A 7 year prospective comparative study of three topical beta blockers in the management of primary open angle glaucoma

Chemical Insights into Topical Agents in Intraocular Pressure Management: From Glaucoma Etiopathology to Therapeutic Approaches

Glaucoma encompasses a group of optic neuropathies characterized by complex and often elusive etiopathology, involvihttng neurodegeneration of the optic nerve in conjunction with abnormal intraocular pressure (IOP). Currently, there is no cure for glaucoma, and treatment strategies primarily aim to halt disease progression by managing IOP. This review delves into the etiopathology, diagnostic methods, and treatment approaches for glaucoma, with a special focus on IOP management. We discuss a range of active pharmaceutical ingredients used in glaucoma therapy, emphasizing their chemical structure, pharmacological action, therapeutic effectiveness, and safety/tolerability profiles. Notably, most of these therapeutic agents are administered as topical formulations, a critical aspect considering patient compliance and drug delivery efficiency. The classes of glaucoma therapeutics covered in this review include prostaglandin analogs, beta blockers, alpha agonists, carbonic anhydrase inhibitors, Rho kinase inhibitors, and miotic (cholinergic) agents. This comprehensive overview highlights the importance of topical administration in glaucoma treatment, offering insights into the current state and future directions of pharmacological management in glaucoma.

Intraocular Pressure Reduction by Femtosecond Laser Created Trabecular Channels in Perfused Human Anterior Segments

Purpose

This study investigated the initial feasibility of using femtosecond laser trabeculotomy (FLT) to create open channels through the trabecular meshwork into Schlemm's canal to lower intraocular pressure (IOP) in a perfused anterior segment model.

Methods

Human anterior segments (12 eyes) were assigned to either treatment (n = 6) or sham treatment (n = 6) groups. Both groups were perfused until a baseline IOP was recorded upon which a direct FLT treatment or a sham treatment was administered. IOP was recorded before and after the treatment. Spectral domain optical coherence tomography and second harmonic generation imaging we used to investigate the FLT channels.

Results

In the FLT group, there was a significant mean decrease in the IOP of 22% compared with the pre-FLT IOP (7.13 ± 2.95 mm Hg to 5.34 ± 1.62 mm Hg; P < 0.05). In the control group, the post-sham IOP remained relatively unchanged compared with the pre-sham IOP (6.39 ± 3.69 mm Hg to 6.67 ± 4.12 mm Hg).

Conclusions

The results of this study indicate that FLT treatment can significantly decrease the IOP in a perfusion model and may provide a potential noninvasive treatment option for primary open angle glaucoma.

Translational Relevance

Investigating the use of femtosecond lasers for photodisrupting the trabecular meshwork can lead to a clinically relevant alternative to current glaucoma procedures.

Lipase Catalyzed Synthesis of Enantiopure Precursors and Derivatives for β-Blockers Practolol, Pindolol and Carteolol

Sustainable methods for producing enantiopure drugs have been developed. Chlorohydrins as building blocks for several β-blockers have been synthesized in high enantiomeric purity by chemo-enzymatic methods. The yield of the chlorohydrins increased by the use of catalytic amount of base. The reason for this was found to be the reduced formation of the dimeric by-products compared to the use of higher concentration of the base. An overall reduction of reagents and reaction time was also obtained compared to our previously reported data of similar compounds. The enantiomers of the chlorohydrin building blocks were obtained by kinetic resolution of the racemate in transesterification reactions catalyzed by Candida antarctica Lipase B (CALB). Optical rotations confirmed the absolute configuration of the enantiopure drugs. The β-blocker (S)-practolol ((S)-N-(4-(2-hydroxy-3-(isopropylamino)propoxy)phenyl)acetamide) was synthesized with 96% enantiomeric excess (ee) from the chlorohydrin (R)-N-(4-(3-chloro-2 hydroxypropoxy)phenyl)acetamide, which was produced in 97% ee and with 27% yield. Racemic building block 1-((1H-indol-4-yl)oxy)-3-chloropropan-2-ol for the β-blocker pindolol was produced in 53% yield and (R)-1-((1H-indol-4-yl)oxy)-3-chloropropan-2-ol was produced in 92% ee. The chlorohydrin 7-(3-chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one, a building block for a derivative of carteolol was produced in 77% yield. (R)-7-(3-Chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one was obtained in 96% ee. The S-enantiomer of this carteolol derivative was produced in 97% ee in 87% yield. Racemic building block 5-(3-chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one, building block for the drug carteolol, was also produced in 53% yield, with 96% ee of the R-chlorohydrin (R)-5-(3-chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one. (S)-Carteolol was produced in 96% ee with low yield, which easily can be improved.

Current and new pharmacotherapeutic approaches for glaucoma

INTRODUCTION

Glaucoma is the leading cause of irreversible blindness worldwide. Medical therapy is the main line of treatment of open-angle glaucoma (OAG) and ocular hypertension. Despite the expansion of the glaucoma lineup with the newly approved medication classes, many barriers and issues still exist with topical therapy. Novel non-topical drug delivery may address such issues, adding more options to glaucoma pharmacotherapy.

AREAS COVERED

This review outlines current topical therapies for glaucoma, in addition to new medications under trials. The issues with topical therapy, in general, are discussed, as well as the new non-topical drug delivery systems. The authors performed a comprehensive search for published studies on glaucoma medical therapy using the electronic database of PubMed and manual search for each medication and non-topical delivery options. The extra- and intraocular delivery methods and the new topical glaucoma medications under research are covered.

EXPERT OPINION

Medical management of glaucoma represents a challenge for both patients and clinicians. Noncompliance (e.g. difficulty with administering the eye drops), cost, side effects, and intraocular pressure fluctuation are the major problems with topical therapy. To overcome such barriers, research should continue in developing new medications and innovation of non-topical drug delivery systems.

A comparative study on efficacy of fixed combination timolol/brinzolamide versus travoprost monotherapy in drug-naïve open-angle glaucoma patients

Background

Glaucoma is most common irreversible cause of blindness in India. First line management of open-angle glaucoma is either beta blockers or prostaglandin analogs monotherapy. Monotherapy rarely achieves target intraocular pressure within 2 years and patients are shifted to combination medications, usually fixed-dose combination.

Objective

To compare travoprost monotherapy and timolol/brinzolamide fixed-dose combination for their intraocular pressure lowering efficacy, their effects on hemodynamic parameters and cup disc ratio reversibility in newly diagnosed drug-naïve open-angle glaucoma patients.

Material and methods

In a 12-week, prospective, randomised, single-blind study, patients were randomised to receive twice daily 0.5% timolol and 0.2% brinzolamide fixed-dose combination (n = 52) or once daily travoprost 0.004% (n = 52). Intraocular pressure, blood pressure, pulse rate and cup disc ratio were compared across treatment groups over 3 months.

Results

Significant reduction (p < 0.001) in intraocular pressure by 27.99% and 30.49% at 12th-week visit as compared with baseline was observed in monotherapy and fixed-dose combination group, respectively. Significant changes in pulse rate (9 beats/min) and systolic blood pressure (2.35 mmHg) was observed in fixed-dose combination group. No cup disc ratio reversibility was observed at the end of study. Conjunctival hyperaemia (n = 14) and transient blurring of vision (n = 16) were most commonly reported adverse drug reaction in monotherapy and fixed-dose combination, respectively.

Conclusion

The 0.5% timolol and 0.2% brinzolamide fixed-dose combination produced greater reduction in intraocular pressure than those produced by 0.004% travoprost alone in drug-naïve open-angle glaucoma patients.

Prescribing Trends of Topical Glaucoma Medications in Australia From 2001 to 2017

PRECIS

As new glaucoma treatments arise, including minimally invasive glaucoma surgeries and new classes of glaucoma medications, it is important to examine the prescription trends of current topical glaucoma medications and how they may change.

PURPOSE

To determine the prescribing trends of topical glaucoma medications in Australia from 2001 to 2017.

METHODS AND ANALYSIS

Pharmaceutical Benefits Scheme (PBS) item numbers were used to determine glaucoma medication prescribing rates from 2001 to 2017. All data were adjusted for population (/100,000) as per the Australian Bureau of Statistics (ABS) population data.

RESULTS

Overall prescription rates for glaucoma medications ranged between 67,904 and 86,936 per 100,000 from 2001 to 2017. An upward trend was noted from 2001 to 2015, with the exception of a notable decline in 2013 by 14.7%, before then increasing by 13.7% in 2014. After 2015, prescribing rates were seen to decrease over the subsequent years in the study period. Latanoprost remained the most prescribed medication and prostaglandin the most prescribed class. Prescribing rates of single-agent beta-blockers were noted to decrease during the 17-year period, particularly with the introduction of combination agents, which note an upward trend. Brinzolamide/brimonidine has increased by 50.0% from 2016 to 2017.

CONCLUSIONS

Total rates of prescriptions have remained relatively stable from 2001 to 2017. The number of medications prescribed when considering combination agents separately was seen to be increasing from 2001 to 2015. From 2015 to 2017, a downward trend was noted in the number of medications prescribed. Prostaglandins remain the most prescribed class throughout the study period.

Fixed-combination treatments for intraocular hypertension in Chinese patients - focus on bimatoprost-timolol

Glaucoma is a common eye disease that can lead to irreversible vision loss if left untreated. The early diagnosis and treatment of primary open-angle glaucoma is challenging, and visual impairment in Chinese glaucoma patients is a serious concern. Most of these patients need more than one topical antiglaucoma agent to control their intraocular pressures (IOPs). In the People’s Republic of China, the daily cost of different glaucoma medication varies greatly, and the treatment habits differ throughout the country. Prostaglandin analogs (PGAs) are recommended as first-line monotherapy, because of their efficacy and low risk of systemic side effects. Fixed-combination drops, particularly PGA-based fixed combinations, have recently been developed and used in patients with progression or who have failed to achieve their target IOPs. Here, we reviewed the current literature on the use of bimatoprost-timolol fixed combination (BTFC) in the People’s Republic of China. BTFC has achieved good efficacy and tolerability in Chinese clinical trials. In addition, BTFC is more cost effective compared with other fixed combinations available in the People’s Republic of China. Fixed-combination drops may offer benefits, such as keeping the ocular surface healthy, convenience of administration, and improvement in long-term adherence and quality of life. Therefore, BTFC has great potential for the treatment of Chinese glaucoma patients. However, the long-term efficacy of BTFC, comparisons of BTFC with other fixed-combination drugs, and treatment adherence and persistence with treatment in Chinese patients are unknown and will require further study.

Pointwise linear regression analysis of serial Humphrey visual fields and a correlation with electroretinography in birdshot chorioretinopathy

AIMS

To investigate deterioration in serial Humphrey visual fields (HVFs) using pointwise linear regression (PLR) analysis in patients with birdshot chorioretinopathy (BCR) monitored with full field electroretinography (ERG).

METHODS

Retrospective review of the case notes, HVFs and ERG of patients under treatment for BCR at Moorfields Eye Hospital between 1998 and 2014. Eyes with ERG recorded using protocols to incorporate International Society for Clinical Electrophysiology of Vision standards and at least five reliable Swedish Interactive Testing Algorithm standard 24-2 HVFs were included. HVFs were analysed by PLR analysis of luminance sensitivity using the Progressor software and linear regression analysis of mean deviation (MD).

RESULTS

202 HVFs from 31 eyes of 16 patients were analysed. Mean follow-up was 60.25 months. MD remained stable in all eyes. PLR analysis detected progressive field loss in 10 eyes (seven patients). The mean (SD) slope of change at progressing points was -1.83 (0.90) db/year (p<0.05). ERG worsened in 3 of the 10 eyes with field loss. Although there was no clear relationship between patterns of field loss and electrophysiological dysfunction, more extensive field loss was associated with more marked ERG abnormalities and rod system involvement.

CONCLUSIONS

This study demonstrates that PLR analysis can identify field loss despite a stable MD and stable and even normal electrophysiology in BCR, thus establishing a role for regular standardised monitoring of visual fields as an adjunct to electrophysiology in order to facilitate more accurate characterisation of retinal dysfunction and hence enabling better-informed treatment decisions and monitoring of treatment efficacy.

Efficacy and safety of brinzolamide/timolol fixed combination compared with timolol in Japanese patients with open-angle glaucoma or ocular hypertension

Purpose

To evaluate the efficacy and safety of brinzolamide 1%/timolol 0.5% fixed-combination (BRINZ/TIM-FC) therapy compared with timolol 0.5% (TIM) monotherapy in Japanese patients with open-angle glaucoma or ocular hypertension.

Methods

This randomized, double-masked, multicenter study included Japanese patients aged ≥20 years. Patients were treated during a 4-week observation period with TIM monotherapy in advance of randomization to treatment with topical BRINZ/TIM-FC or TIM monotherapy twice daily for 8 weeks. The primary endpoint was mean reduction in intraocular pressure (IOP) from baseline to week 8 at 2 hours postinstillation. Adverse events (AEs) were recorded at each visit.

Results

A total of 301 patients (BRINZ/TIM-FC, n=150; TIM, n=151; age [mean ± standard deviation], 61±13 years) were enrolled. Mean IOP reductions from baseline were greater with BRINZ/TIM-FC than with TIM at weeks 4 and 8 at 0 and 2 hours postinstillation (all P≤0.0001), with mean reductions of −3.2 mmHg with BRINZ/TIM-FC and −1.4 mmHg with TIM at week 8, 2 hours postinstillation. Although AEs were observed in 19% of all patients (BRINZ/TIM-FC, 20%; TIM, 19%), all AEs were mild or moderate.

Conclusion

BRINZ/TIM-FC therapy was associated with significantly greater reductions in IOP compared with TIM, and it was well tolerated in Japanese patients with open-angle glaucoma or ocular hypertension.

Current primary open-angle glaucoma treatments and future directions

Primary open-angle glaucoma (POAG) is a leading cause of blindness with no known cure. Management of the disease focuses on lowering intraocular pressure (IOP) with current classes of drugs like prostaglandin analogs, beta-blockers, alpha-agonists, and carbonic anhydrase inhibitors. These treatments have not helped all patients. Some patients continue to experience deterioration in the optic nerve even though their IOPs are within the normal range. New views have surfaced about other pathophysiological processes (such as oxidative stress, vascular dysfunction, and retinal cell apoptosis) being involved in POAG progression, and adjunctive treatments with drugs like memantine, bis(7)-tacrine, nimodipine, and mirtogenol are advocated. This review examines the current and proposed treatments for POAG. Some of the proposed drugs (bis(7)-tacrine, nimodipine, vitamin E, and others) have shown good promise, mostly as monotherapy in various clinical trials. It is recommended that both the current and proposed drugs be put through further robust trials in concurrent administration and evaluated.

Balancing efficacy and tolerability of prostaglandin analogues and prostaglandin-timolol fixed combinations in primary open-angle glaucoma

BACKGROUND

Lowering intraocular pressure (IOP) is currently the only therapeutic approach that preserves visual function in primary open-angle glaucoma. In making treatment decisions for first- and second-line therapy, the clinician needs to provide an appropriate balance of efficacy and tolerability. Prostaglandin analogues (PGAs) are frequently used as first-line monotherapy, because of their efficacy and low risk of systemic side effects. Similarly, PGA-based fixed combinations are frequently used in patients who progress or fail to achieve the target IOP.

SCOPE

We have reviewed the literature on the management of primary open-angle glaucoma with PGAs, both as monotherapies and in fixed combinations.

FINDINGS

In the clinical trial and meta-analysis data identified, bimatoprost 0.03% seems to be associated with a greater overall ability to lower IOP compared with latanoprost, travoprost or tafluprost, at the cost of a slightly higher incidence of conjunctival hyperaemia. Studies indicate that patients' adherence to treatment is generally better with PGAs than with many other monotherapies. In patients requiring more than one IOP-lowering agent, fixed combination treatments may provide improved adherence and tolerability benefits compared with concomitant use of individual treatments. Bimatoprost/timolol fixed combination appears to be slightly more efficacious than latanoprost/timolol or travoprost/timolol, and tolerability differences between the fixed combinations appear to be slight, probably because the addition of timolol to the PGA component lessens the associated hyperaemia. Surveys on EU physician attitudes appear largely in line with these clinical data.

CONCLUSION

An appropriate balance between efficacy and tolerability ensures optimum IOP lowering and reduces the risk of non-adherence. PGAs largely fulfil this need as monotherapies and as components of combinations.

Visual field loss in patients with normal-tension glaucoma under topical nipradilol or timolol: subgroup and subfield analyses of the nipradilol-timolol study

PURPOSE

To estimate the deterioration rates of visual field loss in Japanese normal-tension glaucoma (NTG) patients under either topical nipradilol or timolol, and to explore intergroup differences in the treatment results.

METHODS

A total of 146 NTG patients with mild to moderate damage were randomized to either nipradilol or timolol and followed for 3 years with a periodic comprehensive ophthalmological visual field examination (30-2 Humphrey perimeter program) every 6 months (the Nipradilol-Timolol Study). The time course of mean deviation (MD), the average total deviation (TD(mean)) in four subfields, and the corrected pattern standard deviation (CPSD) were compared between the two groups using regression analysis with a linear mixed effect model.

RESULTS

The estimated slope for MD (dB/year) was -0.03 in the nipradilol and -0.05 in the timolol group (P > 0.4). In both groups, TD(mean) in the superior-central subfield and CPSD showed significant changes (-0.3 and 0.2-0.3, P <or= 0.001). In the patients with early visual field loss or those younger than 40 years, deterioration of some visual field parameters tended to be slower in the nipradilol group than in the timolol group.

CONCLUSION

During 3 years of monotherapy with either nipradilol or timolol in NTG patients, only TD(mean) in the superior-central subfield and the CPSD changed significantly without any intergroup differences.

Pharmacotherapy of intraocular pressure: part I. Parasympathomimetic, sympathomimetic and sympatholytics

Elevated intraocular pressure (IOP) has been recognized as the major risk factor for the development of glaucoma and a wide range of options are now available to reduce it: medical treatment, laser, filtering, or cyclodestructive surgery (alone or in combination). All these modalities act by decreasing eye pressure and, thereby, protecting the optic nerve head from a mechanic direct and/or vascular indirect insult. Topical medical therapy represents the first-choice treatment and, in most cases, it effectively controls IOP, avoiding the occurrence of further optic nerve damage. All medications lower IOP in two main ways: decreasing the production of aqueous humour or by increasing its outflow from the eye. Consequently, antiglaucoma drugs either suppress aqueous humour formation (beta-adrenergic antagonists, carbonic anhydrase inhibitors, and alpha-2-adrenergic agonists) or raise aqueous humour outflow throughout the conventional (e.g., pilocarpine) or uveoscleral (prostaglandin FP receptor agonists, and prostamides) route. In addition, fixed and unfixed combinations of antiglaucoma compounds have also been available for patients requiring more than one type of medication. This review, which is part one of two (please see Expert Opinion on Pharmacotherapy 10 (17)) briefly considers the characteristics of sympathomimetic, sympatholytics and parasympathomimetic commonly employed in the medical treatment of glaucoma, mainly the primary open-angle form, focusing the discussion on the clinical evidence supporting the use of these three classes of compound.

Intraocular pressure-lowering efficacy of brinzolamide 1%/timolol 0.5% fixed combination compared with brinzolamide 1% and timolol 0.5%

PURPOSE

To compare the safety and intraocular pressure (IOP)-lowering efficacy of brinzolamide 1%/timolol 0.5% fixed combination with brinzolamide 1% or timolol 0.5% alone in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT).

DESIGN

Randomized, double-masked, parallel group, multicenter study.

PARTICIPANTS

Five hundred twenty-three patients were randomized to the study treatments.

METHODS

Patients with OAG or OHT were recruited to the study. Qualifying eyes had IOPs of 24 to 36 mmHg at 8 am and 21 to 36 mmHg at 10 am on 2 eligibility visits after an appropriate washout period from previous treatment. Patients were assigned randomly to either brinzolamide 1%/timolol 0.5%, brinzolamide 1% (Azopt; Alcon Laboratories, Fort Worth, TX), or timolol 0.5%, dosed twice daily and were followed up while receiving therapy for 6 months. At selected sites, additional IOP measurements were performed at 12 pm, 4 pm, and 8 pm during the 2 eligibility visits, at month 3, and at month 6.

MAIN OUTCOME MEASURE

Mean IOP.

RESULTS

Brinzolamide 1%/timolol 0.5% produced statistically significant and clinically relevant reductions from baseline ranging from 8.0 to 8.7 mmHg, which were statistically and clinically superior to that of either brinzolamide 1% (5.1-5.6 mmHg) or timolol 0.5% (5.7-6.9 mmHg). No safety concerns were identified based on an assessment of ocular and cardiovascular parameters and a review of adverse events.

CONCLUSIONS

Brinzolamide 1%/timolol 05% is superior in IOP-lowering efficacy to either brinzolamide 1% or timolol 0.5%.

Medical interventions for primary open angle glaucoma and ocular hypertension

BACKGROUND

Primary open angle glaucoma (POAG) is a progressive optic neuropathy with an elevated intraocular pressure (IOP), where the optic nerve head becomes pathologically excavated and the visual field (VF) is characteristically altered. Ocular hypertension (OHT) is a condition with elevated IOP but without discernible pathology of the optic nerve head or the VF. It is a major risk factor for development of POAG.

OBJECTIVES

To assess and compare the effectiveness of topical pharmacological treatment for POAG or OHT to prevent progression or onset of glaucomatous optic neuropathy.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE and EMBASE in May 2007. We searched the bibliographies of identified articles and contacted experts, investigators and pharmaceutical companies for additional published and unpublished studies.

SELECTION CRITERIA

Randomised controlled trials comparing topical pharmacological treatment to placebo, no treatment or other treatment for specified endpoints which included people with POAG or OHT, and with duration of treatment of at least one year.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed trial quality. Where appropriate, we summarised data using Peto odds ratio and mean difference after testing for heterogeneity between studies.

MAIN RESULTS

We included 26 trials, which randomised 4979 participants, in this review. Meta-analysis of 10 trials clearly demonstrated reduction of onset of VF defects in treated OHT (OR 0.62, 95% CI 0.47 to 0.81). No single drug showed a significant VF protection compared to placebo or untreated controls. We did identify some border line evidence for a positive influence of treatment on VF prognosis (OR 0.67, 95% CI 0.45 to 1.00) for the beta-blockers .

AUTHORS' CONCLUSIONS

The results of this review support the current practice of IOP lowering treatment of OHT. A visual field protective effect has been clearly demonstrated for medical IOP lowering treatment. Positive but weak evidence for a beneficial effect of the class of beta-blockers has been shown. Direct comparisons of prostaglandins or brimonidine to placebo are not available and the comparison of dorzolamide to placebo failed to demonstrate a protective effect. However, absence of data or failure to prove effectiveness should not be interpreted as proof of absence of any effect. The decision to treat a patient or not, as well as the decision regarding the drug with which to start treatment, should remain individualised, taking in to account the amount of damage, the level of IOP, age and other patient characteristics.

The rising cost of glaucoma drugs in Ireland 1996-2003

BACKGROUND

Glaucoma affects approximately 2% of the population in developed countries and is estimated to affect 67 million people worldwide. The authors investigated the effect of the introduction of new medications on the volume and cost of drugs for glaucoma in two countries, Northern Ireland (NI, population approximately 1.7 million) and the Republic of Ireland (ROI, population approximately 3.9 million) in the 8 years from 1996 to 2003. They also looked at the surgical rates for glaucoma within the same time period for the two countries.

METHODS

A retrospective analysis was performed of drug costs, prescribing data, and operation rates for glaucoma in Ireland from January 1996 to December 2003. Information regarding costs and volume were obtained for each type of glaucoma drug and these were then grouped into the glaucoma treatment subsections as found in the British National Formulary. The drug information was obtained from the Central Services Agency in NI and IMS Health in the ROI and included both public and private prescriptions. The information on surgical rates for glaucoma was obtained from the Department of Health and Social Services in NI and the Hospital In-patient Enquiry (HIPE) data national files in the ROI.

RESULTS

There was a 30% increase in prescription items for glaucoma in NI and a 59% increase in the ROI from 1996 to 2003. The costs increased more rapidly than the number of items: 227% in the ROI and 78% in NI from January 1996 to December 2003. In the ROI, there was an average 19% year on year increase in costs. In NI, new drugs accounted for 40% of the quantity of prescription items for glaucoma and 63% of the market cost in 2003. In the ROI new drugs accounted for 57% of the quantity and 77% of the market cost for glaucoma in 2003; prostaglandin analogue drugs alone accounted for 53% of the cost. The number of trabeculectomies performed decreased by more than 60% in both countries.

CONCLUSION

Volume and cost of glaucoma drugs increased dramatically in both NI and the ROI from 1996 to 2003, probably the result of a combination of changing demographics and a changing approach towards the management of patients with glaucoma and ocular hypertension. In 2003 in the ROI, prostaglandin analogues were the most commonly prescribed class of drug for patients with glaucoma and/or ocular hypertension causing a profound rise in drug expenditure.

Clinical Outcomes of Glaucoma Treatments Over a Patient Lifetime

PURPOSE

To quantify the clinical outcome of glaucoma treatment over a patient's lifetime to identify treatment parameters that would preserve vision across a population.

METHODS

A Markov model was used to reproduce glaucoma treatments and clinical responses over a patient's lifetime. Markov states comprised first-line to fourth-line pharmacological treatments, no treatment, laser therapy, surgery, blindness, and death. All patients began with first-line treatment and passed to the next treatment in line following a failure. After each failure, and always after a fourth-line failure, patients could receive laser therapy or surgery, followed by no treatment or a new first-line treatment. Transitional probabilities came from a cross-sectional study and national statistics. Sensitivity analyses were based on second order Monte-Carlo simulation.

RESULTS

Cohort demographics were average age 59.7 years, life expectancy 22.5 years, females 54.0%. Treatment durations (months) for a patient with ocular hypertension were first-line (89), second-line (49), third-line (41), and no treatment (44); laser interventions numbered 1.251 and surgical 0.882. For a patient with glaucoma the corresponding values were 70, 44, 40, 18, 42, 1.197, and 0.842. First-line or second-line drugs best at controlling intraocular pressure (IOP) reduced laser therapy, surgery, and the prevalence of blindness. The most effective drug should be prescribed first-line. According to our model drugs specifically able to arrest disease progression would be more beneficial than intraocular pressure control.

CONCLUSION

More powerful glaucoma medication (first-line or second-line) would contribute to the preservation of long-term vision.

Are there any benefits of Betoptic S (betaxolol HCl ophthalmic suspension) over other beta-blockers in the treatment of glaucoma?

The cardioselective beta-blocker, betaxolol, is an effective ocular antihypertensive agent. Its mode of action in lowering intraocular pressure is similar to that of the nonselective blockers, by suppressing the flow of aqueous humor. The most frequent adverse reaction to betaxolol is stinging upon administration, which is minimised by an ocular suspension with a similarly effective twofold reduced concentration (Betoptic S, 0.25%). The extent of beta 1-adrenoceptor occupancy of topically applied betaxolol in the systemic circulation is less than that of the nonselective blockers and beta 2-receptor occupancy is negligible, providing a better safety profile in patients with cardiopulmonary disease. Experimental studies have revealed that the drug reaches the retina after topical administration and displays a voltage-dependent L-type calcium channel blocking activity, which probably allows betaxolol to improve retinal perfusion and to serve as a neuroprotective agent recommendable in various forms of glaucoma.

Reducing intraocular pressure: is surgery better than drugs?

Reducing IOP is presently the evidence based, most accepted and most practised therapeutical approach for glaucoma patients. Currently topical ocular hypotensive medications, with its different classes, as well as filtering surgery (trabeculectomy and non-penetrating glaucoma surgery) are in the forefront of therapeutic modalities for IOP reduction. This article looks at the potential advantages and disadvantages of topical medications versus filtering surgery. It does not directly address the question of initial treatment of glaucoma, or what is the better treatment of glaucoma, as other review articles had, but rather looks in a more specific on the pros and the cons of each in relation to IOP reduction. In other words this article deals with the situation once the decision has been made to reduce IOP.

A 3-month randomized controlled trial of bimatoprost (LUMIGAN) versus combined timolol and dorzolamide (Cosopt) in patients with glaucoma or ocular hypertension

PURPOSE

To compare the efficacy and safety of topical bimatoprost (LUMIGAN; Allergan, Inc., Irvine, CA) once daily with that of topical combined timolol and dorzolamide (Cosopt; Merck and Co, Inc., Whitehouse Station, NJ) twice daily.

DESIGN

Prospective, randomized, double-masked, multicenter clinical trial.

PARTICIPANTS

One hundred seventy-seven patients with a diagnosis of glaucoma or ocular hypertension and inadequate control of intraocular pressure (IOP) after at least 2 weeks of topical timolol maleate 0.5% monotherapy.

METHODS

Patients were randomized to receive bimatoprost 0.03% once daily (n = 90) or combined timolol 0.5% and dorzolamide 2% twice daily (n = 87) over a 3-month period.

MAIN OUTCOME MEASURES

Intraocular pressure, the primary end point, was measured at 8 AM and 10 AM at baseline, week 1, and months 1, 2, and 3, and also at 4 PM and 8 PM at baseline and month 3.

RESULTS

Bimatoprost provided significantly greater IOP lowering compared with combined timolol and dorzolamide. At the 8 AM measurements, bimatoprost lowered mean IOP 6.8 mmHg to 7.6 mmHg from baseline, whereas combined timolol and dorzolamide lowered mean IOP 4.4 to 5.0 mmHg from baseline (P<0.001). At the last follow-up, patients had better diurnal IOP control with bimatoprost than combined timolol and dorzolamide. At 8 AM at the 3-month visit, the percentages of patients achieving IOPs of <or =13 mmHg, < or =14 mmHg, < or =15 mmHg, or < or =16 mmHg were more than twice as high for bimatoprost than for combined timolol and dorzolamide (all P< or =0.008). Taste perversion, ocular burning, and stinging with instillation were more common with combined timolol and dorzolamide, whereas conjunctival hyperemia was more common with bimatoprost.

CONCLUSIONS

In individuals with glaucoma or ocular hypertension, uncontrolled on a topical beta-blocker alone, bimatoprost lowered IOP more consistently than did combined timolol and dorzolamide.

Is ophthalmology evidence based? A clinical audit of the emergency unit of a regional eye hospital

AIM

To evaluate the proportion of interventions that are evidence based in the acute care unit of a regional eye hospital.

METHODS

A prospective clinical audit was carried out at Hong Kong Eye Hospital in July 2002 to investigate the extent to which ophthalmic practices were evidence based. The major diagnosis and intervention provided were identified through chart review. A corresponding literature search using Medline and the Cochrane Library was performed to assess the degree to which each intervention was based on current, best evidence. Each diagnosis intervention pair was accordingly analysed and graded. The level of best, current evidence supporting each intervention was graded and analysed.

RESULTS

A total of 274 consecutive consultation episodes were examined. 22 cases were excluded since no diagnosis or intervention was made during the consultation. 108 (42.9%) patient interventions were found to be based on evidence from systematic reviews, meta-analyses, or randomised controlled trials (RCT). Evidence from prospective or retrospective observational studies supported the interventions in 86 (34.1%) patients. In 58 (23.0%) cases, no evidence or opposing evidence was found regarding the intervention. The proportion of evidence based on RCT or systematic reviews was higher for surgical interventions compared with non-surgical interventions (p=0.007). The proportion of interventions based on RCT or systematic reviews was higher for specialist ophthalmologists than trainee ophthalmologists (p=0.021).

CONCLUSION

This study demonstrated that the majority of interventions in the ophthalmic unit were evidence based and comparable to the experience of other specialties.

The effect of latanoprost on intraocular pressure during 2 years of treatment

Our objective was to study the intraocular pressure (IOP) in open-angle glaucoma or ocular hypertensive patients during long-term treatment with latanoprost. A total of 532 patients treated with 0.005% latanoprost were enrolled, including 493 and 113 patients treated for 6 and 24 months, respectively. Mean IOP was analyzed with the analysis of variance technique. The risk of treatment failure was analyzed with survival analysis technique. After 2 weeks of latanoprost treatment, the mean IOP was reduced 8.2 (32%) and 8.9 (34%) mm Hg in the subgroups of patients treated for 6 and 24 months, respectively. The change in mean IOP during 2 years of latanoprost treatment was not statistically significant (p = 0.15). Patients with primary open-angle glaucoma or ocular hypertension showed an 86% and 97% chance of receiving a sufficient IOP reduction with latanoprost (p < 0.01), repectively. The initial mean IOP reduction was maintained throughout the 2 years of treatment.

Short- and long-term safety of glaucoma drugs

Glaucoma, a leading cause of blindness worldwide, is a chronic neurodegenerative disorder. Patients with glaucoma may require long-term administration of intraocular pressure (IOP)-lowering medications. These medications belong to several classes of molecules including beta-adrenergic blockers, cholinergic agents, alpha-adrenergic agonists, carbonic anhydrase inhibitors and ocular hypotensive lipids. Most adverse effects associated with IOP-lowering medications are mild and ocular in nature; however, several of them are associated with systemic risks as well as serious ocular effects, especially following chronic use. The following review discusses the acute and long-term effects of commonly used IOP-lowering medications.