95% confidence interval +0.22 to 2.57; P =.021). In the 22 patients who received compression, there was a mean IOP reduction of 4.20 +/- 2.74 mm Hg at 10 minutes. The mean difference between the compression and no-compression groups at 10 minutes was 4.99 mm Hg (P<.0001). There was no difference in the surgeon's scores for any aspect of the sub-Tenon's anesthesia (P>.05). All patients reported good levels of analgesia. CONCLUSIONS: There was a significant reduction in IOP after compression using the HIPR. However, the rise in IOP after administration of sub-Tenon's anesthesia was small and the use of the HIPR did not make a significant difference in the effectiveness of the anesthesia to the surgeon or patients.

Aged↗

Sustained reduction of intraocular pressure in humans with the calcium channel blocker verapamil.

We investigated the effect of the calcium channel blocker verapamil on intraocular pressure in human volunteers. In the initial trial, 15 subjects with untreated ocular hypertension were tested. After a baseline measurement was obtained with applanation tonometry, a 40-microliter drop of verapamil, 1.25 mg/ml, was instilled in one eye. After 30 minutes, a second reading was taken. In a subsequent trial of 12 untreated ocular hypertensive subjects, the duration of action was determined using the same dose and method of delivery. Results showed that verapamil elicited a mean +/- S.E.M. change in intraocular pressure of -3.8 +/- 0.900 mm Hg in the treated eye, and -1.6 +/- 0.400 mm Hg in the untreated eye. This reduction was statistically different in both eyes (treated eye, P = .0007; untreated eye, P = .005). This decrease in intraocular pressure remained statistically significant when compared to predrug baseline values for up to ten hours.

Administration, Topical↗

An increase in intraocular pressure due to clonidine.

The rise in intraocular pressure (IOP) observed after the administration of clonidine into the carotid arteries was studied in anesthetized rats and cats. This increase of IOP proved to be blocked by the alpha-sympathicolytic agent piperoxane and by the muscle relaxants d-tubocurarine and gallamine. Our experiments suggest that the elevation of IOP after clonidine injection is due to contraction of the eyelids and extraocular muscles. In these tissues alpha-adrenoceptors seem to play a part.

Animals↗

Effect of topical ketanserin administration on intraocular pressure.

The effect of topical ketanserin on intraocular pressure (IOP) in normotensive and hypertensive eyes was evaluated. The study was performed on 10 healthy volunteers and 10 glaucomatous patients. Systolic arterial blood pressure (SBP), diastolic arterial blood pressure (DBP), heart rate (HR), IOP, tonographic outflow facility, pupil diameter, corneal thickness, and tear secretion were recorded at baseline and at 1 hour intervals for 12 hours after topical administration of 0.5% ketanserin or placebo, given in a randomised, double masked, crossover fashion. The alternative treatment was given 1 week later. In all subjects ketanserin significantly lowered IOP, while no variations in SBP, DBP, HR, pupil diameter, corneal thickness, and tear secretion were found. When subjects received placebo no significant variations of IOP occurred. Total outflow facility, measured by conventional tonography, increased significantly after drug administration in all subjects. Ketanserin is effective up to 6 hours in control subjects and 9 hours in glaucomatous patients. The placebo did not induce any change in this component of the aqueous humour dynamic in normal or in glaucomatous eyes. The findings indicate that topical ketanserin might be added to the list of antiglaucomatous agents.

Administration, Topical↗

[Changes in intraocular pressure in response to experimental testing of the amygdaloid complex].

Prolonged electrical stimulation of the lateral amygdaloid nucleus increased the intraocular pressure, the secretion of the intraocular fluid and the amount of proteins and glycosaminoglycans in it. Bilateral electrolysis of the lateral amygdaloid nucleus caused a resistant decrease of the intraocular pressure due to reduced secretion and to increase of the outflow coefficient of the intraocular fluid.

Amygdala↗

Intraocular pressure in exfoliation syndrome.

Two studies, both retrospective, were done at our institution. The first study evaluated 100 consecutive patients with exfoliation (EX) syndrome found as an incidental finding in a private, general ophthalmology practice, to determine the incidence of glaucoma. The second determined the long-term course of EX as it relates to the onset of elevated intraocular pressure (IOP). In the first study, of 124 eyes having EX 78% had normal IOP, 15% had intraocular pressure greater than 22 mm Hg but no cupping or field loss (ocular hypertension or glaucoma suspect), and 7% had glaucoma. In the second study 347 patients who initially had normal IOPs and either unilateral or bilateral EX were followed over time. Elevated IOP developed in 35 patients (44 eyes) during the study. The cumulative probability for eyes with EX to develop elevated intraocular pressure was 5.3% in 5 years and increased to 15.4% in 10 years. These probabilities predict that patients with EX have a higher incidence of developing elevated intraocular pressure than would be expected in patients without EX of similar age.

Aged↗