Howard S. Barnebey

Brimonidine Tartrate: A One-month Dose Response Study

BACKGROUND Brimonidine tartrate is a relatively selective alpha2-agonist that effectively reduces mean intraocular pressure (IOP) and the incidence of IOP spikes after laser trabeculoplasty. The authors were interested in evaluating the dose response of brimonidine when applied topically for a longer duration in patients with elevated IOPs. METHODS The authors conducted a 1-month, multicentered, double-masked, randomized, placebo-controlled, parallel clinical study in 194 patients with ocular hypertension or glaucoma (mean IOP, 25.6 +/- 3.2 mmHg). The authors administered three concentrations of brimonidine (0.08%, 0.2%, and 0.5%) or placebo bilaterally every 12 hours for 1 month. The authors evaluated the following parameters: IOP, heart rate, blood pressure, visual acuity, pupil size, basal tear secretion as well as patient comfort at baseline, day 1, week 1, week 3, and week 4. RESULTS All concentrations of brimonidine significantly reduced IOP, compared to baseline and placebo, at all follow-up visits. Maximum mean IOP decreases from baseline of 20.8%, 27.2%, and 30.1% were observed for the 0.08%, 0.20%, and 0.5% treatment groups, respectively. On days 1 and 21, the 0.2% and 0.5% treatment groups exhibited significantly greater IOP decreases than did the 0.08% group. After the initial steep decline in IOP, the effect decreased slightly and stabilized at day 14 at the level that was maintained throughout the study. The most frequent side effects reported were fatigue and dry mouth. No significant changes in heart rate were reported. Statistically significant decreases in mean blood pressure without clinical symptoms were observed within the 0.2% and 0.5% treatment groups. CONCLUSION Brimonidine 0.2% is well tolerated, efficacious, and shows potential as an agent in the long-term treatment of elevated IOP.

The Efficacy of Brimonidine in Decreasing Elevations in Intraocular Pressure after Laser Trabeculoplasty

PURPOSE The authors explored the empirical dosing requirement for administration of an alpha 2-adrenoceptor agonist, brimonidine, and determined its efficacy in decreasing elevations in intraocular pressure (IOP) after 360 degrees argon laser trabeculoplasty (ALT). METHODS This vehicle-controlled, double-masked, multicenter trial evaluated three dosing regimens of brimonidine. Two hundred thirty-two patients for whom 360 degrees ALT was indicated were randomized into one of four treatment groups: 0.5% brimonidine both before and after ALT; brimonidine before but vehicle after ALT; vehicle before but brimonidine after ALT; or vehicle at both times. RESULTS During the first 3 hours after 360 degrees ALT, the overall incidence of IOP elevations of 5 mmHg or greater was 38% (23 of 60 eyes) in the group receiving vehicle only, and it ranged from 3% to 9% (2 of 62 to 5 of 53 eyes) in the groups receiving any brimonidine treatment. There was little difference in efficacy between the three dosing regimens of brimonidine. Brimonidine was well tolerated by the patients. CONCLUSION Based on this large, controlled, multicenter study, 0.5% brimonidine was an effective agent for reducing elevations in IOP after 360 degrees ALT. Only one dose, administered either before or after 360 degrees ALT, was required.

Continuous visual field test supervision may not always be necessary

OBJECTIVE To assess the effect of supervision on computerized visual field (VF) performance and to determine what patient characteristics predict poor unsupervised performance. DESIGN Randomized, crossover, cross-sectional, clinical trial. PARTICIPANTS Two hundred unselected patients with definite or suspect glaucoma or neuro-ophthalmic VF indication participated. INTERVENTION All patients completed two 30-2 tests of one eye on a Humphrey perimeter, one with continuous active technician supervision and one without supervision after the initial 2 minutes of the test. MAIN OUTCOME MEASURES Visual field reliability and global VF indices were measured. RESULTS Supervision had a positive effect on overall reliability (P = 0.04) but not on individual reliability parameters or any of the global VF indices. There was no difference between Humphrey Field Analyzers I and II in the need for supervision. Predictors of need for supervision were low educational level and a prior test result with false-positive responses. Predictors of an unreliable test were advanced age and a prior test with a high proportion of fixation losses. CONCLUSION Supervision is necessary for those with risk factors for unsatisfactory perimetry such as advanced age, low level of formal education, and prior test results with false-positive responses or high fixation losses; in the remainder, omission of supervision can be considered.