Latanoprost and cystoid macular edema: is there a causal relation?

The Impact of Systemic Medications on Retinal Function

This study will provide a thorough review of systemic (and select intravitreal) medications, along with illicit drugs that are capable of causing various patterns of retinal toxicity. The diagnosis is established by taking a thorough medication and drug history, and then by pattern recognition of the clinical retinal changes and multimodal imaging features. Examples of all of these types of toxicity will be thoroughly reviewed, including agents that cause retinal pigment epithelial disruption (hydroxychloroquine, thioridazine, pentosan polysulfate sodium, dideoxyinosine), retinal vascular occlusion (quinine, oral contraceptives), cystoid macular edema/retinal edema (nicotinic acid, sulfa-containing medications, taxels, glitazones), crystalline deposition (tamoxifen, canthaxanthin, methoxyflurane), uveitis, miscellaneous, and subjective visual symptoms (digoxin, sildenafil). The impact of newer chemotherapeutics and immunotherapeutics (tyrosine kinase inhibitor, mitogen-activated protein kinase kinase, checkpoint, anaplastic lymphoma kinase, extracellular signal-regulated kinase inhibitors, and others), will also be thoroughly reviewed. The mechanism of action will be explored in detail when known. When applicable, preventive measures will be discussed, and treatment will be reviewed. Illicit drugs (cannabinoids, cocaine, heroin, methamphetamine, alkyl nitrite), will also be reviewed in terms of the potential impact on retinal function.

Medical therapy for glaucoma: A review

A number of pharmacological targets are exploited to modify the parameters in the Goldmann equation and reduce the intraocular pressure (IOP). This strategy constitutes the foundation for the medical management of glaucoma, the evolution of which, until only recently, has been in relative stagnation. A burst of innovation has produced new ocular hypotensive drugs and long-acting delivery methods, including intracameral delivery, which are expanding the clinician's medical armamentarium. A number of IOP-independent neuroprotection strategies have shown strong potential in animal models of glaucoma, but translational attempts have been surprisingly limited. However, while pharmacological options are expanding, the traditional role of topical medical therapy is being challenged by selective laser trabeculoplasty, micro-invasive glaucoma surgery, and sustained delivery methods. A scientifically rigorous assessment of new treatments will be critical to empower clinicians with evidence-based information to optimise vision preservation and quality of life outcomes for their patients.

[Frequency and type of macular edema after cataract surgery in patients with glaucoma]

Cataract is one of the common causes of reversible vision loss in people older than 50 years. Currently, the only way to treat it effectively is phacoemulsification with simultaneous implantation of an intraocular lens - a method that minimizes the amount of surgical trauma and the number of intra- and postoperative complications. Nevertheless, the problem of prevention and timely diagnosis of pathological changes in the retina, which may develop after extraction of cataracts, and in particular - macular edema, remains relevant. This problem becomes especially important when it comes to patients with concomitant cataract and glaucoma who use local antihypertensive drugs - in particular, prostaglandin analogues - for a long time. Having common properties with inflammatory mediators, in some cases they can cause vasodilation, increase vascular permeability and contribute to the development of exudative processes. Drugs of this group can cause impairment of the hematophthalmic and hematoretinal barriers provoking the development of cystoid macular edema, including in the early postoperative period after cataract extraction. As described by S. Irvine in 1953, macular edema is related to late postoperative complications and remains one of the main causes of visual impairment after lens removal. The review provides information about some studies concerning the effect of prostaglandin derivatives on the postoperative period after phacoemulsification. At this time, there is no consensus on this matter.

Association of Postoperative Topical Prostaglandin Analog or Beta-Blocker Use and Incidence of Pseudophakic Cystoid Macular Edema

PURPOSE

The purpose of this article is to determine the association of postoperative topical prostaglandin analog (PGA) or topical beta-blocker use and the incidence of pseudophakic cystoid macular edema (CME).

METHODS

This was a nested case-control study. All adult patients who underwent cataract surgery between January 1, 2006 and December 31, 2016 and who were enrolled in the PharMetrics Plus database were eligible for inclusion. The association between postoperative topical PGAs (bimatoprost, latanoprost, and travoprost/travoprost-z) or beta-blocker (betaxolol, levobunolol, and timolol) use and the incidence of pseudophakic CME was assessed by conditional logistic regression.

RESULTS

Five hundred eight cases and 5080 controls were included in the analyses. Incidence of pseudophakic CME was found to be statistically significantly associated with the current postoperative use of both topical PGAs [relative risk (RR), 1.86; 95% confidence interval (CI), 1.04-3.32] and topical beta-blockers (RR, 2.64; 95% CI, 1.08-6.49). Postoperative use of each of bimatoprost (RR, 2.73; 95% CI, 1.35%-5.53%) and travoprost/travoprost-z (RR, 3.16; 95% CI, 1.42-7.03) in the year before diagnosis was demonstrated to be statistically significantly associated with the incidence of pseudophakic CME. This association was not observed to be statistically significant with the postoperative use of latanoprost (RR, 1.55; 95% CI, 0.84-2.88).

CONCLUSIONS

To the best of our knowledge this is the largest study that has investigated the association between postoperative topical PGA or topical beta-blocker use and the incidence of pseudophakic CME. Postoperative use of both topical PGAs and topical beta-blockers was found to be associated with the incidence of pseudophakic CME.

The Effect of Latanaprost on Intraocular Inflammation and Macular Edema

There is debate concerning whether the use of Latanoprost in early postoperative period of cataract surgery and in glaucoma patients with uveitis as it may aggravate the inflammation and results in macular edema (ME), because of blood-ocular barrier disruption. However, there is no solid evidence for disruption of blood-ocular barrier with Latanoprost and aggravation of uveitis or ME formation. Similar to pseudophakic ME, the imaging ME in cases claimed to be secondary to Latanoprost is greater than clinical ME, happens mostly in complicated surgeries, and the vast majority resolve within weeks to months with using a non-steroidal anti-inflammatory drug. The current literature suggests that Latanoprost can be used in patients with uveitis and early after cataract surgery with or without concomitant topical non-steroidal anti-inflammatory drugs that are currently used by many ophthalmologists as a preventive measure for ME even in non-glaucoma uncomplicated cataract surgeries.

Patient considerations in ocular hypertension: role of bimatoprost ophthalmic solution

Glaucoma is a leading cause of irreversible blindness worldwide. The reduction of intraocular pressure has been well established as an effective treatment to prevent both the development and the progression of all forms of glaucoma. Bimatoprost 0.03% ophthalmic solution, introduced in 2001, is a synthetic prostamide with the unique mechanism of improving both uveoscleral and trabecular outflow. Comparative studies with other pharmacotherapies have shown favorable results for bimatoprost as a potent ocular hypotensive agent that is generally well tolerated. Common side effects include conjunctival hyperemia, eyelash growth, iris pigmentation and periorbital changes. Hyperemia rates were reduced following the introduction of bimatoprost 0.01%. Bimatoprost should be used with caution in those with higher risk of developing ocular inflammation and macular edema. However, the perceived risk of bimatoprost in these patient populations is likely greater than the actual risk observed in practice. Bimatoprost is currently in the center of several clinical trials including its use for dermatologic applications and sustained-release therapies for the treatment of ocular hypertension and glaucoma.

Pharmacotherapy and Adherence Issues in Treating Elderly Patients with Glaucoma

Glaucoma is a leading cause of visual morbidity throughout the world and is an age-related condition, the prevalence of which rises significantly with increasing age. Glaucoma, a condition affecting the optic nerve, has a variety of subtypes with multiple aetiological factors, the most important of which are intraocular pressure (IOP) and increasing age. Treatment by lowering of IOP is the only current method, for which there is evidence, by which the rate of progressive visual deterioration can be slowed or halted. Although there are surgical and laser treatments that are efficacious in lowering IOP, the most common manner in which patients with glaucoma control their IOP is with administration of daily topical ocular hypotensive drugs (eye drops). The variety of topical drugs utilised in the management of glaucoma all have the potential to have adverse effects and/or interactions with concomitant medications, many of which may be used for other age-related conditions. Adherence with appropriate medicines has a major effect on the outcome of medical conditions and this aspect applies to the management of glaucoma. There are certain specific issues that relate to the administration of topical agents, with respect to both adverse effects and adherence. Although many suspect poor adherence in elderly patients with glaucoma, relative to younger patients, adequate evidence for this is lacking. Furthermore, the manner by which adherence issues could be improved remains inadequately understood and poorly addressed. The aims of this article were to review, from a clinical perspective, the medical therapies currently used for glaucoma and discuss adherence issues with respect to the population of patients with glaucoma, who tend to be relatively elderly.

[General substance classification and pharmacology of glaucoma]

The pharmaceutical therapy of glaucoma dates back to 1875 when Weber introduced pilocarpine into the medicinal treatment of glaucoma. Since then there has been a continuous development of topical antiglaucoma therapy whereby the main developments date back to the 1980s and 1990s. All forms of medicinal therapy aim at lowering the intraocular pressure and achieve this either by inhibiting aqueous humor secretion into the ciliary body or by enhancing physiological drainage routes along Schlemm's canal. This article gives an overview over the most important classes of antiglaucoma drugs, the indications and contraindications as well as pharmacological characteristics. The focus lies on the market of combination and generic drug preparations that is currently rapidly developing and therefore needs to be discussed in detail.

Perioperative pharmacological management in patients with glaucoma

REVIEẂS AIM: When a phacoemulsification, a filtration surgery or a combined surgery are necessary, questions about the convenience of continuing certain antiglaucomatous drugs could appear. The aim of this review article is to unify criteria that will guide daily clinical practice and including the developing algorithms of action in the preoperative and postoperative periods of filtration surgery and/or cataract surgery.

PROPOSED PROTOCOLS

In the preoperative period of cataract surgery, the use of non-steroidal anti-inflammatory drugs is at the discretion of the surgeon, with the monodose presentation being recommended. The suspension of prostaglandines a fewdays before the surgery should be considered. Preservative-free drugs ensure a better recovery of the ocular surface (OS) after cataract surgery. Once all modifying factors of the intraocular pressure (IOP) have been removed, baseline IOP should be evaluated again, choosing preservative-free antiglaucomatous drugs when needed. The use of preservative-free ocular antihypertensive drugs and steroids in the preoperative period of glaucoma surgery reduces the risk of surgical failure. The interruption of prostaglandines is recommended. In the postoperative period of glaucoma surgery, steroids are the anti-inflammatory treatment of choice, the preservative-free ones being preferred. When reintroducing antiglaucomatous treatment, preservatives should be avoided to prevent scarring. The appropriate perioperative management of patients with glaucoma is essential to obtain a correct control of IOP, improve the situation of the OS, prevent complications and improve the result of the filtration surgery and cataract surgery.

CONCLUSIONS

this protocol aims to unify the different lines of action in order to decrease the incidence of adverse events and maximize the surgical outcome.

Sustained drug release in nanomedicine: a long-acting nanocarrier-based formulation for glaucoma

Therapeutic nanomedicine has concentrated mostly on anticancer therapy by making use of the nanosize for targeted therapy. Such nanocarriers are not expected to have sustained release of the bioactive molecule beyond a few days. There are other conditions where patients can benefit from sustained duration of action following a single instillation, but achieving this has been difficult in nanosized carriers. An important prerequisite for sustained delivery over several months is to have sufficiently high drug loading, without disruption or changes to the shape of the nanocarriers. Here we report on successful development of a drug-encapsulated nanocarrier for reducing intraocular pressure in a diseased nonhuman primate model and explain why it has been possible to achieve sustained action in vivo. The drug is a prostaglandin derivative, latanoprost, while the carrier is a nanosized unilamellar vesicle. The mechanistic details of this unique drug-nanocarrier combination were elucidated by isothermal titration calorimetry. We show, using Cryo-TEM and dynamic light scattering, that the spherical shape of the liposomes is conserved even at the highest loading of latanoprost and that specific molecular interactions between the drug and the lipid are the reasons behind improved stability and sustained release. The in vivo results clearly attest to sustained efficacy of lowering the intraocular pressure for 120 days, making this an excellent candidate to be the first truly sustained-release nanomedicine product. The mechanistic details we have uncovered should enable development of similar systems for other conditions where sustained release from nanocarriers is desired.

A review of the use of latanoprost for glaucoma since its launch

INTRODUCTION

Prostaglandins are increasingly used as first choice treatment for glaucoma because they are highly effective, lack relevant systemic side effects and require just once-daily administration. Latanoprost is an ester prodrug analog of prostaglandin F2α, which reduces intraocular pressure (IOP) by increasing uveoscleral outflow. Latanoprost 0.005% has received European and US approval as the first-line drug for reducing IOP in patients with open-angle glaucoma or ocular hypertension. Following the recent patent expiry for Xalatan®, a number of latanoprost generics have entered the glaucoma market.

AREAS COVERED

This review, achieved through PubMed and Medline research methods, describes the composition, pharmacokinetics, mode of action, efficacy, side effects and safety profile of latanoprost.

EXPERT OPINION

Latanoprost was the first prostaglandin analog introduced in glaucoma management and it dramatically changed the market of the disease thanks to its efficacy and safety. Conjunctival hyperemia, which is commonly found after latanoprost use, is associated with a minor efficacy and duration of trabeculectomy; yet, from the ophthalmologist's perspective, this side effect seems largely counterbalanced by the high efficacy and safety of this compound. It is always advisable to consider the pro-inflammatory mode of action of latanoprost because this may have negative effects in particular patients (i.e., those with uveitis and cystoid macular edema) for whom caution and close follow-up is necessary.

The use of prostaglandin analogs in the uveitic patient

Glaucoma is a disease process characterized by progressive optic nerve damage and corresponding visual field loss. It may be further categorized into either primary open-angle glaucoma or secondary glaucoma. These secondary glaucomas include glaucomas associated with uveitis and inflammation. Prostaglandin analogs (PGA) have been used to help lower intraocular pressure (IOP) in these often difficult to manage eyes. However, controversy exists concerning their use in uveitic patients due to the theoretically higher risk of anterior uveitis, development of cystoid macular edema (CME), and reactivation of herpes simplex keratitis (HSK). There is little evidence that PGA disrupt the blood-aqueous barrier and only anecdotal evidence suggesting an increased risk of these rare findings. PGA may be used in uveitic glaucoma when other topical treatments have not lowered IOP to the patient's target range.

The management of complicated glaucoma

Complicated glaucomas present considerable diagnostic and management challenges. Response to treatment can be unpredictable or reduced compared with other glaucomas. However, target intraocular pressure and preservation of vision may be achieved with selected medical, laser and surgical treatment. The evidence for such treatment is expanding and consequently affords clinicians a better understanding of established and novel techniques. Herein we review the mechanisms involved in the development of complicated glaucoma and the current evidence supporting its management.

Macular edema: miscellaneous

This article provides the reader with practical information to be applied to the various remaining causes of macular edema. Some macular edemas linked to ocular diseases like radiotherapy after ocular melanomas remained of poor functional prognosis due to the primary disease. On the contrary, macular edemas occurring after retinal detachment or after some systemic or local treatment use are often temporary. Macular edema associated with epiretinal membranes or vitreomacular traction is the main cause of poor functional recovery. However, the delay to observe a significant improvement of vision after surgery should be long, as usually observed in tractional myopic vitreoschisis. Finally, some circumstances of macular edemas such as hemangiomas or macroaneurysms should be treated, if symptomatic, with the treatments currently used in diabetic macular edema or exudative macular degeneration.

Clinical utility and differential effects of prostaglandin analogs in the management of raised intraocular pressure and ocular hypertension

Prostaglandin analogs (PGA) are powerful topical ocular hypotensive agents available for the treatment of elevated intraocular pressure (IOP). Latanoprost 0.005% and travoprost 0.004% are prodrugs and analogs of prostaglandin F2α. Bimatoprost 0.03% is regarded as a prostamide, and debate continues as to whether it is a prodrug. The free acids of all 3 PGAs reduce IOP by enhancing uveoscleral and trabecular outflow via direct effects on ciliary muscle relaxation and remodeling of extracellular matrix. The vast majority of clinical trials demonstrate IOP-lowering superiority of latanoprost, bimatoprost and travoprost compared with timolol 0.5%, brimonidine 0.2%, or dorzolamide 2% monotherapy. Bimatoprost appears to be more efficacious in IOP-lowering compared with latanoprost, with weighted mean difference in IOP reduction documented in one meta-analysis of 2.59% to 5.60% from 1- to 6-months study duration. PGAs reduce IOP further when used as adjunctive therapy. Fixed combinations of latanoprost, bimatoprost or travoprost formulated with timolol 0.5% and administered once daily are superior to monotherapy of its constituent parts. PGA have near absence of systemic side effects, although do have other commonly encountered ocular adverse effects. The adverse effects of PGA, and also those found more frequently with bimatoprost use include ocular hyperemia, eyelash growth, and peri-ocular pigmentary changes. Iris pigmentary change is unique to PGA treatment. Once daily administration and near absence of systemic side effects enhances tolerance and compliance. PGAs are often prescribed as first-line treatment for ocular hypertension and open-angle glaucoma.

Clinical cystoid macular edema after cataract surgery in glaucoma patients

PURPOSE

To determine the prevalence of and risk factors for developing clinical cystoid macular edema (CME) after cataract surgery in patients with glaucoma.

PATIENTS AND METHODS

Medical records of patients who had cataract surgery between April 1998 and July 2006 without prior history of CME, a known risk factor to develop CME, or previous nonglaucoma ocular laser procedures or intraocular surgeries were reviewed. Clinical CME was diagnosed by fundus examination within 3 months postoperatively and confirmed with fluorescein angiography or optical coherence tomography. Outcome measures included prevalence of clinical CME by comparing patients with and without glaucoma; and risk factor analysis for clinical CME by comparing patients who did and did not develop CME after cataract surgery.

RESULTS

Seven hundred patients (eyes) with glaucoma and 553 patients (eyes) without glaucoma were included. The prevalences of clinical CME in glaucoma and nonglaucoma patients were 5.14% and 5.79%, respectively (P=0.618). Patients who developed clinical CME (68 patients) had statistically higher rates of posterior capsule rupture or required anterior vitrectomy during surgery (P=0.010, odds ratio=3.35, 95% CI 1.33-8.45) compared with patients who did not develop clinical CME (1185 patients). No glaucoma medications used either preoperatively or postoperatively were associated with clinical CME (P>0.05).

CONCLUSIONS

Rupture of posterior capsule and anterior vitrectomy during cataract surgery is a potential risk factor for developing clinical CME after cataract surgery. There is no statistically significant difference in the prevalence of clinical CME after small corneal incision phacoemulsification cataract surgery between glaucoma and nonglaucoma patients.

Latanoprost-Dependent Cystoid Macular Edema Following Uncomplicated Cataract Surgery in Pseudoexfoliative Eyes

Cystoid macular edema (CME) following uncomplicated phacoemulcification associated with latanoprost is uncommon. OCT-proven CME associated with latanoprost in 3 eyes with pseudoexfoliation after uncomplicated phacoemulcification was reported. Latanoprost was discontinued whereas topical ketorolac was administered. In all cases, CME resolved completely within the following weeks. In one case the re-administration of latanoprost lead to CME recurrence, which was treated with permanent discontinuation of latanoprost. The correlation between latanoprost and CME and the complete resolution of CME following discontinuation of the drug suggest a causative association between latanoprost and CME.

Side effects associated with prostaglandin analog therapy

Topical prostaglandin analogs, which have become first-line therapy in the medical management of glaucoma, have an excellent safety profile with regard to systemic side effects, but are associated with several ocular side effects. Some of these are common, with no apparent serious consequences other than cosmetic, whereas others are much less common but represent potentially sight-threatening side effects. The former group includes conjunctival hyperemia, elongation and darkening of eyelashes, induced iris darkening, and periocular skin pigmentation. The latter group of side effects, which are relatively rare and lack definitive causal relationship to prostaglandin analog therapy, includes iris cysts, cystoid macular edema, anterior uveitis, and reactivation of herpes simplex keratitis. Most of the literature regarding side effects associated with prostaglandin analogs involves the use of latanoprost, probably because it was the first to be studied. There is no evidence, however, aside from less conjunctival hyperemia with latanoprost, that the commercially available prostaglandin analogs differ significantly with regard to side effects.

Influence of topical bimatoprost on macular thickness and volume in glaucoma patients with phakic eyes

BACKGROUND

In light of concern about the possible relation between the extensive clinical use of prostaglandin analogues and the development of retinal disorders such as cystoid macular edema, this study investigated the influence of topical application of bimatoprost 0.03% on macular thickness and volume in glaucoma patients with phakic eyes.

METHODS

A total of 40 eyes in 22 patients with primary open-angle glaucoma or normal-tension glaucoma were evaluated in this study. Optical coherence tomography images were taken before initiation of bimatoprost application and after 1, 2, and 3 months of treatment. In addition, best-corrected visual acuity (BCVA) and intraocular pressure (IOP) were measured, and contrast sensitivity tests and fundus examinations were performed. Changes in various parameters, including macular thickness and volume, were analyzed.

RESULTS

BCVA and contrast sensitivity did not change from baseline over the treatment period. IOP declined by 20% to 25% from baseline for 1 month before stabilizing. Macular thickness and volume did not increase significantly during the 3 months.

INTERPRETATION

Topical application of bimatoprost does not induce clinical or structural changes in the macula, at least in glaucoma patients with phakic eyes. Moreover, bimatoprost effectively lowered IOP without causing macular disorders such as cystoid macular edema.

Efficacité du latanoprost, donné en première ou deuxième intention, sur la pression intra-oculaire et la symptomatologie oculaire chez des patients présentant un glaucome à angle ouvert ou une hypertension oculaire simple

OBJECTIVES

The aim of this study was to assess the changes in intraocular pressure (IOP) and ophthalmic symptoms with the Glaucoma Symptom Scale in patients suffering from open-angle glaucoma (OAG) or ocular hypertension (OHT) after 3 months of treatment with latanoprost.

MATERIALS AND METHODS

This multicentric open study was carried out in adult patients suffering from OAG or simple OHT (naive or previously treated with monotherapy) and needing a change or initiation of anti-glaucomatous treatment. One drop of latanoprost 0.005% was instilled every evening for 12 weeks in each affected eye. Efficacy was assessed by the variation in IOP and ophthalmic symptomatology at the end of treatment. Prognosis factors associated with a relative IOP reduction of at least 30% were sought (using a logistic regression model).

RESULTS

A total of 920 patients suffering from OAG (54%) or OHT (44%), either previously treated (69%) or naive (31%), were included. The male:female ratio was 0.78 and the mean age was 63+/-13 years. At inclusion, the mean IOP was 22.1+/-3.8 mmHg. After treatment, IOP was significantly decreased by 5.1+/-4 mmHg, corresponding to a 22% reduction. IOP reduction was 7.1+/-4 mmHg, corresponding to 29% in naive patients and 4.2+/-4 mmHg, corresponding to 19% in previously treated patients. A relative IOP reduction of at least 30% was reached by 47% of naive patients and 21% of previously treated patients. In previously treated patients, a relative IOP reduction of at least 30% had a greater chance of being reached in men with previous ophthalmic history and high IOP at inclusion (above 21 mmHg). IOP reduction was similar in patients with OAG and OHT. A significant improvement in ophthalmic symptoms was observed after treatment in previously treated patients. A total of 7% of the patients presented an adverse event affecting the visual system: eye irritation (2%), eye pain (2%), or eye hyperemia (1%). Compliance was good for 94% of the patients.

CONCLUSION

Latanoprost given as first or second-line treatment at the recommended dose effectively decreases IOP in patients with OAG or OHT. This treatment also improves visual and nonvisual symptoms in previously treated patients and presents a good safety profile.

Latanoprost : an update of its use in glaucoma and ocular hypertension

Latanoprost (Xalatan) is an ester analogue of prostaglandin F2alpha that reduces intraocular pressure (IOP) by increasing uveoscleral outflow. The IOP-lowering efficacy of latanoprost 0.005% lasts for up to 24 hours after a single topical dose, which allows for a once-daily dosage regimen. In patients with ocular hypertension or open-angle glaucoma, a single drop of latanoprost 0.005% solution (about 1.5 microg) administered topically once daily reduced diurnal IOP by 22 to 39% over 1 to 12 months' treatment in well-controlled trials; efficacy was maintained during treatment periods of up to 2 years. At this dosage, latanoprost was significantly more effective than timolol 0.5% twice daily in 3 of 4 large, double-blind, randomised studies, was generally as effective as bimatoprost or travoprost, and was significantly more effective than dorzolamide, brimonidine or unoprostone. Furthermore, in patients whose IOP was poorly controlled with timolol, switching to latanoprost monotherapy was at least as effective at lowering IOP as adding dorzolamide or pilocarpine to the regimen. Latanoprost has also shown significant additive effects when used in combination with one or more other glaucoma medications. The fixed combination of latanoprost plus timolol was significantly more effective than either of its individual components in two double-blind randomised studies and more effective than the fixed combination of dorzolamide and timolol in a 3-month, evaluator-masked study. Data in patients with angle-closure glaucoma are limited, but in patients with elevated IOP after undergoing iridotomy, latanoprost 0.005% once daily was significantly more effective than timolol 0.5% twice daily at reducing IOP over 12 weeks of treatment in a large double-blind, randomised study. Latanoprost is generally well tolerated and, unlike timolol, induces minimal systemic adverse events. In well-controlled, 6-month trials, the most commonly occurring drug-related ocular events in latanoprost recipients were mild to moderate conjunctival hyperaemia (3 to 15%) and iris colour change (2 to 9%); these seldom required patient withdrawal although the latter may be permanent. Latanoprost 0.005% as a single daily drop has shown good IOP-lowering efficacy in patients with open-angle glaucoma or ocular hypertension and does not produce the cardiopulmonary adverse effects associated with beta-blockers. Thus, latanoprost is a valuable addition to the first-line treatment options for patients with open-angle glaucoma or ocular hypertension. In addition, adjunctive treatment with latanoprost in patients who are refractory to beta-blocker therapy is a viable, second-line treatment option. Although preliminary findings are promising, wider clinical experience is required to define the place of latanoprost in the treatment of angle-closure glaucoma.

Effects of latanoprost on blood-retinal barrier permeability in rabbits

PURPOSE

To investigate the effect of latanoprost (LP) on the inward and outward permeability (Pin and Pout) of the blood-retinal barrier (BRB).

METHODS

Four New Zealand white rabbits received topical LP (0.005%) once daily for 3 weeks in one eye and phosphate-buffered saline (PBS) in the fellow eye (topical group). Five New Zealand white rabbits were injected intravitreously with LP (0.1 ml, 0.005%) in one eye and PBS (0.1 ml) in the fellow eye (injection group). In the injection group, vitreous fluorophotometry (VFP) to estimate the Pin and differential vitreous fluorophotometry (DVF) to estimate the Pout were performed 60 min after LP was injected. After the baseline measurements, VFP and DVF were performed 60 and 180 min after intravenous injection of sodium fluorescein, respectively. Fluorescein (F) and fluorescein monoglucuronide (FG) concentrations were obtained by DVF, and the F/FG ratio was calculated as an index of the Pout.

RESULTS

In the topical group, there were no significant differences in the Pin or F/FG ratio between the LP- and the PBS-treated eyes. In the injection group, the Pin in the LP-treated eyes was significantly higher than in PBS-treated eyes (p < 0.05). There was no significant difference in the F/FG ratio between the two groups.

CONCLUSION

Although we cannot exclude the effect of differences in species, the physiologic effect of LP, which increased the Pin, was seen in experimental studies. Because antiglaucoma drugs are generally used over an extended period, further clinical studies of the effect of LP on the BRB should be performed in patients who have BRB breakdown, such as in uveitis, and in patients who are pseudophakic and aphakic.

Four years later: a clinical update on latanoprost

PURPOSE

Almost five years have elapsed since the introduction of latanoprost on several markets and considering the large number of publications dealing with it, the authors felt that it was worth re-evaluating the drug.

METHODS

The criterion used to select trials for inclusion in the review was: all articles mentioning the drug in common electronic data-bases; these were then screened and considered, on the basis of methodological quality.

RESULTS

Experimental data suggest that latanoprost acts by remodeling the extracellular matrix in the ciliary muscle, thus increasing the flow of aqueous humor through the ciliary muscle bundles of the uveoscleral pathway. POAG: Latanoprost persistently improves the pulsatile ocular blood flow in primary open angle glaucoma (POAG). Recent trials confirmed the greater IOP-lowering efficacy of latanoprost vs. timolol, dorzolamide, brimonidine and unoprostone. Trials lasting up to 24 months showed that latanoprost is effective in long-term treatment of POAG and ocular hypertension (OH), with no signs of loss of efficacy when compared to timolol or dorzolamide. Latanoprost provides better control of circadian IOP. Non-responders to beta-blockers should preferably be switched to latanoprost monotherapy before a combination therapy is started. The possibility of a fixed combination of latanoprost and timolol has been explored, with promising results. NTG: Latanoprost is effective in normal tension glaucoma (NTG), lowering IOP, improving pulsatile ocular blood flow and increasing ocular perfusion pressure. OTHER GLAUCOMAS: Latanoprost may provide effective IOP control in angle-closure glaucoma after iridectomy, in pigmentary glaucoma, glaucoma after cataract extraction and steroid-induced glaucoma. However, latanoprost was effective in only a minority of pediatric cases of glaucoma and is contraindicated in all forms of uveitic glaucoma.

SAFETY

In the articles reviewed, new or duration-related adverse events were reported.

Reappraising first-line treatment in glaucoma management

Despite treatment, glaucoma patients may still suffer vision loss because of inadequate control of intraocular pressure or late presentation. This article reviews the latest evidence supporting a reappraisal of first-line treatment in the management of glaucoma, including a review of latanoprost, recently approved for first-line treatment of glaucoma and ocular hypertension.

Cystoid macular edema in aphakia and pseudophakia after use of prostaglandin analogs

Prostaglandin analogs are powerful ocular hypotensive agents that may also be associated with a breakdown of the blood-retinal barrier and cystoid macular edema. The association is evident in pseudophakic or aphakic patients. This paper presents a case of unilateral latanoprost-associated clinical cystoid macular edema in a bilaterally pseudophakic patient; the only difference between the two eyes was the presence of a capsulotomy in the affected eye. We review the literature concerning prostaglandin analog-associated cystoid macular edema, as well as the evidence for prostaglandin analog-associated breakdown of the blood-retinal barrier. Although some evidence is suggestive of a connection between prostaglandin analogs and cystoid macular edema, many questions concerning the complex physiology of prostanoids remain. Until our understanding of these issues is more advanced, judicious use of prostaglandin analogs in patients at risk for cystoid macular edema would be prudent.

Prostaglandins and cystoid macular edema

This review discusses the roles and interactions of prostaglandins and other possible chemical mediators in cystoid macular edema. Prostaglandins have been studied as a potential causative factor of cystoid macular edema following cataract/intraocular lens surgery. The authors' hypothesis and data with regard to the mechanisms of postoperative cystoid macular edema and other inflammatory conditions are presented. The effects of nonsteroidal anti-inflammatory drugs, which are antagonists of prostaglandin biosynthesis, on postoperative inflammatory conditions including cystoid macular edema are also reviewed. Lastly, a mechanism for the induction of cystoid macular edema by anti-glaucoma eyedrops, including prostaglandin analogs is proposed. The results from two clinical trials recently conducted by the authors suggest that the preservative rather than the active ingredient is the causative factor.

Current status of prostaglandin therapy: latanoprost and unoprostone

Latanoprost, a prostaglandin F(2alpha) analog prodrug, and unoprostone, an analog of a prostaglandin metabolite, have been shown to be effective in decreasing intraocular pressure when used alone or in combination with other ocular hypotensive agents. The increase in the uveoscleral outflow and some of the side effects are probably FP-receptor mediated, which may account for some differences between the cited drugs. This article reviews the recent literature available on the clinical efficacy of these prostanoids, as well as the studies directly comparing these drugs.

Putative side effects of prostaglandin analogs

Anecdotal case reports describe the occurrence of cystoid macular edema, iritis, herpes simplex keratitis, periocular skin darkening, and headaches in patients treated with prostaglandin analogs for glaucoma. The purpose of this article is to critically analyze these anecdotal case reports in light of a few well-controlled, randomized clinical studies to determine whether conclusions can be made about a causal relationship between the use of prostaglandin analogs and the occurrence of these side effects. None of these putative side effects has been proven to be causally related to latanoprost therapy using valid scientific methodology. These possible side effects occur rarely. Cystoid macular edema, iritis, and herpes simplex keratitis occur in eyes with risk factors. To scientifically establish a causal relationship between drug therapy and rare side effects, repeated rechallenging with masked controls is required. With rare exception, such methodology has not been used with any of these putative side effects. Nevertheless, even without firm establishment of a causal relationship, caution is advised with the use of prostaglandin analogs in eyes with risk factors for cystoid macular edema, iritis, and herpes simplex keratitis until properly designed, large, controlled studies provide more definitive information.

Cystoid macular edema in the era of ocular hypotensive lipids

PURPOSE

To review cystoid macular edema in relationship with ocular hypotensive lipids and to present recommendations for use in eyes at increased risk of cystoid macular edema.

DESIGN

Focused literature review and authors' clinical experience.

METHODS

Cystoid macular edema in association with cataract surgery, epinephrine therapy, and ocular hypotensive lipid therapy is reviewed.

RESULTS

Cystoid macular edema may be associated with a variety of therapeutic interventions, predominantly in eyes at increased risk with open or absent posterior lens capsule and ocular inflammation. Based primarily on experience with latanoprost, the association between ocular hypotensive lipids and cystoid macular edema, even in high-risk eyes, although present, appears to be low.

CONCLUSIONS

Considering the low incidence of cystoid macular edema associated with latanoprost therapy, the authors feel that after maximal tolerable medical therapy and with proper precautions, the use of an ocular hypotensive lipid is an acceptable alternative to filtration surgery in high-risk eyes.

Comparison of topical travoprost eye drops given once daily and timolol 0.5% given twice daily in patients with open-angle glaucoma or ocular hypertension

PURPOSE

This 9-month study compared the intraocular pressure (IOP)-lowering efficacy and safety of once-daily travoprost ophthalmic solutions (0.0015% and 0.004%) with twice-daily timolol 0.5%.

PATIENTS AND METHODS

This study was conducted using a double-masked, randomized, parallel-group design; adult patients with open-angle glaucoma or ocular hypertension (IOP between 24 and 36 mm Hg, inclusive at 9 am and between 21 and 36 mm Hg, inclusive, at 11 am and 4 pm on two eligibility visits after an appropriate washout of previous treatments). In both eyes, the travoprost vehicle (placebo) was instilled at 9 am and travoprost (0.0015% or 0.004%) was instilled at 9 pm, or timolol 0.5% was instilled at both times. The primary efficacy variable was mean IOP measured at 9 am, 11 am, and 4 pm at baseline and follow-up visits.

RESULTS

Five hundred seventy-three patients were randomized to the study treatments. Mean IOP, which was combined across study visits, was lower with travoprost 0.004% than with timolol 0.5% at 9 am (P = 0.0246), 11 am (P = 0.0039), and 4 pm (P = 0.0004). Intraocular pressure was lower with travoprost 0.004% than with travoprost 0.0015% at 11 am (P = 0.0314), the time of peak drug activity. Mean IOP was consistently lower with travoprost 0.0015% than with timolol 0.5%. Mean IOP reductions from baseline were significantly (P less than equal 0.0001) greater with travoprost 0.004% (8.0-8.9 mm Hg) than with timolol 0.5% (6.3-7.9 mm Hg). The most frequent related adverse events were hyperemia, pruritus, discomfort, pain, and iris pigmentation changes. The local tolerance was better in the timolol group compared with patients receiving travoprost. There were no serious unexpected treatment-related adverse events in any group.

CONCLUSIONS

Travoprost 0.004% reduced diurnal mean intraocular pressure significantly more than timolol 0.5%. Both concentrations of travoprost were well tolerated and safe for use in patients with open-angle glaucoma or ocular hypertension.

The pros and cons of different prostanoids in the medical management of glaucoma

The prostaglandin analogs are new exciting drugs added to the therapeutic armamentarium for patients with glaucoma. Several studies have evaluated the ocular hypotensive properties and side effects of latanoprost in different forms of glaucoma. This drug, seems to be the most effective intraocular pressure (IOP)-reducing agent currently available, and has a low incidence of ocular and systemic side effects. Fewer data are available regarding unoprostone, but the IOP-reducing effect of this drug seems to be comparable or slightly inferior to that of timolol and it produces fewer side effects. When compared with unoprostone, latanoprost has been shown to effect a greater reduction in IOP. A major drawback to the use of prostaglandin analogues is the lack of long-term experience such as that currently available for other classes of agents.

Therapeutic potential of prostaglandin analogues in glaucoma

One of the most recent contributions to the therapeutic arsenal available for the treatment of glaucoma is the prostaglandin (PG) analogues. They represent a new class of ocular hypotensive drugs, targeting the uveoscleral outflow of ocular aqueous humour. Two drugs, latanoprost and unoprostone, are presently commercially available. In terms of intraocular pressure (IOP) reduction, latanoprost is the most powerful drug in clinical use today. The once daily dosing promotes compliance. Additional effect is achieved in combination with other hypotensive drugs, including those that increase trabecular outflow facility. The most frequent side effect is increased iris pigmentation that seems to be irreversible. A low frequency of cystoid macular oedema has been reported, predominantly in patients whose blood-retinal barrier (BRB) is compromised. Systemic side effects are rare. The experience with unoprostone is still much less than that with latanoprost. The ocular hypotensive mechanism of action of unoprostone is not well documented but an increase in uveoscleral outflow may be at least a part of its mode of action. Systemic side effects are rare and the ocular side effects seem to be mild. The ocular hypotensive effect is less than that of latanoprost and may not be suitable for monotherapy. It is widely accepted that the IOP alone is not responsible for the development of glaucomatous visual defects. It remains to be seen if this class of drugs will preserve vision in glaucoma patients better than other classes. More PG analogues are under development for potential clinical use.