Brimonidine Tartrate Ophthalmic Solution Research Articles

Charles Bonnet Syndrome Precipitated by Brimonidine Tartrate

Charles Bonnet Syndrome (CBS) induced by brimonidine tartrate ophthalmic solution has rarely been reported. CBS is a condition characterized by visual hallucinations in patients with vision loss and clear cognition. This condition is more prevalent in the elderly population, between the ages of 75 and 84 years old.

Patient Factors Influencing Intraocular Penetration of Brimonidine-Related Eye Drops in Adults: A Post Hoc Pooled Analysis.

The factors related to the ocular penetration of drugs after the administration of eye drops in humans have not been examined in detail. Therefore, this study assessed the influence of patient factors on the intraocular penetration of eye drops. A pooled analysis was performed on the data of 42 participants from three studies to evaluate the ocular pharmacokinetics in humans after the topical application of brimonidine-related eye drops. The patients were scheduled for vitrectomy and received brimonidine-related eye drops (0.1% brimonidine tartrate ophthalmic solution, 0.1% brimonidine tartrate and 0.5% timolol fixed-combination ophthalmic solution, or 0.1% brimonidine tartrate and 1% brinzolamide fixed-combination suspension) twice daily for 1 week. We analyzed the effects of patient factors (sex, the presence or absence of lens, age, corneal thickness, corneal endothelial cell density, tear secretion, eye axial length, height, weight and body mass index [BMI]) on brimonidine, timolol and brinzolamide concentrations in the aqueous and vitreous humor after topical application. The drug concentrations in the aqueous and vitreous humor were not significantly different, regardless of sex or the presence or absence of lens. Age correlated positively with brimonidine (r = 0.3948, p = 0.012) and brinzolamide (r = 0.6809, p = 0.030) concentrations in the aqueous humor; the correlation with timolol showed a trend towards significance (r = 0.6425, p = 0.086). Corneal thickness, corneal endothelial cell density, tear secretion, eye axial length, height and BMI did not correlate with the drug concentrations in the aqueous or vitreous humor. Timolol concentration in the vitreous humor was negatively correlated with weight (r = - 0.8333, p = 0.010). The findings of this study emphasize the necessity of considering individual differences in ocular pharmacokinetics during drug therapy (formulation design of the eye drops and dose regimen).

Brimonidine tartrate ophthalmic solution 0.025% for redness relief: an overview of safety and efficacy

ABSTRACT Introduction Ocular redness, or conjunctival hyperemia, is a common ophthalmic sign associated with reduced quality of life. For redness without apparent underlying pathology, topical ophthalmic decongestants have been widely used. Areas covered Brimonidine tartrate was approved in 2017 as a topical vasoconstrictor at a 0.025% concentration for relief of ocular redness. Since then, investigators have reported on efficacy and safety findings from studies evaluating low-dose brimonidine for reducing ocular redness. Expert opinion Brimonidine is highly selective for α2-adrenergic receptors. Clinical trials have so far shown that the drug in low doses significantly reduces ocular redness in comparison to vehicle for up to 8 hours. Brimonidine-treated eyes did not present side effects of other vasoconstrictors, such as hypotension, cardiac arrhythmia, or drowsiness. Ocular adverse events, such as allergic reactions and redness rebound, were also minimal. In this review, we examine in detail published literature on the mechanism of brimonidine tartrate and its efficacy and safety in relieving conjunctival hyperemia.

Ocular and systemic pharmacokinetics of brimonidine and brinzolamide after topical administration in rabbits: comparison between fixed-combination and single-drug formulations

ABSTRACT Aim The aim of this study was to compare the ocular and systemic absorption of brimonidine (BMD) and brinzolamide (BZM) in rabbits after the topical administration of a fixed-combination ophthalmic suspension of 0.1% BMD tartrate and 1% BZM (FCBB) with that after the administration of the respective single-drug formulations. Materials and Methods Ocular and systemic drug absorption was estimated by determining BMD and BZM concentrations in the aqueous humor, retina/choroid, vitreous body, and blood/plasma by liquid chromatography/tandem mass spectrometry after the administration of FCBB, 0.1% BMD tartrate ophthalmic solution (0.1% BMD), or 1% BZM ophthalmic suspension (1% BZM) to rabbits. Results In concomitant administration, instilling 0.1% BMD and 1% BZM successively without interval lowered aqueous humor concentrations of both drugs compared to those observed with a 5-min interval. After FCBB administration, BMD and BZM concentrations in the aqueous humor were comparable with those observed after the administration of 0.1% BMD and 1% BZM, whereas BMD concentrations in posterior ocular tissues were equal to or higher than those observed after 0.1% BMD. Plasma BMD concentrations following the administration of FCBB were 0.8-fold lower than those after 0.1% BMD; no remarkable differences were observed in blood BZM concentrations for both formulations. Conclusions FCBB achieved drug distribution in the aqueous humor and systemic exposure that were comparable to those for the single-drug formulations. The viscosity of FCBB may increase BMD distribution in the retina/choroid. The administration interval affects ocular drug absorption with the concomitant administration of 0.1% BMD and 1% BZM, which can be overcome by using the fixed-combination of both drugs.

Ocular and Systemic Pharmacokinetics of Brimonidine and Timolol After Topical Administration in Rabbits: Comparison Between Fixed-Combination and Single Drugs.

IntroductionThis study was aimed to compare ocular tissue distribution and systemic exposure of brimonidine and timolol after single topical administration to rabbits of fixed-combination ophthalmic solution of 0.1% brimonidine tartrate and 0.5% timolol and single drugs (0.1% brimonidine tartrate ophthalmic solution or 0.5% timolol ophthalmic solution) or concomitant administration of single drugs.MethodsRabbits were treated with a single topical administration of each ophthalmic solution or concomitant administration of single drugs. For concomitant administration, 0.1% brimonidine tartrate was administered after 0.5% timolol instillation successively within 10 s (without interval) or with 5-min intervals. Brimonidine and timolol concentrations in the aqueous humor, retina/choroid, vitreous body, and plasma were determined with liquid chromatography-tandem mass spectrometry.ResultsThe area under the curve values of both drugs in the aqueous humor after fixed-combination administration were comparable to those after concomitant administration. The value of brimonidine was comparable to that after 0.1% brimonidine tartrate administration, whereas the value of timolol was 1.6-fold higher than that after 0.5% timolol administration. The plasma area under the curve value of brimonidine did not differ between fixed-combination and single-drug administrations, but that of timolol was higher after fixed-combination administration than after single-drug administration. Similar concentration-time curves of brimonidine were observed in the posterior ocular tissues in all groups. For concomitant administration, both drug concentrations in the aqueous humor without an administration interval were lower than those with 5-min intervals.ConclusionThere was no difference in the effect of formulation compositions on ocular and systemic pharmacokinetics among the ophthalmic solutions, but brimonidine may alter the ocular and systemic absorption of timolol, which is possibly due to its pharmacologic action. We demonstrated the importance of an administration interval in the concomitant administration of these drugs. This concern could be avoided by using a fixed combination of brimonidine and timolol.

Effect of Solution pH on Distribution of Ophthalmically Administered Brimonidine in Posterior Ocular Tissues in Pigmented Rabbits.

IntroductionBrimonidine bioavailability in the aqueous humor depends on the solution pH following topical administration. The purpose of this study was to investigate the effect of solution pH on brimonidine distribution in the posterior ocular tissues in pigmented rabbits.MethodsThe anterior retina/choroid, posterior retina/choroid, and vitreous body of pigmented rabbits were collected 0.67, 1.5, 3, 6, 12, 24, 168, and 360 h after the administration of a single topical dose of 0.2% brimonidine tartrate ophthalmic solution, pH 6.4 (Alphagan®; Allergan Inc., Irvine, CA, USA). Brimonidine concentrations in these tissues were quantified using liquid chromatography/tandem mass spectrometry. Pharmacokinetic parameters were determined using noncompartmental analysis, and the results were compared with tissues from eyes administered 0.1% brimonidine tartrate ophthalmic solution, pH 7.3 (Aiphagan®; Senju Pharmaceutical Co., Ltd., Osaka, Japan) in our previous study conducted using the same procedure.ResultsTopically applied brimonidine was distributed rapidly into the posterior tissues of the eye after a single ophthalmic administration of the 0.2% ophthalmic solution. The areas under the curve from time 0 to 360 h following dosing with the 0.2% ophthalmic solution were 500,000, 14,300, and 28.7 ng h/g in the anterior and posterior retina/choroid, and vitreous body, respectively.ConclusionThe differences in the areas under the curve between two ophthalmic solutions were less than the difference in drug concentrations between these two products in any tissues. This finding indicates that the change in the solution pH from 6.4 to 7.3 increases brimonidine bioavailability into the posterior ocular tissues similarly as into the aqueous humor.FundingSenju Pharmaceutical Co., Ltd.

Low‐dose brimonidine for relief of ocular redness: integrated analysis of four clinical trials

BackgroundThe aim of this study was to provide an integrated analysis of safety and efficacy data for brimonidine tartrate ophthalmic solution 0.025 per cent (low‐dose; Bausch & Lomb Incorporated), a topical vasoconstrictor for relief of ocular redness.MethodsIntegrated efficacy data from two randomised, double‐masked, vehicle‐controlled studies in subjects with ocular redness as well as safety data from the two efficacy studies, a vehicle‐controlled safety study, and a pharmacokinetic study were analysed. Efficacy outcomes analysed included investigator‐assessed ocular redness (scale, 0–4) before treatment instillation and at five to 240-minutes post‐instillation on Day 1, at five-minutes post‐instillation on Days 15 and 29, and one-week after treatment discontinuation (Day 36), and redness self‐assessed by subjects recorded daily in diaries. Safety assessments included adverse events, ophthalmic examinations, and rebound redness upon treatment discontinuation. Drop comfort (scale, 0–10) was a tolerability measure.ResultsThe efficacy population included 117 subjects (brimonidine, n = 78; vehicle, n = 39). The safety population included 635 subjects (brimonidine, n = 426; vehicle, n = 209). Investigator‐assessed ocular redness was significantly lower with brimonidine versus vehicle at all post‐instillation time points on Day 1 (mean change from pre‐instillation of −1.4-units for brimonidine and −0.2-units for vehicle; p < 0.0001). Subject‐assessed ocular redness was also significantly lower with brimonidine versus vehicle (mean treatment difference in average daily ratings of −0.9; p < 0.0001). There was no evidence of tachyphylaxis through Day 29 and rebound redness was rare. Incidence of ocular adverse events was low, the most common being reduced visual acuity (brimonidine, 4.0-per cent; vehicle, 4.3-per cent) and conjunctival hyperaemia (2.6 and 2.9-per cent, respectively). Both brimonidine and vehicle were rated as very comfortable (mean post‐instillation scores, 0.4–0.5).ConclusionIn this integrated analysis, low‐dose brimonidine significantly reduced ocular redness with no tachyphylaxis, and minimal rebound redness, and was generally safe and well tolerated.

Buzzing Sympathetic Nerves: A New Test to Enhance Anisocoria in Horner's Syndrome.

Introduction: Patients with suspected Horner's syndrome having equivocal pupil dilation lag and pharmacologic testing may undergo unnecessary MR imaging and work up in the case of false positive pupil test results. Our goal was to increase the diagnostic accuracy of pupillometry by accentuating the inter-ocular asymmetry of sympathetic innervation to the iris dilator with surface electrical stimulation of the median nerve using a standard electromyography machine. We hypothesized that an accentuated difference in sympathetic response between the two eyes would facilitate the diagnosis of Horner's syndrome.Methods: Eighteen patients with pharmacologically proven Horner's syndrome were compared to ten healthy volunteers tested before and after monocular instillation of 0.2% brimonidine tartrate ophthalmic solution to induce pharmacological Horner's syndrome. Pupillary responses were measured with binocular pupillometry in response to sympathetic activation by electrical stimulation of the median nerve in darkness and at various times after extinction of a light stimulus. Sudomotor sympathetic responses from the palm of the stimulated arm were recorded simultaneously.Results: In subjects with Horner's syndrome and pharmacologically induced unilateral sympathetic deficit, electrical stimulation in combination with the extinction of light greatly enhanced the anisocoria during the evoked pupil dilation, while there was no significant increase in anisocoria in healthy subjects. The asymmetry of the sympathetic response was greatest when the electrical stimulus was given 2 s after termination of the light or under constant low light conditions. When given 2 s after termination of light, the electrical stimulation increased the mean anisocoria from 1.0 to 1.2 mm in Horner's syndrome (p = 0.01) compared to 0.22–0.26 mm in healthy subjects (p = 0.1). In all subjects, the maximal anisocoria induced by the electrical stimulation appeared within a 2 s interval after the stimulus. Correspondingly, the largest change in anisocoria between light and dark without electrical stimulation was seen between 3 and 4 s after light-off. While stronger triple stimulation further enhanced the anisocoria, it was less well tolerated.Conclusions: Electrical stimulation 2 s after light-off greatly enhances the sensitivity of pupillometry for diagnosing Horner's syndrome. This new method may help to rule in or rule out a questionable Horner's syndrome, especially if the results of topical pharmacological testing are inconclusive.

Evaluation of Efficacy and Safety of Brimonidine Tartrate Ophthalmic Solution, 0.025% for Treatment of Ocular Redness

ABSTRACTPurpose/Aims: This study assessed the efficacy and safety of brimonidine tartrate ophthalmic solution, 0.025% for treating ocular redness in adult subjects.Materials and Methods: This was a single-center, double-masked, randomized, vehicle-controlled, parallel-group study in subjects ≥40 years, with ocular redness. Subjects were randomized 2:1 to brimonidine or vehicle, instilled QID for four weeks. Subjects completed four visits, the last occurring one week after treatment discontinuation. The investigator assessed ocular redness on a scale of 0–4 pre-instillation and 5–240 minutes post-instillation on Day 0, pre-instillation and 5 minutes post-instillation on Days 14 and 28, and on Day35; subjects assessed redness in diaries throughout the 28-day treatment period and following treatment discontinuation. Safety assessments included adverse events (AEs), rebound redness on treatment discontinuation, comprehensive ophthalmic exams, and vital signs. Drop comfort was assessed upon instillation, and 30 seconds and 1 minute post-instillation at Day 0.Results: Fifty-seven subjects (brimonidine, n = 38; vehicle, n = 19) were randomized. Investigator-assessed ocular redness was significantly reduced with brimonidine across the entire post-instillation time period (overall treatment difference: −1.37; P < 0.0001) and at all individual time points (P < 0.0001). Subject-assessed ocular redness was also significantly lower with brimonidine (P ≤ 0.0005). No tachyphylaxis was evident. There were few ocular AEs, all mild to moderate in severity, and no redness rebound was observed upon brimonidine discontinuation. There were no effects on any safety measures, and both brimonidine and its vehicle were reported to be very comfortable.Conclusions: Brimonidine 0.025% appeared safe, well tolerated, and reduced ocular redness for at least 4 hours. No tachyphylaxis or rebound redness upon treatment discontinuation was observed.

Sedative and physiological effects of brimonidine tartrate ophthalmic solution in healthy cats

ObjectiveTo determine the effects of brimonidine tartrate ophthalmic solution on sedation, heart rate (HR), respiratory frequency (fR), rectal temperature (RT) and noninvasive mean arterial pressure (MAP) in healthy cats. Study designRandomized, blinded crossover study, with 1 week washout between treatments. AnimalsSix healthy purpose-bred cats. MethodsBrimonidine tartrate ophthalmic solution 0.1% (one or two drops; 58.6 ± 3.3 μg per drop) or a control solution (artificial tear solution) was administered to six healthy cats. Behavioural observations and measurements of HR, fR, RT and MAP were recorded before and at 30, 60, 90, 120, 180, 240, 300 and 360 minutes after topical administration. Behavioural scores were analysed using Friedman’s test for repeated measures to evaluate the time effect in each treatment and treatment effect at each time point. Physiological variables (HR, fR, RT and MAP) were analysed using two-way analysis of variance for repeated measures to evaluate the time and treatment effects. The level of significance was set at p < 0.05. ResultsDose-dependent behavioural and physiological responses were noted. A dose of two drops of brimonidine resulted in sedation in the cats and decreased HR and MAP. Significant sedative effects occurred between 30 and 120 minutes and for physiological responses up to 360 minutes. The most frequent adverse reaction was vomiting, occurring within 40 minutes in all six cats administered two drops and five of the six cats administered one drop of brimonidine. Conclusions and clinical relevanceThe results demonstrated that ocular administration of brimonidine 0.1% ophthalmic solution induced sedation in cats and some cardiovascular effects usually associated with α2-adrenoceptor agonists. Further studies should be performed to determine clinical applications for this agent in cats.

The Relationship of Brimonidine Concentration in Vitreous Body to the Free Concentration in Retina/Choroid Following Topical Administration in Pigmented Rabbits

ABSTRACTPurpose: Several studies showed that repeated topical administration of brimonidine tartrate ophthalmic solution reached the human vitreous concentration above 2 nM, which is the concentration necessary to activate the α2-adrenergic receptor. The purpose of this study was to elucidate the relationship of the brimonidine concentration in the vitreous body to the free concentration in the retina/choroid which is the target site of brimonidine on neuroprotective effect after topical administration.Materials and methods: Brimonidine concentrations in the eye tissues of pigmented rabbits were determined following single ocular administration of 0.1% brimonidine tartrate ophthalmic solution at pH 7.3. Binding affinity of brimonidine to melanin and melanin content in the retina/choroid of pigmented rabbits was also examined. The concentration of free brimonidine which did not bind to melanin in the retina/choroid was calculated using the binding parameters to melanin.Results: Topically applied brimonidine rapidly distributed to intraocular tissues. The elimination rate from melanin-containing tissues such as the iris/ciliary body and retina/choroid was slower than the aqueous humor and vitreous body in pigmented rabbits. In both the anterior and posterior retina/choroid, the free brimonidine concentrations were over 100-fold lower than the total concentrations. The concentrations in the vitreous body closely matched to the free concentrations in the posterior retina/choroid. Simulated free concentrations in the posterior retina/choroid were gradually increased when 0.1% solution was instilled twice daily.Conclusion: The present data indicated that the brimonidine concentration in the vitreous body was comparable to the free concentration in the posterior retina/choroid. This suggests that the vitreous concentration can be a surrogate indicator of the free brimonidine concentration in the posterior retina/choroid. From the present findings, it is expected that multiple instillation of brimonidine tartrate ophthalmic solution may produce the sufficient free concentration for activation of the α2-adrenergic receptor in the retina/choroid in human.

Comparative pharmacokinetics and bioavailability of brimonidine following ocular and dermal administration of brimonidine tartrate ophthalmic solution and gel in patients with moderate-to-severe facial erythema associated with rosacea

Persistent facial erythema is the most common primary pathological feature of rosacea, the only treatment for which is brimonidine tartrate (BT) gel. To assess the relative bioavailability of topical BT gel in comparison with the ophthalmic BT solution. A pharmacokinetic study was conducted to compare intraindividual systemic exposures after dermal application of BT gel (0·07%, 0·18% and 0·5%) under maximal use conditions in patients with moderate-to-severe facial erythema associated with rosacea, and administration of BT ophthalmic solution 0·2%. Patients who received BT ophthalmic solution 0·2% three times a day for 1 day had a mean Cmax of 54 ± 28 pg mL(-1) and a mean 0-24-h area under the curve (AUC0-24 h ) of 568 ± 277 pg h mL(-1) . Topical application of BT gel for 29 days resulted in quantifiable systemic exposure in 22%, 48%, 71% and 79% of patients who received BT gel 0·07% twice daily, 0·18% once daily, 0·18% twice daily and 0·5% once daily, respectively. The mean Cmax values for the BT gels ranged between 13 and 25 pg mL(-1) , and mean AUC0-24 h values ranged between 42 and 290 pg h mL(-1) . Systemic exposure increased with applied dose, with no drug accumulation for the duration of treatment. The systemic exposure observed with the highest dose of BT gel (0·5% once daily) was significantly lower than the systemic levels observed for the ophthalmic solution. 0·2% apply for all the concentrations. The systemic safety profile of BT gel may be considered better than that of the ophthalmic solution.

Studying the Effect of Iris Mechanics on the Pupillary Light Reflex Using Brimonidine-Induced Anisocoria

To study and correct for the limiting effect of iris mechanics on the amplitude of light-evoked pupil contractions in order to derive a more clinically accurate assessment of afferent input to the visual system. Transient pupil responses were recorded to a series of 1-second red Ganzfeld light stimuli with a stepwise increase in stimulus intensity using a binocular infrared computerized pupillometer. One eye of eight healthy subjects was treated with 0.2% brimonidine tartrate ophthalmic solution to induce pupil size reduction. The amount of pupil contraction as a function of stimulus intensity was compared between the brimonidine-treated, miotic eye and the untreated eye. BRIMONIDINE TREATMENT PRODUCED SIGNIFICANT REDUCTION IN PUPIL SIZE IN HEALTHY SUBJECTS (MEAN REDUCTION IN PUPIL SIZE: 1.78 ± 0.35 mm, P < 0.05). For increasing light intensity, the treated pupil started to show reduced pupil contractions compared with the contralateral untreated pupil when the peak of pupil contraction reached an average pupil size of 3.25 ± 0.61 mm (range, 2.38-4.44 mm). When measured by percent pupil contraction (contraction amplitude/baseline pupil diameter), the pupil response as a function of stimulus intensity in the treated, miotic eye did not differ from that in the untreated eye. Iris mechanics limits the amount of pupil contraction and can act to reduce the assessed neuronal integration of the pupil light reflex. Pupil response assessed by using percent contraction amplitude is least affected by mechanical effects and provides a more accurate approximation of afferent input.

A Stability-Indicating Assay of Brimonidine Tartrate Ophthalmic Solution and Stress Testing Using HILIC

A stability-indicating hydrophilic interaction liquid chromatography (HILIC) method has been developed and validated for the quantitative determination of Brimonidine tartrate (BT) formulated as an ophthalmic solution. Isocratic separation was achieved using an acetonitrile-buffer mixture (92:8, v/v) at pH 7.1 on an unmodified silica column (250 × 4.6 mm, 5 μm). The drug was subjected to oxidative, hydrolytic, photolytic and thermal stress conditions and complete separation was achieved for the parent compound and degradation products. The influence of acetonitrile, pH and ionic strength of the buffer was studied. Linearity range and recoveries for BT were 100–400 μg mL−1 and 100.12%, respectively. The method was validated for BT and indicated that the method was sufficiently sensitive with a limit of detection at 0.005 μg mL−1 and a limit of quantitation at 0.02 μg mL−1, respectively.

Effect of brimonidine tartrate 0.15% on night-vision difficulty and contrast testing after refractive surgery

To evaluate the efficacy of brimonidine tartrate ophthalmic solution 0.15% in patients with night-vision difficulties after laser refractive surgery. Center for Refractive Surgery, Walter Reed Army Medical Center, Washington, District of Columbia, USA. Six patients with significant night-vision complaints after refractive surgery were enrolled in this study after other treatable causes of night-vision difficulty such as residual refractive error and dry eye were excluded. Low-contrast visual acuity (LCVA) over a range of contrasts (1.25% to 25%) and small letter contrast sensitivity were tested at photopic (100 cd/m(2)) and mesopic (1 cd/m(2)) luminance levels, with and without a standard glare source. Testing was performed before brimonidine tartrate ophthalmic solution 0.15% was administered. Measurements were repeated 1 hour and 1 month after the use of brimonidine tartrate. One hour after using brimonidine tartrate 0.15% solution, patients had significant improvement in LCVA, LCVA with glare, and contrast sensitivity. After 1 month of treatment, all 6 patients reported subjective improvement in night vision and there was a significant difference in performance in mesopic LCVA and mesopic LCVA with glare. The mean pupil size before administration of brimonidine tartrate ophthalmic solution 0.15% was 6.44 mm +/- 1.11 (SD). Pupil size 1 hour after instillation had decreased to 4.53 +/- 1.27 mm and at 1 month had increased to 6.50 +/- 0.94 mm. Brimonidine tartrate ophthalmic solution 0.15% improved contrast sensitivity and acuity and decreased night-vision difficulty for up to 1 month in patients with significant complaints after refractive surgery.

Effect of brimonidine tartrate ophthalmic solution 0.2% on pupil size in normal eyes under different luminance conditions

Abstract Purpose To evaluate the effect of brimonidine tartrate ophthalmic solution 0.2% (Alphagan®) on pupil size in normal eyes. Three luminance conditions were used to assess the potential use of brimonidine in postoperative refractive patients who experience nighttime vision problems related to large pupil size. Setting McDonald Eye Associates, Fayetteville, Arkansas, USA. Methods Pupil size was measured in 16 eyes of 16 participants with the Colvard pupillometer under 3 luminance conditions. One drop of brimonidine 0.2% was administered to each patient. Pupil size was then measured using the same technique 30 minutes and 4 and 6 hours after drop administration. Results Under scotopic conditions, 100% of the pupils showed significant miosis at 30 minutes ( P P > .05). The pupil size in 5 eyes (31.2%) was not affected at 30 minutes or 4 or 6 hours. At 6 hours, 15 eyes (93.8%) had returned to their preinstillation size. Conclusion Brimonidine tartrate 0.2% had a significant effect in decreasing pupil size under scotopic conditions. The results indicate that the drug can decrease night-vision difficulties such as halos, star bursts, glare, and monocular diplopia in postoperative refractive patients.

Effect of brimonidine tartrate ophthalmic solution 0.2% on pupil size in normal eyes under different luminance conditions

Purpose To evaluate the effect of brimonidine tartrate ophthalmic solution 0.2% (Alphagan®) on pupil size in normal eyes. Three luminance conditions were used to assess the potential use of brimonidine in postoperative refractive patients who experience nighttime vision problems related to large pupil size. Setting McDonald Eye Associates, Fayetteville, Arkansas, USA. Methods Pupil size was measured in 16 eyes of 16 participants with the Colvard pupillometer under 3 luminance conditions. One drop of brimonidine 0.2% was administered to each patient. Pupil size was then measured using the same technique 30 minutes and 4 and 6 hours after drop administration. Results Under scotopic conditions, 100% of the pupils showed significant miosis at 30 minutes ( P < .05). The effect continued in all eyes for 4 hours. At 6 hours, a miotic effect was still present in 81.3%. However, under photopic luminance, there was no significant effect on pupil size in all 16 eyes ( P > .05). The pupil size in 5 eyes (31.2%) was not affected at 30 minutes or 4 or 6 hours. At 6 hours, 15 eyes (93.8%) had returned to their preinstillation size. Conclusion Brimonidine tartrate 0.2% had a significant effect in decreasing pupil size under scotopic conditions. The results indicate that the drug can decrease night-vision difficulties such as halos, star bursts, glare, and monocular diplopia in postoperative refractive patients.