Topical epinephrine in glaucoma suspects

Risk Calculation in the Medication Arm of the Ocular Hypertension Treatment Study

PURPOSE

Risk assessment is integral to the management of individuals with ocular hypertension (OHTN). This study aims to determine the predictive accuracy of the Ocular Hypertension Treatment Study 5-year risk calculator (OHTS calculator) among treated patients with OHTN by applying it to patients randomized to the Ocular Hypertension Treatment Study (OHTS) medication arm.

DESIGN

Post hoc secondary analysis of a randomized clinical trial.

SUBJECTS

Individuals participating in the OHTS who were randomized to the medication arm. Only participants with complete baseline data in both eyes were included (n = 726).

METHODS

The hazard ratios (HRs) of the medication group in OHTS were compared to the HR used for the OHTS calculator using the z-test statistic to establish the OHTS calculator's generalizability to the OHTS medication arm. The performance of the OHTS calculator among the OHTS medication group was evaluated twice, using both untreated baseline intraocular pressure (IOP) and average treated IOP during the first 24 months for the IOP variable.

MAIN OUTCOME MEASURES

The performance was determined based on the model's accuracy in estimating the risk of reaching an OHTS primary open-angle glaucoma (POAG) end point using calibration chi-square and discriminating between participants who did or did not develop POAG.

RESULTS

The HRs for the OHTS medication arm were not significantly different from those used in the OHTS calculator for untreated OHTN derived from observation arm data (P > 0.1). Based on the calibration chi-square test for the medication group, the OHTS calculator prediction model had good predictive accuracy when using the mean treated IOP and poorer predictive accuracy with the untreated baseline IOP (chi-square 10 and 29, respectively). The model had good discrimination with treated IOP (c-statistic = 0.77), comparable to what has been reported for the OHTS calculator in the OHTS observation group.

CONCLUSIONS

The OHTS calculator can be applied to treated patients with OHTN, and repeat risk calculation after initiating IOP reduction may provide useful information that can aid in disease management.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Autonomic drugs in the treatment of canine and feline glaucoma – Part I: Medications that lower intraocular pressure by increasing the outflow of aqueous humour

One characteristic of the most common types of glaucoma is increased intraocular pressure (IOP), which has a damaging effect on optic nerve axons, leading to progressive loss of retinal ganglion cells. Therefore, ocular hypotensive drugs are the mainstay of pharmacological therapy for glaucoma. This review article, which is the first part of a two-part series, is dedicated to autonomic drugs which lower IOP by increasing the outflow of aqueous humour. These agents are subdivided into two groups: (a) drugs that lower IOP by increasing the trabecular outflow and the uveoscleral outflow (i.e. nonselective adrenergic agonists), and (b) medications that lower IOP by opening of the drainage angle and by increasing the conventional outflow via the trabecular outflow (i.e. parasympathomimetics). This paper summarizes the current state of knowledge on the mechanism of action of these drugs and their effect on IOP in dogs and cats. Moreover, it discusses possible undesirable side effects of these medications and presents the current ideas about their role and position in the medical management of glaucoma in small animals

Quantifying the effect of intraocular pressure reduction on the occurrence of glaucoma

PURPOSE

To estimate the effect of reducing intraocular pressure (IOP) on: (i) the incidence of primary open-angle glaucoma (POAG) in patients with ocular hypertension (OH), and (ii) the progression of glaucoma.

METHODS

A meta-analysis of relevant randomized controlled trials was conducted. A literature search was performed to identify trials with: a randomized comparison of IOP-lowering intervention versus placebo or no treatment; visual field loss or optic disc changes as outcome; and follow-up >6 months. A pooled relative risk (RR) was calculated by a random effects model. Risk reduction of glaucoma conversion per mmHg of IOP reduction was quantified in a meta-regression model.

RESULTS

We identified nine OH and one POAG trials. A meta-analysis of OH trials gives a pooled RR of 0.61 [95% confidence interval (CI) 0.45-0.83]. A meta-regression shows a decrease of the RR of glaucoma conversion by 14% with each mmHg extra IOP reduction (P = 0.045). No meta-analysis of POAG trials was performed because only one study has been identified.

CONCLUSION

There is sufficient evidence that OH therapy reduces the risk of conversion to glaucoma. This risk reduction increases with greater IOP reduction.

Treating ocular hypertension to reduce glaucoma risk: when to treat?

When to treat the patient who presents with ocular hypertension has been a question that has 'stumped' the ophthalmic community for decades. Population-based studies and intervention trials have provided the basis for understanding why we consider treating such patients. Although the EGPS (European Glaucoma Prevention Study) did not demonstrate that reducing intraocular pressure (IOP) with dorzolamide prevented the onset of glaucoma compared with individuals receiving a placebo, the investigators of the OHTS (Ocular Hypertension Treatment Study) found that the treatment of ocular hypertension can be delayed with topical medication when treated patients were compared with an observation group. There are differences in inclusion criteria, study design and retention rates between the EGPS and the OHTS, which may have led to the discrepancies in outcomes between these two studies. These differences provide a basis for understanding the relevance of the findings of both trials to clinical practice. The clinician should consider key risk factors such as age, thin corneal thickness measurements, large cup-to-disc ratio and mean IOP when determining who should be treated. However, the ultimate decision of when to treat will be determined by other issues such as life expectancy, the general health of the patient and the number of risk factors. Clearly, the treatment of only high-risk patients with ocular hypertension should be considered.

An evidence-based assessment of risk factors for the progression of ocular hypertension and glaucoma

PURPOSE

To critically review the existing literature concerning risk factors for progression of ocular hypertension and glaucoma to assist in assigning levels of risk for individual patients.

DESIGN

Evidence-based review.

METHODS

A panel of physicians specializing in treatment of glaucoma patients was convened to critically analyze published population-based studies of ocular hypertension and glaucoma progression. The strength of evidence in support of reported risk factors was weighed.

RESULTS

Many putative risk factors for progression of ocular hypertension or glaucoma have been reported in the literature. The risk factors most strongly supported by evidence are higher intraocular pressure (IOP), greater cup-to-disk ratio, thinner central corneal measurement, and older age. Black race does not appear to be an independent risk factor, although black individuals tend to have thinner corneas, greater cup-to-disk ratios, and higher IOP, which increase their risk. The limited number of studies in which other suspected risk factors are reported prevents drawing firm conclusions about their importance at this time.

CONCLUSIONS

Only a subset of patients with ocular hypertension will eventually develop glaucoma. Decisions regarding the implementation and extent of therapy for ocular hypertension can be difficult and require an understanding of the relative importance of risk factors for progression. This review discusses the strength of evidence supporting reported risk factors and may be useful in assessing the risk for progression of individual patients.

Effects of multiple dosing of epinephrine on aqueous humor dynamics in human eyes

Numerous studies have provided conflicting evidence to explain the ocular hypotensive mechanism of action of epinephrine. Although epinephrine has been shown consistently to increase outflow facility, its effects on aqueous flow and uveoscleral outflow are not as clear. The purpose of this study was to clarify the effects of multiple doses of topical epinephrine on aqueous humor dynamics in human eyes. This was done by evaluating the four main parameters that determine steady state intraocular pressure. These parameters were assessed at baseline and after a week of twice-daily treatment of epinephrine hydrochloride 2% to one eye. Twenty-six human volunteers were enrolled in the study. Intraocular pressure was measured by pneumatonometry, aqueous flow and trabecular outflow facility by fluorophotometry, episcleral venous pressure by venomanometry and uveoscleral outflow by mathematical calculation. In epinephrine-treated eyes compared to baseline, intraocular pressure and aqueous flow were reduced from 21.2 +/- 0.3 to 17.1 +/- 0.2 mmHg (19%, p = .01) and 3.3 +/- 0.2 to 2.9 +/- 0.2 microl/min (12%, p = .03), respectively. Trabecular outflow facility obtained by fluorophotometry was increased from 0.18 +/- 0.02 to 0.26 +/- 0.03 microl/min/mmHg (44%, p = .02). Topical epinephrine did not significantly affect uveoscleral outflow or episcleral venous pressure. In conclusion, multiple topical doses of epinephrine lowered intraocular pressure in human volunteers by reducing aqueous humor formation and increasing trabecular outflow facility. The increase in uveoscleral outflow suggested by other studies was not observed.

Antiglaucoma medications: a review of safety and tolerability issues related to their use

BACKGROUND

Much experience has been gained with the use of older classes of antiglaucoma agents--topical beta-adrenergic-receptor antagonists, nonselective adrenergic-receptor agonists, oral carbonic anhydrase inhibitors, and cholinergic agents. In the past decade, new drugs and classes of drugs used to treat glaucoma have become available, including topical carbonic anhydrase inhibitors, prostaglandin analogues, and alpha2-adrenergic-receptor agonists. Extensive community-based use of antiglaucoma medications has led to an increased understanding of the acute and long-term safety and tolerability issues associated with their use.

OBJECTIVE

This paper reviews the side effects associated with the various classes of topical antiglaucoma drugs, with a particular focus on long-term safety issues.

Latanoprost treatment for glaucoma: effects of treating for 1 year and of switching from timolol. United States Latanoprost Study Group

PURPOSE

To determine the efficacy and safety of latanoprost treatment for 1 year in glaucoma patients, and to evaluate the effects of switching from timolol to latanoprost therapy.

METHODS

Latanoprost 0.005% was topically applied once daily without masking for 6 months in 223 patients with elevated intraocular pressure after previous treatment with latanoprost once daily or 0.5% timolol twice daily for 6 months in a multicenter, randomized, double-masked, parallel group study.

RESULTS

Compared with baseline values before treatment, a significant (P < .0001) diurnal reduction in intraocular pressure of 6 to 8 mm Hg was maintained with minimal fluctuation for the duration of treatment. When treatment was switched from timolol to latanoprost, intraocular pressure was reduced by 1.5 +/- 0.3 mm Hg (mean +/- SEM; 8% change in intraocular pressure; 31% of the intraocular pressure reduction produced by timolol; P < .001) compared with the change in intraocular pressure in patients remaining on latanoprost therapy. Of the patients initially enrolled, 95% successfully completed treatment. There was a slight overall increase in conjunctival hyperemia in patients who switched from timolol to latanoprost, but no change in those who continued latanoprost. The timolol-induced reduction of resting heart rate returned to baseline levels after switching to latanoprost. Of the 247 patients treated with latanoprost during the masked and/or open-label studies, 12 (5%) demonstrated a definite (n = 4) or possible (n = 8) increase in iris pigmentation.

CONCLUSIONS

Latanoprost is a well-tolerated ocular hypotensive agent that appears to be more effective than timolol in reducing intraocular pressure. The increase in iris pigmentation appears to be harmless but requires further investigation.

A proposed mechanism for p-aminoclonidine allergenicity based on its relative oxidative lability

p-Aminoclonidine (apraclonidine) is a selective alpha 2 adrenergic agonist used to reduce intraocular pressure in the treatment of glaucoma. Use of apraclonidine is frequently associated with severe local allergic effects which warrant discontinuation of the drug in affected patients. We have assessed the oxidative lability of apraclonidine relative to a panel of adrenergic agonists and/or known allergens; amodiaquine, epinephrine, clonidine, and brimonidine. These compounds were compared by their electrochemical potentials as well as their oxidative lability in the presence of several oxidative enzyme systems (i.e., horseradish peroxidase, lactoperoxidase, myeloperoxidase, and diamine oxidase). The half-lives for enzymatic oxidation of these compounds were found to parallel the electrochemical oxidation potentials in the order: amodiaquine approximately epinephrine < apraclonidine << clonidine approximately brimonidine. The production of a reactive electrophilic intermediate of apraclonidine was demonstrated through the formation of two glutathione apraclonidine adducts from the horseradish peroxidase/H2O2-mediated oxidation of apraclonidine in the presence of glutathione. A mechanism for apraclonidine allergenicity in vivo is proposed wherein apraclonidine is bioactivated through oxidation to the bis-iminoquinone followed by protein conjugation to form an apraclonidine-protein hapten that elicits the immune response.

Does medical treatment of mild intraocular hypertension prevent glaucoma?

Glaucoma is a serious disease that may cause a decrease in peripheral vision as well as blindness. Although the treatment of extreme levels of high intraocular pressure (p > 35 mm) reduces the risk of glaucoma it is not known if the treatment of mild and moderate intraocular pressure prevents the onset of glaucoma. A bibliographic search in Medline CD-ROM was performed from 1967 to 1995, as well as in SIGLE CD-ROM. The keywords used were 'glaucoma prevention' and 'glaucoma suspects'. After the search 18 papers which treated moderate and mild intraocular pressure were selected. Of all these papers, those that used the same methodology; randomization and timolol as treatment, were chosen. The possibility of publication bias was controlled by plotting effect size vs. number of papers, as well as effect size vs. year of publication. A meta-analysis using two methods, weighted zetas and adding zetas, was performed. The combined effect size was -6.25%, and the weighted effect size was -6.45%. We computed the pooled z by two methods: adding Zs and adding weighted Zs. The Z obtained by adding Zs has a value of 2.31120 p = 0.0177, one tail). Using the method of adding weighted Zs we obtained a value of 2.4201 (p = 0.0082, one tail). Our results show that the treatment with timolol of patients with mild and moderate intraocular pressure may help to prevent the onset of glaucoma.

Latanoprost, a prostaglandin analog, for glaucoma therapy. Efficacy and safety after 1 year of treatment in 198 patients. Latanoprost Study Groups

PURPOSE

To determine efficacy and safety of latanoprost, a prostaglandin analog for glaucoma, during 1 year of treatment.

METHODS

After baseline measurements, 0.005% latanoprost was topically applied once daily for 12 months in patients from Scandinavia, the United Kingdom, and the United States who had elevated intraocular pressure (IOP). Diagnoses included ocular hypertension, chronic open-angle glaucoma, exfoliation syndrome, and pigment dispersion syndrome. Treatment was masked for the first 6 months and open-label during the second 6 months.

RESULTS

Of the 272 patients initially enrolled, withdrawals were due to inadequate IOP control (1%), increased iris pigmentation (5%), other ocular problems (3%), systemic medical problems (3%), and nonmedical reasons (14%). Latanoprost significantly (P < 0.0001) reduced diumal IOP from 25.3 +/- 3.0 mmHg (mean +/- standard deviation) at baseline to 17.4 +/- 2.7 mmHg (32% reduction) at 12 months in the 198 patients who completed 1 year of treatment. The IOP reduction was maintained at a consistent level throughout the 12 months without evidence of drift, and was not affected by sex, age, race, or eye color. Overall, latanoprost caused a possible or definite increase in iris pigmentation in 12% of the 272 patients, all of whom had multicolored irides at baseline. One half of these patients with increased pigmentation withdrew before completing 1 year of therapy. Visual field, optic disc cupping, visual acuity, refractive error, conjunctival hyperemia, aqueous flare, anterior chamber cellular response, lens examination, blood pressure, heart rate, blood tests, and urinalysis were not appreciably altered.

CONCLUSION

Latanoprost safely and effectively reduces IOP for 1 year in patients of diverse nationalities, providing further evidence for its usefulness in chronic glaucoma therapy.

Contact allergy to ophthalmic dipivalyl epinephrine hydrochloride: demonstration by patch testing

A patient presented with a 3-month history of conjunctivitis and periocular eczema. He had a 3-year history of glaucoma and was being treated with 3 different locally applied eyedrops (Timoptic (timolol maleate) ophthalmic solution 0.25%, Pilocar (pilocarpine) ophthalmic solution 1%, and Propine (dipivalyl epinephrine hydrochloride) ophthalmic solution 0.1%). Patch testing with all 3 undiluted eyedrop solutions revealed a reaction only to Propine eyedrops. Patch testing to the individual components of Propine eyedrops revealed an allergic reaction to 0.5% dipivalyl epinephrine hydrochloride that was apparent on the 2nd patch test reading. After discontinuing the Propine eyedrops, the conjunctivitis as well as the periocular dermatitis resolved, proving that the positive patch tests were relevant to both. It was reported that re-exposure to dipivalyl epinephrine hydrochloride by intra-ocular challenge was necessary to diagnose this allergy. This is the first demonstration of dipivalyl epinephrine hydrochloride allergy by patch testing. Since the 1st patch test reading (2 days) was weak, 2nd patch test (4 days) readings may be important in diagnosing this allergy by patch testing.

Therapeutic index of epinephrine and dipivefrin with nasolacrimal occlusion

We assessed the effect of nasolacrimal occlusion on the therapeutic index of the adrenoreceptor agonists in healthy volunteers and patients with glaucoma. Nasolacrimal occlusion did not significantly alter the response to 2% epinephrine or to 0.1% dipivefrin in healthy subjects, suggesting that both 2% epinephrine and 0.1% dipivefrin are at the top of the dose-response curve. When 0.5% epinephrine with nasolacrimal occlusion was tested in patients with glaucoma, effects were noticeable at four and eight hours (P less than .05), but not at 12 hours. For 2% epinephrine, there was no significant difference at any measurement time. Epinephrine (1%) with and without nasolacrimal occlusion gave results similar to those of 2% epinephrine, suggesting that 1% epinephrine is also at the top of the dose-response curve. Nasolacrimal occlusion did not increase the ocular hypotensive effect of either of these concentrations. Because dipivefrin, the most widely used formulation in this class, is a prodrug of epinephrine that has a corneal penetration approximately 17 times that of epinephrine, 0.05% dipivefrin, every 12 hours, might be an adequate dosage for maximal effect. Although nasolacrimal occlusion did not alter the drug effect of 0.1% dipivefrin, preventing as much drug as possible from reaching the systemic circulation is desirable.

Visual impairment of open angle glaucomas at first presentation and after a five to ten year follow-up

Of all patients attended to in a clinic during 1986, 441 had open angle glaucoma diagnosed during 1974-1986 on the basis of either a verified visual field defect, a glaucomatous disc, or a repeated intraocular pressure value of at least 35 mm Hg. At first presentation of recent cases 1984-1986 (N = 128) 65 per cent were more than 70 years old. Capsular glaucomas were twice as common as simple glaucomas (low tension cases included). 62 per cent of capsular but only 26 per cent of simple glaucomas had an initial pressure of 35 mm Hg or more (p < 0.001). One third of both capsular and simple glaucomas had an advanced visual field defect with breakthrough to the periphery in the worse eye already at first presentation. This was more common if the initial pressure was 35 mm Hg or more (p < 0.05). Almost half remained unilateral cases, and the rate of severely impaired visual function in the better eye did not exceed 15 per cent. While generally 30-50 per cent of glaucomatous field defects had progressed in five years, the progression in early detected cases was only three per cent (p < 0.05). Visual field defects with breakthrough to the periphery already at first presentation progressed more often than circumscribed scotomas (p < 0.02).

Soluble forms of isobutylmethylxanthine enhance the ocular hypotension induced by catecholamines

Isobutylmethylxanthine (IBMX) suspended in 0.5% hydroxypropyl methylcellulose has been shown to enhance the reduction in intraocular pressure (IOP) induced by epinephrine and norepinephrine in rabbits and beagles. In the present study, the effects of two soluble forms of IBMX, i.e. the ethylenediamine salt (IBMX-ED) and IBMX bound to cyclodextrin in saline (IBMX-CD), were studied in rabbits. When used alone, 1% IBMX-ED did not affect the IOP, but the hypotensive response to 0.1% epinephrine was enhanced dose-dependently by combination of the catecholamine with IBMX-ED. Although 1% IBMX-CD applied alone also failed to influence the IOP, the hypotensive response to epinephrine, dipivalyl epinephrine and norepinephrine was enhanced by combination of these substances with IBMX-CD. Soluble IBMX-ED as well as soluble IBMX-CD and the IBMX suspension enhanced, to a similar extent and in a dose-dependent manner, the IOP reduction induced by catecholamines. IBMX-CD, which has a neutral pH, may be a suitable form of IBMX for future long-term experiments.

A comparison of treated and untreated glaucoma suspects

One hundred forty-three patients with intraocular pressures (IOPs) above 22 mmHg and without visual field defects or any obvious evidence of optic nerve damage were randomly assigned to either a timolol treatment group or no treatment in a 6-year prospective clinical trial. Endpoints were defined as reproducible visual field defects on automatic perimetry, disc hemorrhages, or stereophotographically documented optic nerve head changes. Endpoints developed in 42 patients: 28 visual field defects, 8 changes in disc appearance, and 6 disc hemorrhages. Of the 42 patients, 20 were treated and 22 were not. Survival analysis showed no statistically significant differences in failure time to any endpoints between the two groups. In the untreated group, the time to failure of disc change was related to the mean IOP during the study and also to the changes in the IOP from baseline. A significant correlation was found between initial cup-to-disc ratio and survival time to visual field defects in the untreated group.

Peripheral contrast sensitivity in glaucoma and ocular hypertension

Contrast sensitivity has been measured in patients with glaucoma and ocular hypertension, the latter graded into high, medium, and low risk clinical groups. Measurements were made centrally and peripherally at 10 degrees, 15 degrees, 20 degrees, and 25 degrees off-axis at each of the four meridians 45 degrees, 135 degrees, 225 degrees, and 315 degrees. A sine wave grating of 1.9 cycles/degree, reversing at 1 Hz was used. It was displayed on a 100-Hz refresh rate monitor. Normal values were established to compare those from 41 eyes from patients with either primary open angle glaucoma (POAG) with minimal field loss detectable on a Humphrey perimeter, or raised IOP and/or disc changes but no field loss (OH). Those with POAG had normal central contrast sensitivity, but at 20 degrees and 25 degrees eccentricity the values were greater than 2 standard deviations above the normal mean. This was also the case for high risk OH, but not for low risk patients. All the high risk patients except one who had abnormal peripheral contrast sensitivity had possible field defects (threshold elevation at one or more points more than 5 but less than 10 dB above normal mean). Only one of those with normal peripheral contrast sensitivity had such 'suspect points'. The results are assessed in terms of screening of glaucoma suspects.

Evaluation of ocular hypersensitivity to dipivalyl epinephrine by component eye-drop testing

Dipivalyl epinephrine (dipivefrin) is a prodrug of epinephrine used for topical glaucoma therapy. Local side effects have been noted in approximately 20% of patients treated and include conjunctival hyperemia, foreign body sensation, and follicular conjunctivitis. We studied five patients with adverse local reactions to dipivefrin (Propine) eye drops. Propine contains the following: dipivefrin, 0.1%; mannitol, 1.89%; sodium metabisulfite, 0.075%; disodium edetate, 0.0127%; and benzalkonium chloride, 0.004%. Since the reactions could conceivably have been caused by an ingredient other than dipivefrin, we first patch tested the patients with the maximum recommended concentration of each ingredient. All patch tests were negative. Sterile ophthalmic solutions of each individual component at the concentrations used in the commercial product were then prepared. In a double-blinded study, the patients applied two drops of each preparation, twice daily for 1 week, with a 1-week, drug-free period between trials. Dipivefrin alone reproduced each patient's initial Propine-induced conjunctivitis; symptoms occurred unilaterally in one patient and bilaterally in the other four patients. This study indicates that testing with single component eye drops can identify the provocative component in ocular drug hypersensitivity and that these reactions can be unilateral.

A long-term clinical trial of timolol therapy versus no treatment in the management of glaucoma suspects

One hundred seven patients with intraocular pressures (IOPs) between 22 and 28 mmHg with normal visual fields on Goldmann perimetry and without evidence of optic nerve damage were randomly assigned to either a timolol treatment (TT) or a no treatment (NT) arm in a prospective clinical trial. The patients were followed for an average of 56 and 51 months, respectively. Criteria for failure were a confirmed IOP of greater than 32 mmHg, stereophotographically documented optic nerve progression, or development of glaucomatous visual field loss by Goldmann or Octopus perimetry. Nine patients failed in the TT group and 17 in the NT group (P = 0.07). Of the nine TT group failures, six had discontinued timolol before failure (4 for greater than 6 months). In a Cox proportional hazards analysis controlling for confounding variables, timolol was found to be significantly protective with an adjusted risk ratio of 0.38 (95% confidence interval = 0.16-0.89, P = 0.03). When only field and disc failure criteria were considered, timolol treatment was found to be significantly protective in an analysis considering patients who stopped timolol as being lost to follow-up (P = 0.05). A higher tonographic facility of outflow was protective in all analyses. A trend toward a substantial loss of effectiveness of timolol on IOP was not observed. Seasonal fluctuations in IOP were observed (P = 0.0007), with higher IOP occurring in the winter. The results demonstrate a favorable influence of timolol therapy on the clinical course of patients with mildly elevated IOP.(ABSTRACT TRUNCATED AT 250 WORDS)

The benefit of early trabeculectomy versus conventional management in primary open angle glaucoma relative to severity of disease

One hundred and sixteen patients with newly diagnosed primary open angle glaucoma were selected for a randomised, prospective, multicentre trial if the untreated intraocular pressure was over 25 mmHg and there was field loss characteristic of glaucoma. Conventional management of medical therapy followed by trabeculectomy in unsuccessful cases was compared with trabeculectomy at diagnosis followed where necessary by supplementary medical therapy. At a mean follow-up of 4.6 years there was no significant difference in visual acuity between the groups but the conventional management group had significantly greater loss of visual field which occurred during the unsuccessful attempt at medical control. The eyes which lost most visual field were those with least field loss at diagnosis and this paradox was attributed to a prolonged attempt at medical control in these eyes because they were thought to have a lower risk of visual field deterioration.

Levobunolol compared with timolol: a four-year study

Fifty-one patients with raised intraocular pressure (IOP) were treated for up to four years with one of three ophthalmic solutions: 0.5% levobunolol, 1% levobunolol, or 0.5% timolol. The study was conducted as a double-masked, randomised trial in which medications were administered twice daily to both eyes. Levobunolol and timolol were equally effective in reducing overall mean IOP; reductions were greater than 8.8 mmHg in all three treatment groups. The study showed levobunolol to be as safe and effective as timolol in the long-term control of raised IOP.

A clinical trial of timolol and epinephrine in the treatment of primary open-angle glaucoma

Forty-seven patients with chronic open-angle glaucoma who required therapy but who had never been treated previously were enrolled in a prospective randomized, long-term clinical trial comparing the effectiveness of 0.5% timolol maleate and 1% epinephrine. Patients were followed for an average of 33 months. There were 20 failures, 18 of which were because of inadequate intraocular pressure (IOP) control (required 20% reduction in outflow pressure). Twelve failures were in the epinephrine group and eight were in the timolol group. During the first year of therapy, 35% compared with 0% of patients failed in the epinephrine and timolol groups, respectively (P less than 0.01). During the later years of the study, the failure rates in the two groups were similar. The results suggest that timolol is superior to epinephrine during the first year of therapy, and likely as effective as epinephrine in the long-term treatment of glaucoma.

Ophthalmic beta-blockers since timolol

In the twenty years since beta-blockers were proposed for treatment of glaucoma, use of topical timolol has increased to account for 70% of all glaucoma medications used. The objective of this article is to review the "newer" beta-blockers, and to address the generalization that "all ophthalmic beta-blockers are the same." The review concentrates on agents that have been studied as topical treatments for patients with elevated intraocular pressure. Sections on pharmacology and design of clinical trials are included to aid the ophthalmologist in evaluating the new drugs and published clinical reports. The major questions to consider in evaluating the therapeutic potential of a new beta-blocker for the treatment of glaucoma involve efficacy and safety: Is the drug as effective as timolol? Does it have a duration of action at least as long as timolol? Does it have ocular toxicity? Is it comfortable? What are its systemic effects?

Influence of exfoliation syndrome on prognosis in ocular hypertension greater than or equal to 25 mm. A long-term follow-up

Data on 144 patients who in 1969-1973 were found to have ocular hypertension greater than or equal to 25 mmHg without glaucomatous damage were collected retrospectively. Intraocular pressure-lowering treatment was prescribed with few exceptions. Thirteen out of 37 patients (35%) with exfoliation syndrome developed glaucomatous damage during the follow-up periods ranging from 5 to 14 years (mean 9.4 years). The corresponding result for patients without exfoliation syndrome was 20 out of 111 subjects (18%, mean follow-up 11.7 years, range 5-15 years). Low average intraocular pressure during the follow-up seemed to prevent the eyes from developing glaucomatous damage. This was especially evident for eyes with the exfoliation syndrome. The long-term effect of medical therapy on the pressure level of hypertensive eyes was often negligible.

Bulbar conjunctival follicles associated with dipivefrin therapy

Large bulbar conjunctival follicles developed in 12 patients who received dipivefrin therapy for prolonged periods in the management of chronic open-angle glaucoma. In four patients, the follicles encircled the limbus. Although several of the patients were taking other drugs, the follicles disappeared within one month of discontinuing only the dipivefrin therapy. Therapy was switched to epinephryl borate in some patients and to other forms of therapy in others, without incident. The clinical course, the Giemsa staining of conjunctival scrapings, the conjunctival biopsy, and the results of patch tests suggest that this is an irritant reaction to dipivefrin rather than a reaction to preservatives or an allergic reaction.

The value of screening for glaucoma with tonometry

This paper estimates the value of performing Schiotz tonometry to detect glaucoma in an asymptomatic patient. About 9% of adults over 40 will be found on a single Schiotz tonometry test to have elevated intraocular pressure (IOP). On work-up, about 1 out of 50 of these individuals with high IOP will be found to have glaucoma. Tonometry, however, will miss about half of all patients with glaucoma because they do not have elevated IOPs at the time of the test. Pilocarpine or epinephrine are the most commonly used drugs to treat the disease, but they are not always effective in lowering a patient's IOP or in stopping the progression of field defects. From the available evidence it does not appear that earlier diagnosis makes a substantial difference in the patient's outcome. If all individuals over 40 years of age in a city of 1,000,000 were screened, the total cost of finding and treating about 484 people with chronic simple glaucoma would be on the order of $4,944,866 or about $13,000 per patient potentially benefited. Screening with tonometry does not appear to be warranted.

Ocular effects of beta-adrenergic agents. XII Jules Stein Lecture

The ocular effects of beta-adrenergic agonists and antagonists are reviewed. The permeability of the rabbit corneal epithelium was estimated for various instilled drugs, and difference in pharmacokinetics of timolol between the albino and pigmented rabbit demonstrated. The effects of the drugs on the cornea and the lens epithelium, and also the distribution of the adrenergic receptors in the intraocular muscles were discussed. The beta-adrenergic receptors are present in the ciliary processes of the rabbit as shown through studies by biochemical pharmacology and cytochemical electron microscopy. Adrenergic effects on the blood flow and the vascular permeability of the anterior uvea were discussed. The effects of adrenergic drugs on aqueous humor dynamics differ considerably among rabbits, monkey and the human subjects, and they were discussed separately for these species. The mechanism underlying the hypotensive effects of beta-adrenergic drugs is complex, but the available data indicate that in the human eye the hypotensive effects of epinephrine are attributed mainly to a decrease in the outflow resistance and the effects of timolol are principally to a reduction of aqueous humor formation.

Cardiovascular effects of epinephrine and dipivalyl epinephrine applied topically to the eye in patients with glaucoma

The cardiovascular effects of topical ophthalmological preparations of 2% epinephrine (EPI), 0.1% dipivalyl epinephrine (DPE), and placebo were studied in double-blind fashion in 20 patients with glaucoma. Both drugs and placebo produced a decrease in heart rate (2 +/- 3 beats/min) which, although small, was highly significant (p less than 0.001). Neither drug not placebo produced a significant effect on mean or systolic blood pressure (BP) over the group as a whole (p greater than 0.1). However, 5 of 20 patients responded to EPI with a significant rise in mean or systolic BP (defined as a change greater than mean change +/- 2 SD), whereas there were no such responses to DPE or placebo. One patient developed marked ventricular ectopy after EPI. We conclude that EPI may cause cardiovascular side effects in a high percentage of patients (25% in this study) through individual susceptibility rather than a predictable effect. DPE, a new epinephrine analogue, appears to be devoid of these effects.

Toxicity of dipivalyl epinephrine

Fourteen patients with open-angle glaucoma applied one drop 0.1% dipivalyl epinephrine topically twice daily for three years. Four of the 14 patients developed severe blepharoconjunctivitis after 17 to 26 months of exposure to this epinephrine prodrug. Two of the four patients with dipivalyl epinephrine intolerance had a history of epinephrine intolerance. Three other patients had asymptomatic conjunctival hyperemia after 30 months of dipivalyl epinephrine exposure. No patients had conjunctival pigment deposits or cardiovascular side effects. The exfoliative cytology of two patients was characterized by karyomegaly of the conjunctival epithelial cells.

Epinephrine as the initial therapy in selected cases of ocular hypertension

The authors believe that the epinephrines should be employed as the initial therapy in both primary open angle glaucoma and, when treated, ocular hypertension. Unlike pilocarpine, epinephrine does not produce miosis and accommodative spasm. Because of longer experience with epinephrine than with costly timolol, its longterm effectiveness and side effects are better known. Although the side effects of epinephrine are usually not serious, they may be intolerable to the patient. However, allergic blepharoconjunctivitis may be ameliorated by concomitant hydroxymesterone therapy. The availability of dipivalyl epinephrine (DPE) may decidedly shift the balance of the treatment of ocular hypertension, when indicated, to an epinephrine compound.

Acute angle-closure glaucoma secondary to an aneurysm of the posterior communicating artery

A 57-year-old woman developed pain behind and above her left eye. She had a partial oculomotor nerve paresis manifest by slight blepharoptosis and a dilated pupil. Both anterior chamber angles were narrow but the left was partially occluded. There was no photophobia or corneal edema. Though the moderately increased intraocular pressure was controlled by medication, pain persisted and the oculomotor nerve palsy became complete 12 hours later. Cerebral angiography was done. She had an aneurysm of the left posterior communicating artery. The aneurysm was treated by neurosurgical techniques and the oculomotor paralysis resolved within a few months except for misdirection in regeneration.

Dipivefrin: current concepts

Pro-drugs are agents that require biotransformation prior to exhibiting pharmacologic activity. Dipivefrin (dipivalyl epinephrine or DPE) is an epinephrine pro-drug produced by the addition of two pivalic acid groups to the parent compound. This creates a more lipophilic molecule which penetrates the cornea more readily than epinephrine. Enzymes in ocular tissues convert dipivefrin into its active form, epinephrine. In concentrations approximately one-tenth that of epinephrine, topically applied dipivefrin therefore produces: (1) similar intra-ocular concentrations of epinephrine; (2) similar reductions in intra-ocular pressure (IOP); (3) similar degrees of mydriasis; and (4) fewer extraocular and systemic side effects. For reasons that are discussed, dipivefrin should probably not be used in conjunction with anticholinesterases. Dipivefrin offers the same risk of cystoid macular oedema as does epinephrine. Dipivefrin is a safe, effective, and well-tolerated alternative to epinephrine in the treatment of elevated IOP. It is particularly useful for patients who cannot tolerate epinephrine.

The optic disc in glaucoma. IV: Optic disc evaluation in the ocular hypertensive patient

A prospective study was carried out over a 3-year period on patients with one normotensive eye and one eye with ocular hypertension. A greater variability inthe responses to visual field testing was apparent in the hypertensive eye, but only on comparison of serial visual fields. Analysis of the stereo disc photographs demonstrated larger cup to disc ratios in the hypertensive eye without changes in the nerve fibre layer to equate with the visual field response. Stero disc photography is a quick and simple method of recording changes in the optic disc and should be considered in the follow-up of ocular hypertensive patients.

External ocular toxicity of dipivalyl epinephrine

Of 26 patients enrolled in a study designed to assess the usefulness of dipivalyl epinephrine 0.1%, administered topically at 12-hour intervals, for lowering intraocular pressure in patients with glaucoma and ocular hypertension, six patients (23.1%) developed adverse external ocular side effects severe enough to require that the drug be discontinued. Four of these six patients had a history of previous intolerance to epinephrine. The other two had successfully used epinephrine HCl 2% for more than two years before being treated with dipivalyl epinephrine and developed an adverse reaction after taking the drug 18 and 22 months, respectively. One patient with a history of epinephrine intolerance has successfully used dipivalyl epinephrine for 26 months to date. Our observations suggest that duration of exposure is an important factor in the development of sensitization to topically applied dipivalyl epinephrine.

Patient compliance and the "usefulness product" of timolol

The practical value of any therapy depends upon a combination of effectiveness of the agent (or procedure) and the extent to which the patient complies in its proper administration. Thus, it might be said that the multiple of effectiveness times compliance equals the "usefulness product." Among the various glaucoma therapies, this product seems to range from about 30%--90%. Timolol's effectiveness in lowering intraocular pressure combined with its low incidence of side effects yields a high usefulness product, and this may decrease the incidence of surgery required for the treatment of the open-angle glaucomas.

Allergic contact dermatits and conjunctivitis from epinephrine

A patient with chronic open-angle glaucoma was suspected of having allergic dermatitis and conjunctivitis to epinephrine. He was tested with epinephrine and other active substances, the preservatives and antioxidants usually used in the preparation of eye drops. He was also tested with other possible contactants with which he had had contact. The patient showed positive allergic patch test reactions to the chloride solution of epinephrine. The patient showed an unexpected positive reaction when tested with di-isopropyl fluorophosphate (DFP). The importance of routine patch testing in ophthalmic practice to detect sensitizers in cases of contact allergy is stressed.

The effects of dipivalyl epinephrine on the eye

We treated one eye each of ten patients with ocular hypertension with dipivalyl epinephrine (DPE), a congener of epinephrine. Pupil size and intraocular pressure were measured before and at intervals up to 240 minutes after instillation of a single drop of DPE in concentrations from 0.005 to 0.5%. Concentrations of 0.025% DPE and greater significantly reduced IOP, and mydriasis was induced by concentrations of 0.1% DPE or greater. Comcentrations of 0.1% DPE, instilled twice daily for one month, significantly reduced intraocular pressure during diurnal testing on days 2 and 31. No toxic side effects were noted. The DPE produced dose-related increases of cyclic adenosine monophosphate in the aqueous humor of rabbits.