Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial

OBJECTIVE

To provide the results of the Early Manifest Glaucoma Trial, which compared the effect of immediately lowering the intraocular pressure (IOP), vs no treatment or later treatment, on the progression of newly detected open-angle glaucoma.

DESIGN

Randomized clinical trial.

PARTICIPANTS

Two hundred fifty-five patients aged 50 to 80 years (median, 68 years) with early glaucoma, visual field defects (median mean deviation, -4 dB), and a median IOP of 20 mm Hg, mainly identified through a population screening. Patients with an IOP greater than 30 mm Hg or advanced visual field loss were ineligible.

INTERVENTIONS

Patients were randomized to either laser trabeculoplasty plus topical betaxolol hydrochloride (n = 129) or no initial treatment (n = 126). Study visits included Humphrey Full Threshold 30-2 visual field tests and tonometry every 3 months, and optic disc photography every 6 months. Decisions regarding treatment were made jointly with the patient when progression occurred and thereafter.

MAIN OUTCOME MEASURES

Glaucoma progression was defined by specific visual field and optic disc outcomes. Criteria for perimetric progression were computer based and defined as the same 3 or more test point locations showing significant deterioration from baseline in glaucoma change probability maps from 3 consecutive tests. Optic disc progression was determined by masked graders using flicker chronoscopy plus side-by-side photogradings.

RESULTS

After a median follow-up period of 6 years (range, 51-102 months), retention was excellent, with only 6 patients lost to follow-up for reasons other than death. On average, treatment reduced the IOP by 5.1 mm Hg or 25%, a reduction maintained throughout follow-up. Progression was less frequent in the treatment group (58/129; 45%) than in controls (78/126; 62%) (P =.007) and occurred significantly later in treated patients. Treatment effects were also evident when stratifying patients by median IOP, mean deviation, and age as well as exfoliation status. Although patients reported few systemic or ocular conditions, increases in clinical nuclear lens opacity gradings were associated with treatment (P =.002).

CONCLUSIONS

The Early Manifest Glaucoma Trial is the first adequately powered randomized trial with an untreated control arm to evaluate the effects of IOP reduction in patients with open-angle glaucoma who have elevated and normal IOP. Its intent-to-treat analysis showed considerable beneficial effects of treatment that significantly delayed progression. Whereas progression varied across patient categories, treatment effects were present in both older and younger patients, high- and normal-tension glaucoma, and eyes with less and greater visual field loss.

Factors for glaucoma progression and the effect of treatment: the early manifest glaucoma trial

OBJECTIVE

To assess factors for progression in the Early Manifest Glaucoma Trial (EMGT), including the effect of EMGT treatment.

SETTING/PARTICIPANTS

Two hundred fifty-five open-angle glaucoma patients randomized to argon laser trabeculoplasty plus topical betaxolol or no immediate treatment (129 treated; 126 controls) and followed up every 3 months.

METHODS

Progression was determined by perimetric and photographic optic disc criteria. Patient-based risk of progression was evaluated using Cox proportional hazard regression models and was expressed as hazard ratios (HR) with 95% confidence intervals (95% CI).

RESULTS

After 6 years, 53% of patients progressed. In multivariate analyses, progression risk was halved by treatment (HR = 0.50; 95% CI, 0.35-0.71). Predictive baseline factors were higher intraocular pressure (IOP) (ie, the higher the baseline IOP, the higher the risk), exfoliation, and having both eyes eligible (each of the latter 2 factors doubled the risk), as well as worse mean deviation and older age. Progression risk decreased by about 10% with each millimeter of mercury of IOP reduction from baseline to the first follow-up visit (HR = 0.90 per millimeter of mercury decrease; 95% CI, 0.86-0.94). The first IOP at that visit (3 months' follow-up) was also related to progression (HR = 1.11 per millimeter of mercury higher; 95% CI, 1.06-1.17), as was the mean IOP at follow-up (HR = 1.13 per millimeter of mercury higher; 95% CI, 1.07-1.19). The percent of patient follow-up visits with disc hemorrhages was also related to progression (HR = 1.02 per percent higher; 95% CI, 1.01-1.03). No other factors were identified.

CONCLUSIONS

Patients treated in the EMGT had half of the progression risk of control patients. The magnitude of initial IOP reduction was a major factor influencing outcome. Progression was also increased with higher baseline IOP, exfoliation, bilateral disease, worse mean deviation, and older age, as well as frequent disc hemorrhages during follow-up. Each higher (or lower) millimeter of mercury of IOP on follow-up was associated with an approximate 10% increased (or decreased) risk of progression.

Predictors of Long-term Progression in the Early Manifest Glaucoma Trial

PURPOSE

To determine progression factors at the end of the Early Manifest Glaucoma Trial (EMGT) based on all EMGT patients and evaluate separately patients with higher and lower baseline intraocular pressure (IOP; median split).

DESIGN

Cohort of clinical trial participants.

PARTICIPANTS

Patients with early open-angle glaucoma randomized to argon laser trabeculoplasty plus betaxolol (n = 129) or no immediate treatment (n = 126), examined every 3 months for up to 11 years.

METHODS

Cox proportional hazard analyses, expressed by hazard ratios (HRs) and 95% confidence intervals (CIs).

MAIN OUTCOME MEASURE

Time to progression, defined by perimetric and photographic disc criteria.

RESULTS

Overall progression was 67% when follow-up ended (median, 8 years). Treatment approximately halved progression risk (HR, 0.53; 95% CI, 0.39-0.72); results were similar for patients with higher and lower baseline IOP (HRs, 0.41 and 0.55). Baseline progression factors (HRs, 1.51-2.12; P<0.01) were higher IOP, exfoliation, bilateral disease, and older age, as previously reported. New baseline predictors were lower ocular systolic perfusion pressure in all patients (< or =160 mmHg; HR, 1.42; 95% CI, 1.04-1.94), cardiovascular disease history (HR, 2.75; 95% CI, 1.44-5.26) in patients with higher baseline IOP, and lower systolic blood pressure (BP) (< or =125 mmHg; HR, 0.46; 95% CI, 0.21-1.02) in patients with lower baseline IOP. Postbaseline progression factors were IOP levels at follow-up, with 12% to 13% average increase per millimeter of mercury in all patients (HRs, 1.12-1.13 per mmHg higher) and similar results in patients with higher and lower baseline IOP (HRs, 1.15 and 1.13 per mmHg higher). Disc hemorrhages (HR, 1.02; 95% CI, 1.01-1.03 per percent higher frequency) also predicted progression. Thinner central corneal thickness (CCT) (HR, 1.25; 95% CI, 1.01-1.55 per 40 microm lower) was a new significant factor, a result observed in patients with higher baseline IOP (HR, 1.42; 95% CI, 1.05-1.92 per 40 microm lower) but not lower baseline IOP, with significant IOP-CCT interaction.

CONCLUSIONS

Treatment and follow-up IOP continued to have a marked influence on progression, regardless of baseline IOP. Other significant factors were age, bilaterality, exfoliation, and disc hemorrhages, as previously determined. Lower systolic perfusion pressure, lower systolic BP, and cardiovascular disease history emerged as new predictors, suggesting a vascular role in glaucoma progression. Another new factor was thinner CCT, with results possibly indicating a preferential CCT effect with higher IOP.

Early Manifest Glaucoma Trial: design and baseline data

OBJECTIVES

The Early Manifest Glaucoma Trial (EMGT) will evaluate the effectiveness of reducing intraocular pressure (IOP) in early, previously untreated open-angle glaucoma. Its secondary aims are to explore factors related to glaucoma progression and to study the natural history of the disease. This article describes the EMGT design and presents baseline data.

DESIGN

Randomized, clinical trial.

PARTICIPANTS

Newly diagnosed patients 50 to 80 years of age with early glaucomatous visual field defects were mainly identified from a population-based screening of more than 44,000 residents of Malmö and Helsingborg, Sweden. Exclusion criteria were advanced visual field loss; mean IOP greater than 30 mmHg or any IOP greater than 35 mmHg; visual acuity less than 0.5; and inability to complete follow-up protocols.

INTERVENTIONS

After informed consent, patients were randomized to treatment or no initial treatment with close follow-up. Treated patients had laser trabeculoplasty and started receiving topical betaxolol twice daily in eligible eyes. Follow-up visits include computerized perimetry and tonometry every 3 months and fundus photography every 6 months. Decisions to change or begin treatment are made jointly with the patient when EMGT progression occurs and also later if clinically needed.

MAIN OUTCOME MEASURES

The EMGT progression is defined by sustained increases of visual field loss in three consecutive C30-2 Humphrey tests, as determined from computer-based analyses, or by optic disc changes, as determined from flicker chronoscopy and side-by-side comparisons of fundus photographs performed by masked, independent graders.

RESULTS

A total of 255 patients were randomized between 1993 and 1997 and will be followed for at least 4 years. All had generally good health status; mean age was 68.1 years, and 66% were women. At baseline, mean IOP was 20.6 mmHg and 80% of eyes had IOP less than 25 mmHg.

CONCLUSIONS

The Early Manifest Glaucoma Trial is the first large randomized, clinical trial to evaluate the role of immediate pressure reduction, as compared to no initial reduction, in patients with early glaucoma and normal or moderately elevated IOP. Its results will have implications for: (1) the clinical management of glaucoma; (2) understanding the role of IOP and the natural history of glaucoma; and (3) evaluating the rationale for glaucoma screening.

Fluctuation of intraocular pressure and glaucoma progression in the early manifest glaucoma trial

PURPOSE

To investigate whether increased fluctuation of intraocular pressure (IOP) is an independent factor for glaucoma progression.

DESIGN

A cohort of patients was followed up in a randomized clinical trial.

PARTICIPANTS

Two hundred fifty-five glaucoma patients from the Early Manifest Glaucoma Trial (EMGT; 129 treated and 126 control patients).

METHODS

Study visits, conducted every 3 months, included ophthalmologic examinations, IOP measurements, and standard automated perimetry, with fundus photography every 6 months. Intraocular pressure values were included only until the time of progression in those eyes that showed such progression. Individual mean follow-up IOP and IOP fluctuation, calculated as the standard deviation of IOP at applicable visits, were the variables of main interest. Cox regression with time-dependent variables was used to evaluate the association between IOP fluctuation and time to progression, both with and without IOP mean in the models. These analyses also controlled for other significant variables.

MAIN OUTCOME MEASURES

Glaucoma progression, as defined by a predetermined visual field criterion, worsening of the disk, assessed by an independent disc reading center, or both.

RESULTS

Median follow-up time was 8 years (range, 0.1-11.1 years). Sixty-eight percent of the patients progressed. When considering mean follow-up IOP and IOP fluctuation in the same time-dependent model, mean IOP was a significant risk factor for progression. The hazard ratio (HR) was 1.11 (95% confidence interval [CI], 1.06-1.17; P<0.0001). Intraocular pressure fluctuation was not related to progression, with an HR of 1.00 (95% CI, 0.81-1.24; P = 0.999).

CONCLUSIONS

These results confirm our earlier finding that elevated IOP is a strong factor for glaucoma progression, with the HR increasing by 11% for every 1 mmHg of higher IOP. Intraocular pressure fluctuation was not an independent factor in our analyses, a finding that conflicts with some earlier reports. One explanation for the discrepancy is that our analyses did not include postprogression IOP values, which would be biased toward larger fluctuations because of more intensive treatment. In contrast, in this EMGT report, no changes in patient management occurred during the period analyzed.

Measuring visual field progression in the Early Manifest Glaucoma Trial

AIMS

The Early Manifest Glaucoma Trial (EMGT) (316 eligible eyes) has used a new set of criteria to define visual field progression in glaucoma. This paper provides estimates of the amount of visual field worsening required to reach the EMGT definition of definite perimetric progression.

METHODS

In the 148 eyes that reached definite progression, we first determined changes between baseline and the time of definite EMGT progression, both for mean deviation (MD) and for number of highly (p < 0.5%) significantly depressed test points in pattern deviation probability maps. Second, we studied whether such changes depended on baseline MD, intraocular pressure (IOP), age and time to progression, all of which are factors that affect the rate of field progression.

RESULTS

In eyes reaching progression, the mean change in MD from baseline was -1.93 dB (SE +/- 0.20) and the mean change in number of significant points was +4.85 (SE +/- 0.35). These changes did not show linear dependency on baseline MD, IOP or time to progression.

CONCLUSIONS

The average amount of field deterioration needed to reach EMGT visual field progression has been measured and expressed in more conventional units (i.e. a loss of about - 2dB in MD and an increase in about five highly significant points). These estimates will facilitate the clinical interpretation of the results of EMGT.

Factors for progression and glaucoma treatment: The Early Manifest Glaucoma Trial

PURPOSE OF REVIEW

This review summarizes factors for progression in the Early Manifest Glaucoma Trial (EMGT), including the effect of treatment. EMGT randomized patients with early glaucoma either to argon laser trabeculoplasty plus betaxolol (n = 129) or to no immediate treatment (n = 126) and followed them every 3 months.

RECENT FINDINGS

Treated patients had delayed progression, as compared with controls. In Cox regression, EMGT treatment halved the risk of progression (hazard ratio = 0.50; 95% confidence interval: 0.35, 0.71). Risk decreased about 10% with each millimeter mercury of intraocular pressure (IOP) reduction from baseline; the higher (or lower) the IOP at follow-up, the higher (or lower) the risk. Baseline factors increasing progression were higher IOP, exfoliation, bilateral disease, worse perimetric mean deviation and older age; frequent disc hemorrhages at follow-up also increased risk.

SUMMARY

EMGT treatment reduced progression risk in half, demonstrating the value of IOP lowering in early glaucoma. Age and indicators of disease severity also predicted progression.

A double-masked, randomized 1-year study comparing dorzolamide (Trusopt), timolol, and betaxolol. International Dorzolamide Study Group

OBJECTIVE

To investigate the safety profile and efficacy of 2.0% dorzolamide hydrochloride, when administered three times daily for up to 1 year, compared with that of 0.5% timolol maleate and 0.5% betaxolol hydrochloride, each administered twice daily. In addition, the effect of adding dorzolamide to the regimen of patients with inadequate ocular hypotensive efficacy while they were receiving one of the two beta-adrenoceptor antagonists and the effect of adding timolol to the regimen of patients receiving dorzolamide were also evaluated.

DESIGN

A double-masked, randomized, parallel comparison.

SETTING

Multinational study at 34 international sites.

PATIENTS

Five hundred twenty-three patients with open-angle glaucoma or ocular hypertension, 17 to 85 years of age. Patients currently using ocular hypotensive medications were required to undergo a washout.

INTERVENTION

Two percent dorzolamide three times a day, 0.5% timolol (Timoptic, Merck, Whitehouse Station, NJ) twice daily, and 0.5% betaxolol solution (Betoptic, Alcon, Fort Worth, Tex) twice daily.

RESULTS

At 1 year, the mean percent reduction in intraocular pressure at peak of 2% dorzolamide, 0.5% timolol, and 0.5% betaxolol was approximately 23%, 25%, and 21%, respectively. At afternoon trough, the mean percent reduction in intraocular pressure was 17%, 20%, and 15% for dorzolamide, timolol, and betaxolol, respectively.

CONCLUSIONS

The ocular hypotensive efficacy of 2.0% dorzolamide, given three times a day, is comparable with that of 0.5% betaxolol, given twice daily, for up to 1 year. In addition, long-term use of dorzolamide was not associated with clinically meaningful electrolyte disturbances or systemic side effects commonly observed with the use of oral carbonic anhydrase inhibitors.

Treatment and vision-related quality of life in the early manifest glaucoma trial

PURPOSE

To evaluate the effect of treatment, visual function, and other factors on vision-targeted health-related quality of life (HRQOL) of patients with early glaucoma.

DESIGN

Randomized clinical trial.

PARTICIPANTS

Two hundred fifty-five patients with newly detected open-angle glaucoma and repeatable early visual field (VF) defects, 50 to 80 years old (66% female).

METHODS

Patients were randomized to receive either betaxolol plus laser trabeculoplasty in eligible eye(s) or no initial treatment and had ophthalmologic examinations every 3 months. A Swedish translation of the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) was self-administered at 2 follow-up visits (3 and 6 years after randomization).

MAIN OUTCOME

Multiple linear regression analyses determined the effect of treatment and other factors on (1) VFQ-25 composite scores at the first administration and (2) change in scores between administrations.

RESULTS

Two hundred thirty-three patients had 1 NEI VFQ-25 administration and 167 patients had 2 administrations. Internal consistency reliability was high for the composite VFQ-25 score (Cronbach alpha = 0.88) and satisfactory (alpha> or =0.76) for most subscale scores. At the first administration, the composite score was high (88.8+/-11.7). Mean subscale scores were also generally high (98.0-58.3) and were similar for each study group when analyzed separately. Most lower subscale scores were modestly but significantly related to worse visual acuity (VA) or mean deviation (MD) (better eye, r = 0.15-0.35). Composite scores were similar for treated and untreated patients. Lower composite scores were associated with low VA in the better eye (worse than 0.70) and worse perimetric MD (<4.16 decibels) and nuclear lens opacities (Lens Opacities Classification System II grade > or = 2), but not with age, gender, VF progression, intraocular pressure, cardiovascular disease, or hypertension. Between VFQ-25 administrations, larger decreases in the composite score were associated with larger decreases in VA (P<0.05), female gender (P = 0.001), and older age at first administration (P = 0.006). Treatment (assigned at randomization or later in the study) was not associated with change in HRQOL.

CONCLUSIONS

Results suggest that absence or delay of treatment did not influence vision-targeted HRQOL in these newly diagnosed glaucoma patients. However, visual function affected vision-targeted quality of life up to 6 years after Early Manifest Glaucoma Trial enrollment.

Beta-blocker eyedrops and nocturnal arterial hypotension

PURPOSE

To investigate the effects of topical beta-blocker eyedrops on nocturnal arterial hypotension and heart rate and on visual field deterioration.

METHODS

We prospectively investigated 275 white patients, 161 with glaucomatous optic neuropathy and 114 with nonarteritic anterior ischemic optic neuropathy, by 24-hour ambulatory blood pressure monitoring and diurnal curve of intraocular pressure, in addition to detailed ophthalmic evaluation. Of the patients with glaucomatous optic neuropathy, 131 had normal-tension glaucoma and 30 had primary open-angle glaucoma. Of the 275 patients, 114 were using topical beta-blocker eyedrops twice daily (76 with normal-tension glaucoma, 26 with primary open-angle glaucoma, and 12 with anterior ischemic optic neuropathy).

RESULTS

Hourly average blood pressure data analyses showed overall a drop in blood pressure as well as heart rate during sleep, and a significantly greater drop in mean diastolic blood pressure (P = .009) at night in normal-tension glaucoma than in anterior ischemic optic neuropathy. Also, patients using beta-blocker eyedrops experienced a significantly greater percentage drop in diastolic blood pressure at night (P = .028), lower minimum nighttime diastolic blood pressure (P = .072), and lower minimum nighttime heart rate (P = .002) than did those not using them. In normal-tension glaucoma, eyes receiving beta-blocker eyedrops showed visual field progression significantly (P = .0003) more often than those not receiving beta-blockers.

CONCLUSIONS

The findings of our studies, as well as those of others, suggest that any factor that increases nocturnal arterial hypotension is a potential risk factor in vulnerable individuals with glaucomatous optic neuropathy or anterior ischemic optic neuropathy. The present study suggests that the use of beta-blocker eyedrops, by aggravating nocturnal arterial hypotension and reducing the heart rate, may be a potential risk factor in susceptible individuals.

Ocular ??-Blockers in Glaucoma Management

Topical beta-blockers reduce the intraocular pressure (IOP) by blockade of sympathetic nerve endings in the ciliary epithelium causing a fall in aqueous humour production. Two types of topical beta-blockers are available for use in glaucoma: nonselective, which block both beta 1- and beta 2-adrenoceptors; and cardioselective, which block only beta 1-receptors. Of the beta-Blockers commercially available, timolol, levobunolol, metipranolol and carteolol are nonselective, and betaxolol is cardioselective. Twice-daily timolol is probably the most effective agent in lowering IOP, although levobunolol is equally effective and can be used once daily with little difference in effect. Carteolol is used twice daily and any theoretical advantage in diminished side effects conferred by its partial beta-agonist activity compared with timolol has not been fully substantiated. Metipranolol is effective twice daily and does not have partial beta-agonist activity. Betaxolol has an effect comparable to timolol in lowering IOP, but is less effective in some patients. beta-Blockers can be used with other antiglaucoma medications, but their combined action with epinephrine (adrenaline) is suspect, particularly in the case of the nonselective beta-blockers, and the effect should be assessed in patients on an individual basis. Local stinging can be a problem in some patients with betaxolol. The most serious side effects of beta-blockers are the exacerbation of chronic obstructive airways disease with nonselective agents and the precipitation of bronchospasm in some patients. Betaxolol seems relatively free of adverse respiratory effects, although this may be dose-related and extreme caution should still be exercised in patients with any history of respiratory illness. Because of the lower risk of precipitating side effects, betaxolol is probably the beta-blocker of first choice for use in glaucoma; timolol or levobunolol are reserved for patients who do not respond satisfactorily to betaxolol and are quite free of respiratory disease.

Topically applied betaxolol attenuates NMDA-induced toxicity to ganglion cells and the effects of ischaemia to the retina

The present results show that topically applied Betoptic(R)(0.5% betaxolol) to the rabbit or rat eye reaches the retina and can counteract the detrimental effects caused by ischaemia/reperfusion or N -methyl- d -aspartate (NMDA)-induced insults to the retina. Betaxolol is a beta(1)-adrenergic blocker but its neuroprotective action is generally thought to be due to its calcium channel blocking properties. Support for this view comes from studies on cultures of cortical neurones where it was found that betaxolol attenuated the NMDA-induced influx of(45)Ca(2+)while beta-adrenoreceptor agonists were ineffective. Topically applied Betoptic(R)to the rabbit eye was observed to reach the retina in maximal amounts within 60 min. Some of the substance was also found in the contralateral retina of the untreated eye suggesting that the agent reaches the retina by local systemic and retinal circulation. Concurrent treatment with Latanoprost(R)did not result in a greater amount of betaxolol reaching the retina. An ophthalmodynamometric procedure, which raises the intraocular pressure, was used to apply an ischaemic insult to the rabbit retina. After three days of reperfusion the b-wave of the electroretinogram was reduced by an average of 59% and the choline acetyltransferase immunoreactivity in the retina was almost obliterated. However, when experiments were carried out on animals which had been treated with one drop of Betoptic(R) twice daily for 4 weeks before ischaemia and also during the reperfusion phase, the reductions in both the b-wave of the electroretinogram and retinal choline acetyltransferase immunoreactivity due to ischaemia/reperfusion were greatly attenuated. Intravitreal injection of NMDA into the rat eye caused a decrease in the immunostaining for Thy-1 antigen which is associated with ganglion cells. The Thy-1 mRNA level was also reduced as was the mRNA for the common subunit of the NMDA receptor, the NR1 subunit. However, in animals subjected to a topical Betoptic(R)regime, before and after intravitreal injection of NMDA, the decreases in the mRNA levels of Thy-1 and NR1 were significantly attenuated.

Effects of glaucoma medications on the cardiorespiratory and intraocular pressure status of newly diagnosed glaucoma patients

AIMS

To evaluate the short term cardiovascular, respiratory, and intraocular pressure (IOP) effects of four glaucoma medications in newly diagnosed glaucoma patients.

METHODS

141 newly diagnosed glaucoma patients were recruited and underwent a full ocular, cardiovascular, and respiratory examination, including an electrocardiogram (ECG) and spirometry. They were prescribed one of four topical glaucoma medications and reviewed 3 months later. One eye of each patient was randomly chosen for analysis, performed using analysis of variance and the chi(2) test.

RESULTS

Latanoprost had the greatest mean IOP lowering effect in both the primary open angle glaucoma (POAG) (p = 0.005) and the "presumed" normal tension glaucoma (NTG) groups (p = 0.33), reducing the IOP by 8.9 mm Hg and 4.1 mm Hg respectively. Timolol was associated with lowered pulse rates and reductions in the spirometry measurements. 41% of patients using brimonidine complained of systemic side effects and over 55% of patients using betaxolol complained of ocular irritation. 28% of patients required an alteration in their glaucoma management.

CONCLUSIONS

Latanoprost appears to be a useful primary treatment for glaucoma patients, in view of superior IOP control and a low incidence of local and systemic side effects. Timolol causes a reduction in measurements of respiratory function, a concern in view of the potential subclinical reversible airways disease in the elderly glaucoma population. Brimonidine is associated with substantial, unpredictable systemic side effects and betaxolol causes ocular irritation and weak IOP control. Spirometry is advised in all patients receiving topical beta blocker therapy to control their glaucoma.

Topically applied betaxolol attenuates ischaemia-induced effects to the rat retina and stimulates BDNF mRNA

It has previously been reported that the beta(1)-adrenoceptor antagonist, betaxolol, can protect retinal neurones from ischaemia when applied topically. It has further been shown that betaxolol can reduce influx of both sodium or calcium into neurones through interaction at neurotoxin site 2 of the sodium channel and the L-type calcium channel, respectively. The present study sought to further investigate the neuroprotective mode of action of betaxolol in the rat retina. Rats were treated topically with L-betaxolol for 10, 5 and 1 min before ischaemia, induced by raising the intraocular pressure above systolic blood pressure for 45 min. This was followed by reperfusion of 3 or 5 days where L-betaxolol was applied topically twice daily. Ischaemia plus reperfusion caused both a loss of immunoreactivity for choline acetyl transferase (ChAT) and a marked reduction of the b-wave of the electroretinogram (ERG). Treatment, as described, with topical L-betaxolol, completely blunted the effects upon ChAT immunoreactivity and caused a significant reversal of the ERG changes. Furthermore, other rats treated topically with commercially available racemic betaxolol (Betoptic Solution, 0.5%) for 6 hr had raised levels of mRNA for brain derived neurotrophic factor (BDNF) but not for basic fibroblast growth factor (bFGF) in their retinas. The combined data provide further evidence that betaxolol can blunt the effects of ischaemia to the rat retina when applied topically just before the insult. Furthermore, the finding that retinal levels of BDNF mRNA are raised following topical betaxolol treatment shows that not only can this drug reach the retina but that it can also induce changes in expression of factors which are known, themselves, to provide neuroprotection to retinal neurones.

Influence of betaxolol and timolol on the visual fields of patients with glaucoma

In a double-masked study, 40 patients with primary open-angle glaucoma were randomly assigned to treatment with betaxolol 0.5% or timolol 0.5% in both eyes twice daily. Visual fields and intraocular pressures were studied. Perimetry was performed with the Octopus G1 program two weeks after a washout period and three, six, 12, and 18 months after initiation of treatment. Both drugs reduced intraocular pressure. The reduction in intraocular pressure in the timolol-treated group was more pronounced than that in the betaxolol-treated group; the difference, however, was not statistically significant. In both treatment groups, the visual fields tended to improve during the first six months of treatment and remained stable or tended to deteriorate thereafter. The treatment effect on the visual field was better in the betaxolol-treated group than it was in the timolol-treated group (P = .041).

A double-masked randomized comparison of the efficacy and safety of unoprostone with timolol and betaxolol in patients with primary open-angle glaucoma including pseudoexfoliation glaucoma or ocular hypertension. 6 month data

PURPOSE

A long-term comparison of the ocular hypotensive efficacy and safety of unoprostone isopropyl 0.15% twice daily with that of timolol maleate 0.5% twice daily and betaxolol HCl 0.5% twice daily.

DESIGN

This was a randomized, multicenter, double-masked, active-controlled 24-month clinical trial involving 27 centers in Europe and Israel.

METHODS

The study population was composed of patients with primary open-angle glaucoma (including pseudoexfoliation) or ocular hypertension. After washout of antiglaucoma medications, intraocular pressure (IOP) was measured at 0, + 2, + 8, and + 12 hours. Patients were randomized in a 2:1:1 ratio to unoprostone, timolol, or betaxolol. Patients returned for examinations at 2 and 6 weeks and 3 and 6 months.

RESULTS

556 patients were randomized. Each drug produced a clinically and statistically (P <.001) significant reduction from baseline in 12-hour diurnal IOP at month 6 (- 4.3 mm Hg, unoprostone; - 5.8 mm Hg, timolol; - 4.9 mm Hg, betaxolol). Differences in adjusted treatment means between unoprostone and timolol and unoprostone and betaxolol were 1.57 mm Hg (95% CI: 1.00, 2.13) and 0.53 mm Hg (95% CI: - 0.03, 1.09), respectively. Unoprostone was clinically equivalent to betaxolol but did not have as great an IOP-lowering effect as timolol. Discontinued for inadequate control of IOP were 7%, 1%, and 4% of the patients for unoprostone, timolol, and betaxolol, respectively. There were no changes of note in visual acuity, pupil size, cup-to-disk ratio, visual fields, or iris color. Changes in heart rate and blood pressure were small, with no clinically significant differences between groups.

CONCLUSIONS

Unoprostone provided a clinically significant IOP-lowering effect equivalent to betaxolol but not to timolol. The side effect profile of unoprostone appears to be comparable to other established IOP-lowering agents.

A comparative study of betaxolol and dorzolamide effect on ocular circulation in normal-tension glaucoma patients

OBJECTIVE

To determine whether dosages of a selective beta-blocking agent (betaxolol) and a topical carbonic anhydrase inhibitor (dorzolamide), sufficient to significantly lower intraocular pressure (IOP), have similar or disparate impact on the retinal and retrobulbar circulation.

DESIGN

Counterbalanced crossover, with open-label use of medications.

PARTICIPANTS

Nine persons with normal-tension glaucoma (NTG).

INTERVENTION

After a 3-week drug washout, NTG patients were studied after 1 month of treatment with either dorzolamide or betaxolol, with determinations of IOP and retinal and retrobulbar hemodynamics.

MAIN OUTCOME MEASURES

At baseline and after treatment with each drug, retinal arteriovenous passage time was determined by scanning laser ophthalmoscopy after fluorescein dye injection, and flow velocities in the central retinal and ophthalmic arteries were measured with color Doppler ultrasonography imaging.

RESULTS

Betaxolol and dorzolamide each lowered IOP significantly, with these changes apparent and maximal after 2 weeks (each P < 0.05). In contrast, dorzolamide (but not betaxolol) accelerated arteriovenous passage of fluorescein dye in the inferior temporal quadrant of the retina (P < 0.05). Neither drug affected arteriovenous passage in the superotemporal retina or any aspect of central retinal or ophthalmic artery flow velocity after either 2 or 4 weeks.

CONCLUSIONS

Although both dorzolamide and betaxolol are effective ocular hypotensive agents and their topical instillation leaves retrobulbar hemodynamics unaltered, dorzolamide alone accelerates inferotemporal retinal dye transit.

Topical ophthalmic beta-adrenergic blockade for the treatment of glaucoma and ocular hypertension

Since the late 1970s, topical beta-adrenergic blockers have been the drugs of choice in treating ocular hypertension and associated glaucoma. The currently available drugs are timolol, betaxolol, levobunolol, metipranolol, and carteolol. All reduce intraocular pressure by decreasing the production of aqueous humor. Although these drugs are applied locally in the eye, they may enter the general circulation and reach concentrations high enough to cause systemic effects, including alterations in heart rate and rhythm, bronchoconstriction, dyslipidemia, and central nervous system abnormalities. Interactions with other drugs may also occur. Ocular beta- blockers differ in beta 1-selectivity (betaxolol is beta 1-selective, whereas the other drugs are nonselective) and in intrinsic sympathomimetic activity (ISA) or partial agonist properties (only carteolol possesses ISA). These differences give betaxolol and carteolol potential advantages in minimizing certain side effects. The advantage of betaxolol vis-à-vis systemic side effects is more clearly established than that of carteolol. Further systematic study is needed to determine what advantages, if any, are conferred by the presence of ISA.

Betaxolol, a selective beta(1)-adrenergic receptor antagonist, diminishes anxiety-like behavior during early withdrawal from chronic cocaine administration in rats

BACKGROUND

Anxiety has been indicated as one of the main symptoms of the cocaine withdrawal syndrome in human addicts and severe anxiety during withdrawal may potentially contribute to relapse. As alterations in noradrenergic transmission in limbic areas underlie withdrawal symptomatology for many drugs of abuse, the present study sought to determine the effect of cocaine withdrawal on beta-adrenergic receptor (beta(1) and beta(2)) expression in the amygdala.

METHODS

Male Sprague Dawley rats were administered intraperitoneal (i.p.) injections of cocaine (20 mg/kg) once daily for 14 days. Two days following the last cocaine injection, amygdala brain regions were micro-dissected and processed for Western blot analysis. Results showed that beta(1)-adrenergic receptor, but not beta(2)-adrenergic receptor expression was significantly increased in amygdala extracts of cocaine-withdrawn animals as compared to controls. This finding motivated further studies aimed at determining whether treatment with betaxolol, a highly selective beta(1)-adrenergic receptor antagonist, could ameliorate cocaine withdrawal-induced anxiety. In these studies, betaxolol (5 mg/kg via i.p. injection) was administered at 24 and then 44 h following the final chronic cocaine administration. Anxiety-like behavior was evaluated using the elevated plus maze test approximately 2 h following the last betaxolol injection. Following behavioral testing, betaxolol effects on beta(1)-adrenergic receptor protein expression were examined by Western blotting in amygdala extracts from rats undergoing cocaine withdrawal.

RESULTS

Animals treated with betaxolol during cocaine withdrawal exhibited a significant attenuation of anxiety-like behavior characterized by increased time spent in the open arms and increased entries into the open arms compared to animals treated with only saline during cocaine withdrawal. In contrast, betaxolol did not produce anxiolytic-like effects in control animals treated chronically with saline. Furthermore, treatment with betaxolol during early cocaine withdrawal significantly decreased beta(1)-adrenergic receptor protein expression in the amygdala to levels comparable to those of control animals.

CONCLUSIONS

The present findings suggest that the anxiolytic-like effect of betaxolol on cocaine-induced anxiety may be related to its effect on amygdalar beta(1)-adrenergic receptors that are up-regulated during early phases of drug withdrawal. These data support the efficacy of betaxolol as a potential effective pharmacotherapy in treating cocaine withdrawal-induced anxiety during early phases of abstinence.

Reactivation of herpes simplex virus keratitis after initiating bimatoprost treatment for glaucoma

PURPOSE

To report a case of herpes simplex virus reactivation after starting bimatoprost treatment for glaucoma.

DESIGN

Interventional case report.

METHODS

A 66-year-old woman had a herpes simplex keratouveitis reactivation that occurred within 1 month after starting bimatoprost. The herpes simplex had been inactive for more than 10 years.

RESULTS

Bimatoprost and prednisolone acetate 0.12% were discontinued; oral acyclovir, ofloxacin, and betaxolol 0.25% were initiated. Two weeks later, prednisolone acetate 1% was added. The reactivation resolved, and 1 month later, the best corrected visual acuity improved to 20/40.

CONCLUSION

Caution should be used in prescribing bimatoprost for patients with a history of herpes simplex virus keratitis.

Longterm visual field follow-up of glaucoma patients treated with beta-blockers

In a prospective, randomized, double-masked study, 44 patients with primary open-angle glaucoma were treated either with 0.5% betaxolol or 0.5% timolol in both eyes twice daily. Twenty-nine patients could be followed up for 48 months. Seventeen of these patients were treated with betaxolol and 12 with timolol. Each examination included visual field measurements with an Octopus automated perimeter 201 (Program G1), intraocular pressure measurement, funduscopy, as well as pulse and arterial blood pressure measurements. Both drugs lowered in the intraocular pressure. This reduction was slightly but not statistically significantly higher in the timolol-treated group. However, the visual fields improved more in the betaxolol group. Patients treated with betaxolol had significantly smaller averaged mean defects (p < 0.05) and higher averaged mean sensitivities (p < 0.05, Wilcoxon rank score text) than did timolol-treated patients at months 3, 6, 12, and 18. Thereafter, the difference between the two groups was not statistically significant in this relatively small sample size. For betaxolol patients the cumulative area-under-the-curve analysis for the worse eye yielded significantly larger mean sensitivities beyond month 12 (exception: month 30; p < 0.05) and significantly smaller mean defects beyond month 6 (p < 0.05).

Clinical trials update from the European Society of Cardiology Heart Failure meeting: SHAPE, BRING-UP 2 VAS, COLA II, FOSIDIAL, BETACAR, CASINO and meta-analysis of cardiac resynchronisation therapy

This article continues a series of reports on recent research developments in the field of heart failure. Key presentations made at the European Society of Cardiology Heart Failure Update meeting, held in Wroclaw, Poland, in June 2004 are reported. The SHAPE study identified a need to educate general practitioners (GPs) in order to optimise treatment of heart failure in primary care. BRING-UP 2 VAS showed that cognitive impairment is very common in elderly heart failure patients and that these patients require specialist care. Carvedilol was shown to be well tolerated and effective in elderly heart failure patients in the observational COLA II study. In the FOSIDIAL study of patients with end-stage renal disease, fosinopril showed no benefit over placebo in reducing the incidence of cardiovascular events in these high-risk patients. The BETACAR study showed that carvedilol and metoprolol produced a similar effect on left ventricular ejection fraction (+13.1% and +12.0%, respectively). Revised mortality data for the CASINO study and a meta-analysis of the effects of cardiac resynchronisation therapy on mortality in the light of the recently published COMPANION study are reported.

Longterm effect of topical beta-blockers on intraocular pressure and visual field sensitivity in ocular hypertension and chronic open-angle glaucoma

In a prospective, randomized study, nineteen patients with ocular hypertension (n = 14) or chronic open-angle glaucoma (n = 5) were treated with either betaxolol 0.5% or timolol 0.5% in both eyes twice daily. Visual field sensitivity and intraocular pressure were assessed with the Octopus perimeter (program G1) and applanation tonometry, respectively, at 3, 6, 12, 24, 36, and 48 months during treatment. Four of the nineteen patients (two timolol-treated and two betaxolol-treated) were lost to follow-up after the 36-month examination. Whereas both drugs reduced the intraocular pressure, the decrease in the timolol-treated group was statistically more pronounced than in the betaxolol-treated group at month 3, 6, and 48 (p < 0.03). In both treatment groups, the visual field mean sensitivity (MS) index decreased slightly during the first six months of treatment, but remained so only in the timolol-treated group at all subsequent examinations. In the betaxolol-treated group, there was a statistically significant increase in MS at the 12, 24, 36, and 48 month visits (p < 0.01). These findings suggest that factors other than IOP alone may determine visual field outcome.

Effectiveness of levobetaxolol and timolol at blunting retinal ischaemia is related to their calcium and sodium blocking activities: relevance to glaucoma

Glaucoma is a chronic optic neuropathy in which retinal ganglion cells die over a number of years. The initiation of the disease and its progression may involve an ischaemic-like insult to the ganglion cell axons caused by an alteration in the quality of blood flow. Thus, to effectively treat glaucoma it may be necessary to counteract the ischaemic-like insult to the region of the optic nerve head. Studies on the isolated optic nerve suggest that substances that reduce the influx of sodium would be particularly effective neuroprotectants. Significantly, of the presently used antiglaucoma substances, only beta-blockers can reduce sodium influx into cells. Moreover, they also reduce the influx of calcium and this would be expected to benefit the survival of insulted neurones. Betaxolol is the most effective antiglaucoma drug at reducing sodium/calcium influx. Our electroretinographic data indicated that topical application of levobetaxolol to rats attenuated the effects of ischaemia/reperfusion injury. Timolol was also effective but to a lesser extent. Based on these data we conclude that beta-blockers may be able to blunt ganglion cell death in glaucoma, and that levobetaxolol may be a more effective neuroprotectant than timolol because of its greater capacity to block sodium and calcium influx.