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

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

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.

Evaluation of the association between macular damage and disability glare in patients with advanced glaucoma

PURPOSE

This study aimed to investigate the factors associated with disability glare in patients with advanced glaucoma and evaluate the impact of disability glare on the vision-related quality of life.

METHODS

We prospectively studied 225 eyes (225 patients) with advanced glaucoma. The visual function was evaluated using the 10-2 and 24-2 Humphrey visual field (VF) (Dublin, California) and contrast sensitivity test. Structural parameters were obtained using RTVue optical coherence tomography and angiography (Fremont, California). Significant loss of macular vessel density (mVD) was defined as VD < 30%. Each participant completed the National Eye Institute Visual Function Questionnaire 25 (NEI-VFQ-25) and questions regarding subjective symptoms of glare.

RESULTS

Fifty-six patients (24.9%) experienced glare and had a lower NEI-VFQ-25 composite score (P = 0.017). The average retinal nerve fiber layer and ganglion cell complex thickness and mean deviation (MD) in the 24-2 VF test were not associated with glare. Significant superior or inferior mVD loss (P < 0.001; odds ratio [OR], 3.45; and 95% confidence interval [CI], 1.83-6.55), lower logarithmic contrast sensitivity at 0.75 cycles/degree (P < 0.001; OR, 0.27; and 95% CI, 0.13-0.56), and worse MD in the 10-2 VF test (P < 0.001; OR, 0.93; and 95% CI, 0.89-0.97) showed an association with glare.

CONCLUSION

In advanced glaucoma, central VF defect and mVD loss are associated with disability glare, which negatively impacts vision-related quality of life.

Effect of over-the-counter brimonidine tartrate 0.025% ophthalmic solution on pupil size in healthy adults

Purpose

To evaluate the effect of brimonidine tartrate 0.025% ophthalmic solution on pupil size under scotopic conditions in healthy adults

Methods

Pupil size was measured in 56 eyes of 28 volunteer participants using a pupillometer under scotopic conditions. Age, gender, and iris color were recorded. Subjects using any ophthalmic medications other than artificial tears were excluded. The pupil size was subsequently measured again under scotopic conditions 60 min after instillation of brimonidine tartrate 0.025% ophthalmic solution.

Results

Statistically significant miosis was seen after instillation of brimonidine tartrate 0.025% (p = 0.04). Average pupil size prior to brimonidine 0.025% instillation was 7.28 ± 1.05 mm, and average pupil size after instillation of brimonidine 0.025% was 6.36 ± 1.68 mm, a reduction of − 23.7% in pupil area. Subjects with light irides demonstrated a greater miotic effect than subjects with dark irides (1.55 mm vs. 0.67 mm, p < 0.0001), with a pupil area reduction of − 37.6% and − 17.4%, respectively. The amount of miosis was independent of initial pupil size.

Conclusions

Brimonidine tartrate 0.025% causes significant miosis in scotopic settings, although the effect is not as great in darker colored eyes. Further studies are needed to determine the latency and duration of the effect and whether the amount of miosis is clinically significant.

Effect of the EVO+ Visian Phakic Implantable Collamer Lens on Visual Performance and Quality of Vision and Life

PURPOSE

To assess the effect of EVO+ (V5) Visian implantable collamer lens implantation on mesopic visual performance, quality of vision (QoV), and quality of life (QoL).

DESIGN

Prospective interventional case series.

METHODS

Thirty-six eyes of 36 participants who underwent EVO+ implantation for myopia were evaluated preoperatively and at postoperative visits at 1 week and 1, 3, and 6 months. Visual acuity (VA) and mesopic contrast sensitivity (CS) with and without halogen- and xenon-type glare sources were evaluated at each visit. Subjective QoV was assessed with the QoV questionnaire and QoL assessed with the Quality of Life Impact of Refractive Correction (QIRC) questionnaire at each visit. Ring-shaped dysphotopsia was also assessed at each postoperative visit. Linear, cumulative link and logit mixed models were fitted to analyze the effect of the EVO+.

RESULTS

Following EVO+ implantation, VA significantly (P ≤ .012) improved at the 4 postoperative visits. Mesopic CS progressively improved at 1, 3, and 6 months postoperatively (P ≤ .012). Halogen glare CS decreased at 1 week and halogen and xenon glare CS improved at 6 months (P ≤ .016). Photostress recovery time after halogen glare improved at 3 and 6 months (P ≤ .004). QoV scores improved at 1 week and 3 and 6 months (P ≤ .001). QIRC scores improved postoperatively (P < .001). Ring-shaped dysphotopsia decreased at 3 and 6 months (P ≤ .007).

CONCLUSIONS

EVO+ implantation provides good mesopic visual performance, QoV, and QoL during up to 6 months follow-up. Some activities performed under mesopic conditions with glare sources may be affected during the first postoperative week. Ring-shaped dysphotopsia is negligibly bothersome 6 months after surgery.

Effects of a Single Dose of Topical Brimonidine 0.15% on Anterior Segment Morphology, Pupil Characteristics, and Choroidal Thickness in Healthy Subjects

PURPOSE

To investigate the effects of a single dose of brimonidine 0.15% on anterior segment morphology, pupil characteristics, and choroidal blood flow in treated and untreated eyes of healthy subjects and to compare the results obtained with those in another healthy volunteer group.

METHODS

Participants were classified as study and control groups. The eyes in the study group were randomized. Only one eye received one drop of brimonidine (treated eyes), and the contralateral eye received single dose of sodium hyaluronate (untreated eyes). In addition, only right eyes of control subjects, who had single dose of sodium hyaluronate to both eyes, were analyzed (control eyes). Anterior segment parameters including central corneal thickness (CCT), aqueous depth, anterior chamber volume, iridocorneal angle (ICA), horizontal anterior chamber diameter, and pupil measurements including scotopic, mesopic, photopic, and dynamic pupil diameters (PDs) were performed with Sirius Scheimpflug camera. Choroidal thickness (CT) measurements were taken with optical coherence tomography. These measurements were taken at baseline and repeated 1 hour after the dosing.

RESULTS

Only the treated eyes had significantly thicker CCT and wider ICA values after instillation of brimonidine. Static and dynamic PD values of treated eyes and even untreated eyes significantly decreased after brimonidine. However, brimonidine has no significant effect on CT measurements.

CONCLUSION

A single dose of brimonidine causes thickening in CCT and widening in ICA values in treated eyes. In addition, it has significant effect to decrease the scotopic, mesopic, photopic, and dynamic PD values in treated and even contralateral eyes while has no effect on choroidal blood flow.

Effect of brimonidine tartrate 0.2% ophthalmic solution on visual quality after implantable collamer lens implantation with a central hole

PURPOSE

To investigate the effect of brimonidine tartrate 0.2% on visual quality after implantable collamer lens with a central hole (ICL V4c).

METHODS

This study comprised 59 consecutive patients implanted with an ICL V4c. Brimonidine was administered randomly into one eye of the patients with symptomatic glare or halos 1 week postoperatively and the contralateral eye with artificial tears as the control group. Visual quality (measured by a optical quality analysis system), pupil size and refraction under scotopic light conditions were measured before and 0.5, 1.5, 3 and 6 h after administration of brimonidine. A symptom questionnaire was also evaluated.

RESULTS

The visual quality improved and reached its maximum value, and the scotopic pupil size reached its minimum value 1.5 h after brimonidine administration, with a statistically significant difference seen from 0.5 to 3 h compared to baseline. No changes in refraction were seen after brimonidine. The questionnaire showed that symptoms of glare or halos could be eliminated after brimonidine in 58% of patients, be alleviated in 37% of patients and be unchanged in 5% of patient. However, 10% of patients experienced conjunctival congestion and some patients experienced reduced drug efficacy 1 month after treatment.

CONCLUSION

Brimonidine can be used to improve night visual quality in early postoperative period after ICL V4c implantation. It helps patients to quickly adapt to the glare or halos.

Time-course of the visual Impact on presbyopes of a low dose miotic

PURPOSE

To examine the pupil and visual impact of a single early morning drop of a low concentration miotic.

METHODS

Pupil size, refraction, visual acuity (VA), near reading performance and intraocular pressure were monitored for 8 h at a wide range of light levels following bilateral instillation of single drops of 0.1% brimonidine tartate in 19 early presbyopes (40-50 years) and 11 mature presbyopes (>50 years).

RESULTS

Pupil miosis did not alter distance VA or refraction. Significant pupil miosis peaked at 1-2 h after dosing, which expanded the depth of focus of mature presbyopes with the mean improvement in near logMAR VA of -0.15, -0.07 and -0.03, at 20, 200 and 2000 lux, respectively. One hour after instillation, near reading speed improved by 21, 24 and 5 words per min for text size commonly seen in US newspaper and cellphone text messages, 18, 21 and 19 words per min for text size of grocery labels and 12, 13 and 30 words per min for text size of over-the-counter medications at light levels of 20, 200 and 2000 lux, respectively. No such improvements in near VA and near reading speed were observed in the young presbyopes having some residual accommodation. Most of the pupil miosis remained 8 h after instillation, whereas near VA improvements disappeared after 4 h.

CONCLUSION

Low dose miotics can enhance near vision in presbyopic subjects while retaining high quality distance vision over a wide range of light levels. Significant improvements in near vision were observed only during the 1-2 h period after dosing when miosis peaked.

Effect of brimonidine tartrate 0.15% on scotopic pupil size and upper eyelid position: controlled trial

BACKGROUND

To evaluate the effect of brimonidine tartrate 0.15% ophthalmic solution on pupil size under scotopic condition and upper eyelid position.

METHODS

This study comprised 72 eyes of 36 healthy subjects. A single drop of brimonidine tartrate 0.15% ophthalmic solution was instilled in the right eye and artificial tear was instilled in the left eye. Pupil size was measured using an infra-red pupillometer under scotopic condition before and at 30 min, 2, 4, 6, 8 and 10 h after instillation. Measurement of margin reflex distance 1 (MRD1) was performed using a millimetre ruler before and after at 10 min after instillation.

RESULTS

The mean age of the subjects was 32.19 ± 11.43 years (range 10-52 years), 17 were female and 19 were male. Before brimonidine instillation, the mean pupil size was 6.09 ± 1.03 mm in the brimonidine eyes and 6.06 ± 1.04 mm in the control eyes. There was a significant decrease in mean pupil size at 30 min (4.45 ± 1.04), 2 h (4.49 ± 1.06), 4 h (4.59 ± 1.06), 6 h (4.89 ± 1.06) and 8 h (5.38 ± 1.02) after instillation compared to before in brimonidine eyes (p < 0.001 for all). There was a significant miosis continued for at least 6 h (5.95 ± 1.03) in control eyes (p < 0.001). There was no significant change in MRD1, before and after instillation both in brimonidine and control eyes.

CONCLUSIONS

Brimonidine tartrate 0.15% had a significant miosis under scotopic condition for at least 8 h after instillation and had a significant miosis on the untreated eye for at least 6 h.

Correction of presbyopia: old problems with old (and new) solutions

We live in a three-dimensional world and the human eye can focus images from a wide range of distances by adjusting the power of the eye's lens (accommodation). Progressive senescent changes in the lens ultimately lead to a complete loss of this ability by about age 50, which then requires alternative strategies to generate high-quality retinal images for far and close viewing distances. This review paper highlights the biomimetic properties and underlying optical mechanisms of induced anisometropia, small apertures, dynamic lenses, and multi-optic lenses in ameliorating the visual consequences of presbyopia. Specifically, the advantages and consequences of non-liner neural summation leveraged in monovision treatments are reviewed. Additionally, the value of a small pupil is quantified, and the impact of pinhole pupil location and their effects on neural sensitivity are examined. Different strategies of generating multifocal optics are also examined, and specifically the interaction between ocular and contact or intraocular lens aberrations and their effect on resulting image quality are simulated. Interestingly, most of the novel strategies for aiding presbyopic and pseudophakic eyes (for example, monovision, multifocality, pinhole pupils) have emerged naturally via evolution in a range of species.

Effects of brimonidine tartrate 0.1% ophthalmic solution on the pupil, refraction, and light reflex

This study aimed to assess changes in pupil size, uncorrected visual acuity, refraction, and the direct and consensual light reflexes after instillation of brimonidine 0.1% in healthy subjects. The investigation comprised 46 eyes of 23 healthy subjects with no eye diseases in whom brimonidine 0.1% was instilled in the right eye. Pupil size was measured quantitatively under photopic and scotopic conditions, uncorrected visual acuity, refraction, and direct and consensual light reflexes before and at 1, 6, and 24 h after instillation. We found No significant change was found in refraction or uncorrected visual acuity (P = 0.999 and P = 0.998, respectively). A significant reduction in pupil size was observed under scotopic conditions at 1 h and 6 h after instillation (P = 0.007 and P = 0.005, respectively). The rate of pupil contraction and constriction speed measured by light reflexes were significantly increased at 1 h and 6 h after instillation (P = 0.021 and P = 0.033, respectively). Brimonidine 0.1% induced a significant reduction in pupil size under scotopic conditions without a significant change in refraction or visual acuity due to suppression of the sympathetic nervous system.

Brimonidine Ophthalmic Solution 0.025% for Reduction of Ocular Redness: A Randomized Clinical Trial

SIGNIFICANCE

The α2-adrenergic receptor agonist brimonidine has been reported to induce conjunctival blanching in cataract, strabismus, laser refractive, and filtration procedures. Clinicians are often faced with red eyes with no apparent underlying pathology. Low-dose brimonidine reduced ocular redness in such subjects with efficacy maintained over 1 month and negligible rebound redness.

PURPOSE

The aim of this study was to evaluate the safety and efficacy of brimonidine tartrate ophthalmic solution 0.025% for the treatment of ocular redness.

METHODS

In this single-center, double-masked, phase 3 clinical trial, adult subjects with baseline redness of more than 1 unit in both eyes (0- to 4-unit scale) were randomized 2:1 to brimonidine 0.025% or vehicle. A single dose was administered in-office (day 1); thereafter subjects instilled treatment four times a day for 4 weeks, with clinic visits on days 15, 29, and 36 (7 days post-treatment). Efficacy end points included investigator-evaluated redness 5 to 240 minutes post-instillation on day 1 (primary); investigator-evaluated change from baseline 1, 360, and 480 minutes post-instillation on day 1, and 1 and 5 minutes post-instillation on days 15 and 29; total clearance of redness, and subject-assessed redness. Safety/tolerability measures included adverse events, rebound redness, and drop comfort.

RESULTS

Sixty subjects were randomized (n = 40 brimonidine, n = 20 vehicle). Investigator-assessed redness was lower with brimonidine versus vehicle over the 5- to 240-minute post-instillation period (mean [SE], 0.62 [0.076] vs. 1.49 [0.108]; P < .0001) and at each time point within that period (P < .0001). At 1, 360, and 480 minutes post-instillation, respectively, the mean differences (95% confidence interval) between treatments were -0.73 (-1.05 to -0.41), -0.57 (-0.84 to -0.29), and -0.39 (-0.67 to -0.10), respectively. No tachyphylaxis was evident with brimonidine on days 15 and 29, and minimal rebound redness was observed following discontinuation. Adverse events were infrequent, and brimonidine was rated as very comfortable.

CONCLUSIONS

Brimonidine 0.025% appeared safe and effective for reduction of ocular redness, with an 8-hour duration of action, no evidence of tachyphylaxis, and negligible rebound redness.

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

Purpose/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.

Analysis of various factors affecting pupil size in patients with glaucoma

Background

Pupil size is an important factor in predicting post-operative satisfaction. We assessed the correlation between pupil size, measured by Humphrey static perimetry, and various affecting factors in patients with glaucoma.

Methods

In total, 825 eyes of 415 patients were evaluated retrospectively. Pupil size was measured with Humphrey static perimetry. Comparisons of pupil size according to the presence of glaucoma were evaluated, as were correlations between pupil size and various factors, including age, logMAR best corrected visual acuity (BCVA), retinal nerve fiber layer (RNFL) thickness, spherical equivalent, intraocular pressure, axial length, central corneal thickness, white-to-white, and the kappa angle.

Results

Pupil size was significantly smaller in glaucoma patients than in glaucoma suspects (p < 0.001) or the normal group (p < 0.001). Pupil size decreased significantly as age (p < 0.001) and central cornea thickness (p = 0.007) increased, and increased significantly as logMAR BCVA (p = 0.02) became worse and spherical equivalent (p = 0.007) and RNFL thickness (p = 0.042) increased. In patients older than 50 years, pupil size was significantly larger in eyes with a history of cataract surgery.

Conclusions

Humphrey static perimetry can be useful in measuring pupil size. Pupil size was significantly smaller in eyes with glaucoma. Other factors affecting pupil size can be used in a preoperative evaluation when considering cataract surgery or laser refractive surgery.

The effect of Timolol 0.5% on the correction of myopic regression after LASIK

BACKGROUD

Postlaser in situ keratomileusis (post-LASIK) refractive regression is defined as the gradual, partial, or total loss of initial correction that limits the predictability, efficiency, and long-term stability of LASIK. Our study assesses the effect of Timolol 0.5% on the correction of myopic regression after LASIK.

METHODS

This prospective, randomized, controlled study included 62 eyes of 62 patients with myopic regression of -1.18 ± 0.86 diopters (D) after myopic LASIK. They were randomly assigned into either Group 1 who received Timolol 0.5% eye drops for 3 months or Group 2 who received artificial tears as control (during treatment). Patients were followed an additional 2 months after cessation of eye drops treatment (posttreatment).

RESULTS

During treatment in Group 1, as the mean true intraocular pressure (IOPT) lowered significantly, regression stopped. As the mean IOPT increased significantly posttreatment and returned to its pretreatment level, regression recurred. The effective rate of Timolol therapy dropped from 62.5% during treatment to 40.6% posttreatment. On the contrary in Group 2, although the mean IOPT did not change significantly, regression continually happened as time passed. During treatment, the mean IOPT, uncorrected visual acuity, spherical equivalent (SE), and corneal refractive power showed significant difference between the 2 groups. In Group 1, the differences of effective rate of Timolol therapy between each of the 2 subgroups of age, gender, preoperative SE (PSE), or pretreatment time (how long we start treatment with Timolol post-LASIK) were not statistically significant.

CONCLUSION

IOP-lowering eye drop Timolol was effective for the correction of myopic regression when a 0.5-D or greater myopic shift is detected after LASIK in patients regardless of age, gender, PSE, or anytime we started the treatment only if regression happened. However, the myopic regression recurred after cessation of Timolol treatment.

Clinical outcomes of combined versus separate carbachol and brimonidine drops in correcting presbyopia

Background

To test and compare in a masked fashion the efficacy of using a parasympathomimetic drug (3% carbachol) and an alpha-2 agonist (0.2% brimonidine) in both combined and separate forms to create optically beneficial miosis to pharmacologically improve vision in presbyopia.

Methods

A prospective, double-masked, randomized, controlled clinical trial was conducted. Ten naturally emmetropic and presbyopic subjects between 42 and 58 years old with uncorrected distance visual acuity of at least 20/20 in both eyes without additional ocular pathology were eligible for inclusion. All subjects received 3% carbachol and 0.2% brimonidine in both combined and separate forms, 3% carbachol alone and 0.2% brimonidine (control) alone in their non-dominant eye in a crossover manner with one week washout between tests. The subjects’ pupil sizes and both near and distance visual acuities will be evaluated pre- and post-treatment at 1, 2, 4, and 8 h, by a masked examiner at the same room illumination.

Results

Statistically significant improvement in mean near visual acuity (NVA) was achieved in all subjects who received combined 3% carbachol and 0.2% brimonidine in the same formula compared with those who received separate forms or carbachol alone or brimonidine alone (P < 0.0001).

Conclusion

Based on the data, the combined solution demonstrated greater efficacy than the other solutions that were tested. Improving the depth of focus by making the pupil small caused statistically significant improvement in near visual acuity, with no change in binocular distance vision.

Trial registration

ACTRN12616001565437. Registered 11 November 2016.

Quadrant Field Pupillometry Detects Melanopsin Dysfunction in Glaucoma Suspects and Early Glaucoma

It is difficult to detect visual function deficits in patients at risk for glaucoma (glaucoma suspects) and at early disease stages with conventional ophthalmic tests such as perimetry. To this end, we introduce a novel quadrant field measure of the melanopsin retinal ganglion cell mediated pupil light response corresponding with typical glaucomatous arcuate visual field defects. The melanopsin-mediated post-illumination pupil response (PIPR) was measured in 46 patients with different stages of glaucoma including glaucoma suspects and compared to a healthy group of 21 participants with no disease. We demonstrate that the superonasal quadrant PIPR differentiated glaucoma suspects and early glaucoma patients from controls with fair (AUC = 0.74) and excellent (AUC = 0.94) diagnostic accuracy, respectively. The superonasal PIPR provides a linear functional correlate of structural retinal nerve fibre thinning in glaucoma suspects and early glaucoma patients. This first report that quadrant PIPR stimulation detects melanopsin dysfunction in patients with early glaucoma and at pre-perimetric stages may have future implications in treatment decisions of glaucoma suspects.

Pre- and postsynaptic effects of brimonidine on isolated rabbit iris dilator muscles

Purpose

Brimonidine is an imidazoline compound used for the treatment of glaucoma, but having very little effect on pupil diameter. Like para-aminoclonidine, most imidazoline compounds interact with postsynaptic α-adrenoceptors and cause pupil dilatation. Therefore, as part of an investigation of the mechanism of action of brimonidine on pupil diameter, the present study was initiated to measure, in vitro, the relative potency of brimonidine on the pre- and postsynaptic α-adrenoceptors of rabbit iris dilator muscle.

Methods

The contractile activity of brimonidine and its effect on twitch contraction evoked by electrical field stimulation were studied in isolated rabbit iris dilator muscles by isometric tension recording.

Results

Brimonidine significantly inhibited the twitch contraction of the dilator muscle caused by field stimulation, without affecting the response to exogenously applied phenylephrine. Compared to phenylephrine, brimonidine caused only a small contractile response with % maximum contraction values of <10%.

Conclusion

These results suggest that brimonidine may act on nerve endings to inhibit adrenergic neurotransmission with very little effect on postsynaptic α-adrenoceptors. This may indicate that brimonidine reduced the pupil diameter just a little, thus improving night vision.

Studying the effect of iris mechanics on the pupillary light reflex using brimonidine-induced anisocoria

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Pupil dynamics in Chinese subjects with angle closure

OBJECTIVE

To evaluate the speed of pupil constriction (SPC) in response to a standardized change in illumination from dark to light using anterior segment optical coherence tomography (AS-OCT) in eyes with closed angles, compared to those with open angles.

METHODS

This was a prospective, comparative, observational study. Study subjects with primary angle-closure glaucoma (PACG) and/or primary angle-closure (PAC) were recruited along with a group of normal as controls. Videos of iris and anterior segment changes in response to illumination were captured with real-time video recording from AS-OCT and analysed frame by frame, beginning from a dilated to a constricted pupil. Customized software was used to measure speed of iris constriction, anterior chamber depth (ACD), anterior chamber width (ACW), iris thickness, and pupil diameter (PD). SPC was defined as the rate of pupil diameter change in response to illumination.

RESULTS

One hundred and sixty three Chinese subjects were recruited in this study. A total of 137 of 163 eligible videos (82.5%) were available for analysis, comprising 87 subjects with closed angles (all had undergone laser peripheral iridotomies before) and 50 with open angles. SPC was less in eyes with closed angles (1.22 mm/sec vs 1.56 mm/sec, p<0.001), after adjusting for age and ACW, and was positively correlated with axial length, ACD, anterior chamber angle status, PD in the dark, and iris thickness in the dark, (all r>0.2, all p<0.05). In multivariate analysis, SPC was independently associated with anterior chamber angle status (closed angle vs open angle) (β=0.276, p=0.016) and PD in dark (β= 0.129, p=0.009), after adjusting for age, ACW, ACD, iris thickness and vertical cup-to-disc ratio.

CONCLUSIONS

Compared to those with open angles, eyes with closed angles in Chinese subjects have slower speed of pupil constriction in response to dark-light change, even after adjusting for biometric factors associated with angle closure. The results suggest that differences in irido-pupillary dynamics may play a role in the pathogenesis of angle closure.

Effects of brimonidine 0.2%-timolol 0.5% fixed-combination therapy for glaucoma

PURPOSE

To evaluate the effects of brimonidine 0.2%-timolol 0.5% fixed-combination therapy in the treatment of patients with glaucoma.

METHODS

To measure the main treatment effects of a fixed combination of brimonidine 0.2%-timolol 0.5%, we conducted three small studies: (1) a comparison of diurnal intraocular pressure (IOP) at baseline and at 6 months after brimonidine/timolol fixed-combination therapy (n = 81); (2) an assessment of the effects of one drop of the brimonidine/timolol fixed combination on diurnal IOP (n = 25); and (3) the effects of brimonidine/timolol fixed-combination therapy on the anterior ocular segment over time (n = 64).

RESULTS

(1) After 6 months of treatment with the brimonidine/timolol fixed combination, the mean diurnal IOP in primary open-angle glaucoma (POAG) decreased from 21.4 ± 2.0 to 14.5 ± 3.1 mmHg (32.2%, P < 0.001), and the mean diurnal IOP in normal-tension glaucoma (NTG) decreased from 13.5 ± 2.8 to 10.9 ± 2.0 mmHg (19.3%, P < 0.001). (2) After instillation with one drop of the brimonidine/timolol fixed combination, the IOP in the instilled eye was lowest at 9:00 p.m. and had decreased by 1.7 mmHg compared with the baseline IOP in the instilled eye. The difference in IOP between the instilled eye and untreated fellow eye was largest at 3:00 p.m., measuring 1.7 mmHg (P = 0.011). (3) Brimonidine/timolol fixed-combination therapy caused significant miosis over time (P = 0.003).

CONCLUSIONS

The results of this study suggest that brimonidine/timolol fixed-combination therapy has beneficial IOP-lowering effects and significant effects on pupil size.

Bimatoprost 0.03% versus brimonidine 0.2% in the prevention of intraocular pressure spike following neodymium:yttrium–aluminum–garnet laser posterior capsulotomy

PURPOSE

The aim of this study was to compare the efficacy of bimatoprost 0.03% with brimonidine 0.2% in preventing intraocular pressure (IOP) elevations after neodymium:yttrium–aluminum–garnet (Nd:YAG) laser posterior capsulotomy.

METHODS

In this prospective, randomized, double-masked study, 195 eyes of 195 consecutive patients who had YAG laser capsulotomy for posterior capsule opacification were recruited. Eyes received either 1 drop of bimatoprost 0.03% (98 patients) or brimonidine 0.2% (97 patients) at 1h before laser surgery. A masked observer measured IOP by Goldmann applanation tonometry before treatment and after treatment at 1h, 3h, 24h, and 7 days. Inflammation was evaluated after surgery. Formation of cystoid macular edema was assessed by measuring the macular thickness before and after laser surgery.

RESULTS

The average peak of postoperative IOP elevation was 2.2±3.9mm Hg in the bimatoprost 0.03% and 3.6±3.1mm Hg in the brimonidine 0.2% group. The difference was statistically significant (P<0.001). Postoperative IOP elevations of 10mm Hg or more occurred in 1 eye (1.56%) in the bimatoprost 0.03% group and 5 eyes (7.35%) in the brimonidine 0.2%. This difference was statistically significant (P<0.001). Macular edema and anterior chamber reaction were not observed related to bimatoprost. No clinically significant side effects were noted in either group.

CONCLUSIONS

Our results indicate that prophylactic use of bimatoprost 0.03% is more effective than brimonidine 0.2% in preventing IOP elevation immediately after YAG laser capsulotomy. Bimatoprost 0.03% as a prostamide analog may provide new option for preventing IOP elevation after YAG laser capsulotomy.

Effects of some ophthalmic medications on pupil size: a literature review

Ophthalmological pharmacology is a rapidly expanding field aimed at achieving the safest and most effective treatment results. Physicians must be aware of the side-effect profiles, both beneficial and harmful, of medications currently used. This review highlights the available data on the effect of some ophthalmic medications on pupil size; it was limited to all reports or studies describing topical ophthalmic agents not originally designed or indicated to alter pupil diameter. This awareness will protect patients from unwanted drug-induced side effects and will improve clinical management and patient care.

Efficacy of brimonidine tartrate 0.2% ophthalmic solution in reducing halos after laser in situ keratomileusis

PURPOSE

To quantitatively evaluate the effect of brimonidine tartrate 0.2% (Alphagan) on halo and pupil size in patients who had symptomatic night-vision difficulties after laser in situ keratomileusis (LASIK).

SETTING

Nune Eye Hospital, Seoul, Korea.

METHODS

This study comprised 28 eyes of 14 patients with symptomatic night-vision difficulties after LASIK. Pupil diameter was measured with a Colvard pupillometer (Oasis Medical, Inc.). Quantitative analysis of halos was performed by measuring the area using a new computerized method. Pupil size and halo size were evaluated under scotopic and normal room light conditions. Alphagan was administered, and the effect was measured after 30 minutes and 1, 6, 12, and 24 hours.

RESULTS

There was a statistically significant correlation between pupil size and halo size (r = 0.527; P<.0001; slope = 691.6 pixel/mm). Pupil size and halo size decreased significantly 30 minutes after Alphagan instillation under both luminance conditions (all P< .0001). Under normal room light, the pupil and halo remained decreased until the last measurement at 24 hours. Under scotopic conditions, the pupil returned to its preinstillation size at 24 hours while the halo remained decreased. The maximum effect on halos was observed after 6 hours, when the mean reduction over preinstillation size was 28.2% and 29.1% under normal room light conditions and scotopic conditions, respectively.

CONCLUSION

Alphagan effectively reduced halo size and pupil size in postoperative LASIK patients with night-vision symptoms.

Effect of Brimonidine Tartrate 0.15% on Scotopic Pupil: Controlled Trial

PURPOSE

The aim of this study was to evaluate the duration of the effect of one single dose of brimonidine tartrate 0.15% on pupil diameter, under scotopic conditions, when applied topically in 1 eye of normal subjects.

METHODS

The eyes of 19 normal volunteers were randomized so that 1 eye had 1 drop of brimonidine tartrate 0.15% and the other received no medication. Pupil diameter was measured using an infrared pupillometer. The first measure was obtained before the instillation of brimonidine. After that, four measures, with 2-h intervals, were performed.

RESULTS

From 19 participants, 14 were women and 5 were men, with a mean age of 25.05 years (standard deviation, +/- 6.98). Before brimonidine instillation, mean pupil diameter in the control eyes was 5.11 mm, and in the brimonidine eyes it was 5.15 mm. After 8 h, the mean pupil size was 4.01 mm in the treated eyes, and 4.56 mm in the untreated eyes. There was a tendency of miotic effect to be more important on the treated eye, as compared to the control eye in all intervals, but this did not reach statistical significance (P = 0.375). When comparing both eyes, independently of the periods, the treated eye had a smaller diameter than the untreated eye (P = 0.038). The miotic effect was observed for at least 8 h after instillation.

CONCLUSIONS

Miotic response of brimonidine tartrate 0.15% lasted for at least 8 h and has a significant effect on the nontreated eye.

Pupil size and corneal laser surgery

PURPOSE OF REVIEW

The role of scotopic pupil size as a factor in predicting night vision complaints is controversial. This review summarizes reports in the literature, some that have found and some that have failed to find a correlation with scotopic pupil size and night vision complaints.

RECENT FINDINGS

Pupil-measuring devices are discussed along with informed consent issues and reports showing that wavefront aberrations increase with increasing pupil size. A new objective measuring device (Larson) showed a correlation with postoperative starbursts and pupil size and a decrease in starbursts with wavefront-guided treatments compared with conventional excimer laser treatments. Cortical adaptation allows many patients to adapt to their new night vision. Treatment options for those who remain symptomatic include drops to reduce pupil size and wavefront-guided retreatments.

SUMMARY

Reports in the literature are conflicting, and refractive surgeons would be wise to inform their patients that large scotopic pupil size is a potential risk factor for night vision complaints. By doing this they will follow the recommendations in recent patient information brochures of both VISX (Santa Clara, California) and Alcon (Orlando, Florida) and on the United States Food and Drug Administration web site.

[The effect of brimonidine on the pupillary reflex. A pupillographic study in healthy volunteers]

PURPOSE

The effect of brimonidine in comparison with acetazolamide on pupillary reflex was investigated in 18 volunteers.

METHODS

Infrared pupillography was performed with white diode light of 200 ms duration to measure pupil diameter, constriction latency, reaction time, constriction amplitude, and relative constriction amplitude. The measurements were performed according to a fixed schedule including a phase without medication to determine the baseline level. Data were analyzed by Student's paired t-test.

RESULTS

Application of brimonidine and acetazolamide led to a significantly reduced intraocular pressure as well as static and dynamic differences in the pupillary reflex. The pupil diameter measurements were significantly smaller after both medications in comparison to baseline. The reduction of pupil diameter after brimonidine led to significantly reduced contraction amplitude and prolonged latency.

CONCLUSION

Application of brimonidine leads to significant miosis, which might due to the affinity to alpha(2)-receptors with reduction of noradrenaline release in the synapse. This effect may play a role in a higher decrease of intraocular pressure by increasing aqueous humor outflow in comparison to clonidine and apraclonidine, but further investigations are required.

Pharmacological management of night vision disturbances after refractive surgery

PURPOSE

To evaluate the efficacy and safety of diluted aceclidine eyedrops in reducing night vision disturbances after refractive surgery.

SETTING

Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano-Milano, Italy.

METHODS

This double-masked randomized clinical trial included 30 patients (60 eyes) with chronic night vision disturbance after refractive surgery. Patients were randomly allocated to receive (1) placebo, (2) aceclidine 0.016%, or (3) aceclidine 0.032%. Drugs were administered once or twice daily. Anterior segment, haze, uncorrected visual acuity, best corrected visual acuity, intraocular pressure, corneal maps, and scotopic pupil size were determined at baseline and at follow-up examinations (15 and 30 days after inclusion). Halos and double vision 4-step scales were built to determine subjective grading of night vision disturbance, and the root mean square (RMS) was calculated to determine objective changes in night vision disturbance.

RESULTS

The effect of diluted aceclidine started about 15 minutes after instillation and lasted for about 5 hours. No difference between the 2 dilutions could be found. Thirty-nine of 40 treated eyes showed a reduction in night vision disturbance. The mean reduction in halos and double vision grading was 1.42 +/- 0.5 (SD) and 1.14 +/- 0.4, respectively. A mean decrease in pupil size of 2.5 mm was measured. Thirty minutes after the instillation of diluted aceclidine, the topography-derived wavefront error showed a statistically significant reduction in RMS values (total, spherical, astigmatic, coma, and higher order), which was maintained for 5 hours. A transitory conjunctival hyperemia was the only side effect reported.

CONCLUSION

Diluted aceclidine seemed to be an effective and safe treatment for night vision disturbance following refractive surgery.

Evaluation and management of plateau iris syndrome: case report and review

BACKGROUND

This article documents a case of plateau iris syndrome and provides a review of the current concepts regarding the pathogenesis, diagnosis, and management of this condition.

CASE REPORT

A patient who had patent peripheral iridotomies O.D. and O.S. to treat previous episodes of acute angle closure came to clinic with unilaterally elevated intraocular pressures, narrow anterior chamber angles, and a flat iris configuration. The patient was diagnosed with plateau iris syndrome.

CONCLUSIONS

The clinician must be aware of, and be able to distinguish, the clinical signs that are characteristic of plateau iris syndrome. An understanding of the mechanisms involved in the development of this type of primary angle closure may facilitate its appropriate diagnosis and management.

Brimonidine versus dapiprazole: Influence on pupil size at various illumination levels

PURPOSE

To evaluate the influence of dapiprazole versus brimonidine on pupil size at various illumination levels.

SETTING

Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany.

METHODS

In randomized prospective study, 19 healthy volunteers received 2 ophthalmic solutions, dapiprazole and brimonidine, 1 in each eye, for intraindividual comparison. Before and after application, pupil diameter was measured using an infrared binocular pupillometer at 3 illumination levels (0.03, 0.82, and 6.4 lux).

RESULTS

Only slight pupil dilation was observed under scotopic conditions after application of both agents. After 20 minutes, the median reduction in pupil width was 1.4 mm for brimonidine and 0.9 mm for dapiprazole. These effects were statistically significant for both agents (both P < .001). The maximum effect was observed after 40 minutes and remained stable through the next measurement at 180 minutes. Under mesopic lighting conditions, only a slight effect (<1 mm) was seen.

CONCLUSIONS

Pupil mydriasis at scotopic illumination levels was reduced by both drugs in a similar fashion. Because of the slightly stronger effect of brimonidine, application of this agent 20 minutes before activities in dimly lit areas or at night may be recommended for photic phenomena following refractive surgery.

Miotic effect of brimonidine tartrate 0.15% ophthalmic solution in normal eyes

PURPOSE

To evaluate the effect of brimonidine tartrate 0.15% ophthalmic solution (Alphagan P) on pupil diameter in eyes of healthy adults under different luminance conditions.

SETTING

Center for Refractive Surgery, Ophthalmology Service, Department of Surgery, Walter Reed Army Medical Center, Washington, DC, USA.

METHODS

Using a Colvard pupillometer, the pupil diameter was measured in 15 eyes of 15 healthy adults under 3 luminance conditions (scotopic, mesopic, photopic). The luminance of the room was measured using the Minolta LS-110 Luminance Meter. Pupil diameter was remeasured using the same technique 30 minutes, 4 hours, and 6 hours after administration of 1 drop of brimonidine tartrate 0.15% ophthalmic solution.

RESULTS

Under scotopic conditions (luminance 0.0 candelas [cd]/m(2)), the pupil diameter decreased by 1.0 mm or more in 100%, 87%, and 60% of eyes at 30 minutes, 4 hours, and 6 hours, respectively (P<.005); under mesopic conditions (luminance 0.2 cd/m(2)), in 93%, 73%, and 40% of eyes, respectively (P<.005); and under photopic conditions (luminance 150.2 cd/m(2)), in 73%, 87%, and 67% of eyes, respectively (P<.005).

CONCLUSIONS

Brimonidine tartrate 0.15% ophthalmic solution produced a significant miotic effect under all 3 luminance conditions. The reproducible miotic effect under scotopic and mesopic conditions may help postoperative refractive patients who report night-vision difficulties related to a large pupil.

Effect of brimonidine tartrate 0.2% ophthalmic solution on pupil size

PURPOSE

To evaluate the effect of brimonidine tartrate 0.2% ophthalmic solution on pupil size under scotopic and photopic luminance conditions in persons considering laser refractive surgery.

SETTING

Ophthalmic Health Center, Tel Aviv, Israel.

METHODS

The pupil size was measured in 36 eyes of 36 participants under scotopic and photopic conditions using the Colvard pupillometer (Oasis Medical) before and after brimonidine tartrate drops were administered. The pupil size was subsequently measured after 30 minutes and 4 and 6 hours.

RESULTS

No difference was found in pupil size before brimonidine tartrate instillation in eyes with light or dark irides. Before instillation, the mean photopic pupil size was 4.81 mm +/- 0.54 (SD) (range 4.0 to 6.0 mm). At 30 minutes, all pupils became miotic, with a mean size of 3.77 +/- 0.51 mm (range 3.0 to 5.0 mm) (P<.0001). After 6 hours, 27.8% of the pupils had returned to their previous size. Before brimonidine tartrate administration, the mean scotopic pupil size was 6.22 +/- 0.73 mm (range 5.0 to 8.0 mm). There was significant miosis to 4.57 +/- 0.84 mm (range 3.0 to 6.5 mm) (P<.0001) that continued for at least 6 hours. The miotic effect of brimonidine tartrate was stronger in eyes with light irides.

CONCLUSIONS

Brimonidine tartrate caused significant miosis, especially under scotopic conditions, most likely from its alpha-2 adrenergic effect. Under photopic luminance conditions, the miotic effect was pronounced.

Update on laser subepithelial keratectomy (LASEK)

PURPOSE OF REVIEW

This study reviews current concepts in laser subepithelial keratectomy (LASEK), variations in LASEK techniques, the role of pharmacology in LASEK, and optimizing outcomes in LASEK.

RECENT FINDINGS

Recent studies continue to support the use of LASEK over that of LASIK in the correction of refractive error. In addition, the advent of pharmacological/biologic intervention, improved algorithms, and wavefront technology have expanded the armamentarium available to ophthalmologists in the maximization of LASEK outcomes.

SUMMARY

LASEK offers an excellent profile in terms of both final outcome (uncorrected visual acuity) and safety (best corrected visual acuity). Untoward effects of LASEK are readily prevented/treated with a variety of agents. Postoperative pain can be ameliorated using topical and oral analgesia. Infection can be most effectively addressed with the fourth generation of fluoroquinolones. Haze may be treated or prevented using numerous remedies namely autologous serum, steroids, ascorbic acid, mitomycin-c, and NSAIDS. Wavefront combined with LASEK rather than with LASIK may offer the best refractive outcome.

The effect of daily use of brimonidine tartrate on the dark-adapted pupil diameter

PURPOSE

To investigate the effect of daily brimonidine tartrate 0.15% on the dark-adapted pupil diameter.

DESIGN

Observational case series.

METHOD

Ten normal volunteers administered brimonidine to their right eyes once daily. Four to six hours later, infrared pupil photographs were taken after dark adaptation. Measurements were performed at baseline; on treatment days 1, 5, 11, and 18; and on washout days 1 and 2.

RESULTS

One subject had no response. The nine responding subjects showed an average maximum antimydriatic effect of -1.63 mm (range, -0.57 mm--2.30 mm); all subjects experienced tachyphylaxis. Five subjects showed rebound mydriasis (mean maximum rebound +0.87 mm larger than baseline; range 0.50 mm-1.22 mm). The untreated pupil also responded, showing antimydriasis (two subjects), rebound mydriasis (two subjects), or paradoxical direct mydriasis (one subject).

CONCLUSIONS

Once-daily use of brimonidine tartrate to prevent dark-induced pupil dilation can lead to tachyphylaxis and rebound mydriasis.

Pupil size in Jewish theological seminary students

PURPOSE

To investigate the authors' clinical impression that pupil size among myopic Jewish theological seminary students is different from pupil size of similar secular subjects.

METHODS

This cross-sectional study was conducted on 28 male Jewish theological seminary students and 28 secular students or workers who were matched for age and refraction. All participants were consecutively enrolled. Scotopic and photopic pupil size was measured by means of a Colvard pupillometer. Comparisons of various parameters between the groups were performed using the two-sample t-test, Fisher exact test, a paired-sample t-test, a two-way analysis of variance, and Pearson correlation coefficients as appropriate.

RESULTS

The two groups were statistically matched for age, refraction, and visual acuity. The seminary students were undercorrected by an average of 2.35 diopters (D), while the secular subjects were undercorrected by only 0.65 D (p<0.01). The average pupil size was larger in the religious group under both scotopic and photopic luminance. This difference was maintained when the two groups were compared according to iris color under both conditions, reaching a level of statistical significance (p<0.0001). There was a significant difference in photopic pupil size between dark and light irises (p=0.049), but this difference was not maintained under scotopic conditions.

CONCLUSIONS

The average pupil size of young ultraorthodox seminary students was significantly larger than that of matched secular subjects. Whether this is the result of intensive close-up work or of apparently characteristic undercorrection of the myopia is undetermined.

Reduction of Pupil Size and Halos With Minus Lenses After Laser in situ Keratomileusis

PURPOSE

To evaluate the amount of miosis induced by over-minused lenses and to assess subjective reduction of halos following laser in situ keratomileusis (LASIK) with such lenses.

METHODS

Part I: Infrared pupil diameter was assessed in 14 patients who had not had ocular surgery. The accommodative/miotic reflex was stimulated with concave trial lenses in -1.00-D increments up to -4.00 D while viewing the 20/40 acuity line. Part II. Subjective halos around a distant light were assessed in 14 patients following LASIK for myopia, with and without a -1.00-D lens over manifest refraction.

RESULTS

Part I: 100%, 79%, and 64% of patients clearly saw the 20/40 line with a -1.00-D lens, -2.00-D lens, and -3.00/-4.00-D lens, respectively. Mean pupil diameter decreased by 0.2 mm with the -1.00-D lens (P = .02), 0.5 mm with the -2.00-D lens (P = .003), 0.9 mm with the -3.00-D lens (P = .008,), and 1.1 mm with the -4.00-D lens (P = .008). Part II: 11 of 14 patients (79%) noticed a decrease in the size of the halo (30% average reduction) when over-minused by -1.00 D.

CONCLUSIONS

Pupil diameters and halos decreased with a -1.00-D overcorrection in patients following LASIK. Patients with pupil-dependent night halos after LASIK may benefit from mildly over-minused lenses.