Ocular Symptoms and Signs with Preserved and Preservative-Free Glaucoma Medications

In vitro effects of preservative-free and preserved prostaglandin analogs on primary cultured human conjunctival fibroblast cells

PURPOSE

Long-term use of topical medication is needed for glaucoma treatment. One of the most commonly prescribed classes of hypotensive agents are prostaglandin analogs (PGs) used as both first-line monotherapy; as well as in combination therapy with other hypotensive agents. Several side effects of eye drops can be caused by preservatives. The purpose of this study was to evaluate the effects of PGs with varying concentrations of benzalkonium chloride (BAC), alternative preservatives, or no preservatives on human conjunctival fibroblast cells.

METHODS

Primary human conjunctival fibroblast cells were used in these experiments. Cells were exposed to the following drugs: BAC at different concentrations, bimatoprost 0.01% (with BAC 0.02%), latanoprost 0.005% (with BAC 0.02%), tafluprost 0.0015% with/without 0.001% BAC and travoprost 0.004% (with 0.001% Polyquad) for 15 and 30 minutes. Cell cytotoxicity was evaluated by phase-contrast microscopy to monitor morphological changes of cells, Counting Kit-8 (CCK-8) assay to cell viability, and fluorescent activated cell sorting (FACS) analysis to measure apoptosis.

RESULTS

BAC caused cell shrinkage and detachment from the plate in a dose-dependent manner. Morphological changes were observed in cells treated with bimatoprost 0.01% and latanoprost 0.005%. However, mild cell shrinkage was noted in cells treated with tafluprost 0.0015%, while a non-toxic effect was noted with travoprost 0.004% and preservative-free tafluprost 0.0015%. CCK-8 assay and FACS analysis showed all groups had a significantly decreased cell viability and higher apoptosis rate compared with the control group. However, travoprost 0.004% and preservative-free tafluprost 0.0015% showed lower cytotoxicity and apoptosis rate than other drugs.

CONCLUSIONS

This in vitro study revealed that BAC-induced cytotoxicity is dose-dependent, although it is important to emphasize that the clinical significance of toxicity differences observed among the different PGs formulations has not yet been firmly established. Alternatively preserved or preservative-free glaucoma medications seem to be a reasonable and viable alternative to those preserved with BAC.

Benzalkonium chloride and glaucoma

Glaucoma patients routinely take multiple medications, with multiple daily doses, for years or even decades. Benzalkonium chloride (BAK) is the most common preservative in glaucoma medications. BAK has been detected in the trabecular meshwork (TM), corneal endothelium, lens, and retina after topical drop installation and may accumulate in those tissues. There is evidence that BAK causes corneal and conjunctival toxicity, including cell loss, disruption of tight junctions, apoptosis and preapoptosis, cytoskeleton changes, and immunoinflammatory reactions. These same effects have been reported in cultured human TM cells exposed to concentrations of BAK found in common glaucoma drugs and in the TM of primary open-angle glaucoma donor eyes. It is possible that a relationship exists between chronic exposure to BAK and glaucoma. The hypothesis that BAK causes/worsens glaucoma is being tested experimentally in an animal model that closely reflects human physiology.

Preservative toxicity in glaucoma medication: clinical evaluation of benzalkonium chloride-free 0.5% timolol eye drops

Timolol (generic name) is a frequently used medication for the control of glaucoma. Benzalkonium chloride (BAK) is a commonly used preservative in ophthalmic solutions with a broad range of antimicrobial activity; however, this nonspecificity can result in toxicity. Adverse effects attributed to BAK, including conjunctival inflammation and fibrosis, tear film instability, corneal cytotoxicity, anterior chamber inflammation, trabecular meshwork cell apoptosis, cataract development, macular edema, and even systemic effects, have been well documented. These effects can lead to ocular discomfort, poor intraocular pressure control, glaucoma surgery failure, and decreased patient compliance. BAK use in topical medications has decreased recently as newer and less toxic preservatives have become available. Yet these preservatives still exert some toxic effects, especially in patients with chronic eye disease who use multiple drops over extended periods of time. Thus, attempts to reduce overall preservative loads for patients are important, whether it be decreasing the amount of preservative, decreasing the total number of drops patients use, or eliminating preservatives entirely. A preservative-free formulation of timolol, TIMOPTIC® in OCUDOSE®, is available in unit-dose vials. Preservative-free unit-dose vials minimize toxic adverse effects and are a good option for patients with ocular surface disease, on long-term multidrop therapy, or who simply do not tolerate the effects of preservatives due to discomfort.

Postoperative pain after cataract surgery

Cataract extraction surgery is the most common surgical procedure, but knowledge of postoperative pain related to cataract surgery is sparse. In this systematic review, the incidence, prevalence, and management of pain after phacoemulsification surgery were identified using PubMed and Scopus. Selected studies were restricted to randomized controlled trials with interventions on postoperative inflammation and pain. Data from 105 articles were extracted and 21 studies met the final inclusion criteria. Most studies reported no or only mild postoperative pain, but some reported moderate and severe pain and pain lasting several weeks. The interventions consisted of drug therapy including topical nonsteroidal antiinflammatory drugs, corticosteroids, paracetamol, perioperative intraocular injections, eye pads used after surgery, and various surgical techniques. The reviewed literature indicates that cataract surgery is associated with significant postoperative pain in some patients, who should be provided with appropriate counseling and pain treatment.

[The effects of ocular hypotensive drugs on the cornea: an in vivo analysis with confocal microscopy]

PURPOSE

To evaluate the effects of anti-glaucoma treatments containing benzalconium chloride (BAC) on the human cornea.

METHODS

A prospective single masked cohort study was conducted on the 50 eyes of 50 patients. The inclusion criteria were: recently diagnosed glaucoma or ocular hypertension with previous treatment, or ophthalmologist-prescribed anti-glaucoma therapy, and oral consent to participate in the study. The patients were not randomised, as the ophthalmologist decided the best therapy according to clinical criteria. The patients were divided in 2 cohorts: one exposed to BAC (23 patients), and not exposed (27 patients). The mean follow-up period was 22 weeks (range 18-30). The change in cell density before and after therapy was measured in: basal layer epithelium, basal layer of limbal epithelium and endothelium. The change in stromal reflectivity and the number of nerve branches in sub-basal nerve plexus was also measured. BAC exposure was blinded to the main researcher.

RESULTS

A greater increase in basal layer epithelium cell density was observed in BAC exposed cohort (P<.05). No significant differences were detected in the endothelium, limbal cell density, stromal reflectivity, or sub-basal nerve plexus. Age, sex, IOP, active ingredient or BAC concentration did not affect the direction or magnitude of the ocular surface alterations found.

CONCLUSION

Chronic anti-glaucoma therapy induces changes in the corneal epithelium. Preservative free drops showed less disruption of the ocular surface by confocal microscopy analysis. Further studies should be conducted to evaluate the clinical impact of these histological findings.

Influence of BAK-preserved prostaglandin analog treatment on the ocular surface health in patients with newly diagnosed primary open-angle glaucoma

Purpose. Primary open-angle glaucoma (POAG), a chronic, degenerative optic neuropathy, requires persistent decrease of intraocular pressure so as to prevent visual impairment and blindness. However, long-term use of topical ocular medications may affect ocular surface health. Purpose of this study was to evaluate the influence of BAK-preserved prostaglandin analog treatment on the ocular surface health in patients with newly diagnosed POAG. Methods. 40 newly diagnosed POAG patients were included in this prospective study. Intraocular pressure (IOP), tear break-up time (TBUT), and ocular surface disease index (OSDI) were assessed at baseline and 3-month after starting treatment with BAK-preserved travoprost 0.004%. Results. IOP decreased in all patients from baseline to 3-month final visit (23.80 ± 1.73 mmHg versus 16.78 ± 1.27 mmHg; P < 0.001). Mean TBUT decreased from 11.70 ± 1.86 seconds at baseline to 8.30 ± 1.29 seconds at 3-month final visit (<0.001). Mean OSDI score increased from 31.63 ± 18.48 to 44.41 ± 16.48 (P < 0.001). Conclusions. This study showed that BAK-preserved travoprost 0.004% is an effective medication in newly diagnosed POAG patients, but its long-term use may negatively influence ocular surface health by disrupting the tear film stability. Further studies are needed to better understand the clinical effects of different preservative types and concentrations on the ocular surface.

Preservative-free Treatment in Glaucoma: Who, when, and why?

Purpose

To review and summarize the available literature on the effect of preservatives on the eye, to provide practical guidance for the clinical assessment of the ocular surface in glaucoma patients, and to define patient populations that might benefit from preservative-free topical intraocular pressure (IOP)–lowering agents.

Methods

This manuscript is based on a combination of a literature review on preservatives and the eye and expert opinion from glaucoma specialists with an interest in ocular surface disease.

Results

There is an increasingly recognized association between eyedrop preservatives and ocular surface disease. Preservative-free therapy is now available for a wide range of active compounds, although there are still some misconceptions regarding their appropriate use. For patients treated topically for glaucoma or ocular hypertension, a rough estimate could be that 20% may need treatment with topical IOP-reducing agents that are free from preservatives.

Conclusions

This review provides an up-to-date account of the literature regarding preservatives and the eye, as well as suggestions and recommendations on to when to use preservative-free antiglaucoma treatment.

Six-month results from a Phase III randomized trial of fixed-combination brinzolamide 1% + brimonidine 0.2% versus brinzolamide or brimonidine monotherapy in glaucoma or ocular hypertension

Background

The objective of this study was to examine the safety and intraocular pressure (IOP)-lowering efficacy of a fixed combination of brinzolamide 1% + brimonidine 0.2% (BBFC) after six months of treatment in patients with open-angle glaucoma or ocular hypertension.

Methods

This was a randomized, multicenter, double-masked, three-month, three-arm contribution-of-elements study with a three-month safety extension. Patients were randomly assigned 1:1:1 to treatment with BBFC, brinzolamide 1%, or brimonidine 0.2% after a washout period. Patients dosed their study medications three times daily at 8 am, 3 pm, and 10 pm for six months. Patients returned for visits at two weeks, six weeks, three months, and six months. IOP measurements were used to assess efficacy. Safety assessments were adverse events, corrected distance visual acuity, slit-lamp biomicroscopy, pachymetry, perimetry, fundus parameters, and cardiac parameters.

Results

A total of 690 patients were randomized. Six-month mean IOP values were similar to those at three months, when the mean IOP in patients treated with BBFC was significantly lower than that of either monotherapy group. A total of 175 patients experienced at least one treatment-related adverse event (BBFC, 33.0%; brinzolamide, 18.8%; brimonidine, 24.7%), eight of which were severe, and five resulted in discontinuation. Seventy-seven patients discontinued participation due to treatment-related adverse events (BBFC, 17.2%; brinzolamide, 2.1%; brimonidine, 14.5%). There were 21 serious adverse events (n = 7 in each group), none of which was related to treatment. Resting mean pulse and blood pressure with BBFC were similar to those with brimonidine, demonstrating modest, clinically insignificant decreases. No new or increased risks were identified with use of BBFC relative to either monotherapy.

Conclusion

This study showed that, after six months of treatment, the safety profile of BBFC was similar to that of its individual components and its IOP-lowering activity was similar to its efficacy at three months, when it was superior to both brinzolamide 1% alone and brimonidine 0.2% alone.

Preservative-free tafluprost in the treatment of naive patients with glaucoma and ocular hypertension

PURPOSE

The study reported here investigated the efficacy, tolerability, and safety of the preservative-free prostaglandin analog tafluprost 0.0015% in treatment-naive patients.

PATIENTS AND METHODS

Data were collected in two non-interventional, prospective, multicenter, observational, open-label studies of identical design that were conducted in Germany and the Czech Republic. All subjects received preservative-free tafluprost 0.0015% once daily. Intraocular pressure (IOP) levels were recorded for each eye at untreated baseline and 3 months after initiation of medical treatment. The primary outcome was change in mean IOP from baseline to month 3. In the primary open-angle glaucoma (POAG) and ocular hypertension (OH) patient subgroups, analyses were stratified by the level of baseline IOP: ≥20 to 23 mmHg versus ≥24 mmHg. In addition, responder rates and the achievement of pre-specified IOP levels at month 3 were evaluated. Local tolerance of preservative-free tafluprost was evaluated by the patients at final visit. Overall satisfaction with the medical treatment was evaluated by both patients and physicians. All adverse events were recorded.

RESULTS

A total of 579 treatment-naive patients with POAG (n = 349), OH (n = 105), normal tension glaucoma (n = 71), exfoliative glaucoma (n = 27), or other glaucomas (n = 27) were included in this observational study. Mean IOP level at baseline for all patients was 23.6 ± 4.0 mmHg. Mean IOP at month 3 was 16.8 ± 2.9 mmHg (-28.8% vs baseline). At month 3, significant reductions in mean IOP (P < 0.001) were seen in all patients and all subgroups. Preservative-free tafluprost lowered mean IOP significantly in patients with POAG and OH with IOP levels ≥ 20 to 23 mmHg from 21.9 ± 1.1 mmHg at baseline to 16.5 ± 2.2 mmHg, and in the subgroup with IOP levels ≥ 24 mmHg from 26.2 ± 2.4 mmHg to 17.9 ± 2.4 mmHg. In the subgroups of patients with POAG and OH, an IOP response ≥20%, ≥30%, and ≥40% was achieved by 83.4%, 44.1%, and 12.8%, respectively. Overall, patients with higher baseline IOP values showed a better response than patients with lower baseline IOP levels. Preservative-free tafluprost was well tolerated and safe. After 3 months, 97.9% of all patients remained on therapy.

CONCLUSION

In this real-world observational study, treatment with once-daily preservative-free tafluprost proved efficacious, well tolerated, and safe in treatment-naive patients.

Glaucoma therapy and ocular surface disease: current literature and recommendations

PURPOSE OF REVIEW

To provide an update on clinical and experimental literature for ocular surface effects of glaucoma therapy and to provide practical guidelines for ophthalmologists treating glaucoma patients with ocular surface disease (OSD).

RECENT FINDINGS

Preservatives, notably benzalkonium chloride (BAK), continue to contribute to OSD and demonstrate a variety of toxic ocular effects both in-vitro, and in animal/human studies. Recent literature frequently compares BAK with Polyquad, SofZia, and preservative-free therapies. Some clinical benefit has been demonstrated with newer BAK-free alternatives.

SUMMARY

BAK-free and preservative-free therapies are becoming available but are not always a feasible alternative. It is important to recognize different clinical manifestations of allergy and chronic inflammation and to discuss options for patients experiencing OSD.

Cell viability score (CVS) as a good indicator of critical concentration of benzalkonium chloride for toxicity in cultured ocular surface cell lines

Cytotoxicity of benzalkonium chloride (BAK) is a major factor affecting drug cytotoxicity. This study aimed to determine the critical concentration of BAK for cultured ocular cells, using SIRC (rabbit corneal epithelium), BCE C/D-1b (bovine corneal epithelial cells), RC-1 (rabbit corneal epithelium), and Chang (human conjunctival cells). Cell viability was determined following the exposure of cells to 11 concentrations of BAK for 10, 30, or 60 min using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and neutral red assays, and the cell viability score (CVS) was used to evaluate comprehensively the toxicity of BAK. The CVS system consists of two values. The CVS50 was determined by the number of measurements for viability ≥50% of control. The CVS40/80 was calculated as follows: CVS40/80=(number of measurements for viability values >80%)-(number of measurements for viability values <40%). Both %CVS50 and %CVS40/80 decreased with concentrations of BAK. When BAK concentrations were 0.01% or higher, %CVS50 and %CVS40/80 became 0 and less than -90, respectively. Meanwhile, when BAK concentrations were 0.001% or lower, %CVS50 became 100. In the case of %CVS40/80, when the BAK concentrations were 0.002% or lower, the values reached 75 or more, and when 0.0005% or lower, the %CVS40/80 value reached 100. Accordingly, BAK induced very low cytotoxicity in the cultured ocular cell lines at concentrations of 0.002% or lower. The concentration-dependency confirmed that the CVS score is useful for expressing drug cytotoxicity in a simple and comprehensive manner.

Phase 3 randomized 3-month trial with an ongoing 3-month safety extension of fixed-combination brinzolamide 1%/brimonidine 0.2%

PURPOSE

This study compared the intraocular pressure (IOP)-lowering efficacy of fixed-combination brinzolamide 1%/brimonidine 0.2% (BBFC) with that of its component medications, brinzolamide and brimonidine, in patients with open-angle glaucoma or ocular hypertension.

PATIENTS AND METHODS

In this phase 3, multicenter, double-masked, parallel-group, 3-month study with a 3-month safety extension, eligible patients were randomized 1:1:1 to treatment with BBFC, brinzolamide, or brimonidine thrice daily after a washout period, during which any IOP-lowering medications were discontinued. The primary objectives of this study were to determine whether the IOP-lowering efficacy of BBFC was superior to that of brinzolamide alone and, separately, of brimonidine alone. IOP was assessed at 8:00 AM, 10:00 AM, 3:00 PM, and 5:00 PM at 2 weeks, 6 weeks, and 3 months after study drug initiation.

RESULTS

A total of 690 patients were enrolled in the study, and 615 completed the 3-month visit. Baseline mean IOP levels were similar among the 3 treatment groups at each of the 4 time points assessed. At the 3-month primary endpoint, mean IOP of the BBFC group was significantly lower than that of either the brinzolamide group or the brimonidine group (P≤0.005) across all time points. At the 2- and 6-week supportive endpoints, mean IOP of the BBFC group was significantly lower at all time points than the mean IOP of either the brinzolamide group (P≤0.01) or the brimonidine group (P<0.0001). A total of 143 patients experienced at least 1 treatment-related adverse event (AE; BBFC group, n=58, 26.2%; brinzolamide group, n=44, 18.8%; brimonidine group, n=41, 17.4%), the majority of which were ocular AEs.

CONCLUSIONS

This study demonstrated that BBFC has significantly superior IOP-lowering activity compared with either brinzolamide 1% or brimonidine 0.2% in patients with open-angle glaucoma or ocular hypertension while providing a safety profile which is consistent with that of the individual components.

Effects of SofZia-preserved travoprost and benzalkonium chloride-preserved latanoprost on the ocular surface -- a multicentre randomized single-masked study

PURPOSE

To assess the effect of SofZia-preserved travoprost on ocular surface conditions in comparison with benzalkonium chloride (BAK)-preserved latanoprost.

METHODS

A prospective randomized multicentre single-masked comparative study. Patients with open-angle glaucoma or ocular hypertension who had been treated with BAK-preserved latanoprost 0.005% (Xalatan(®) ) monotherapy for at least 3 months. Patients were enrolled at 23 facilities. Patients were randomly divided into the X-X group, continuous use of Xalatan(®) , or the X-T group, switching from Xalatan(®) to SofZia-preserved travoprost 0.004% (TravatanZ(®) ), and followed for 3 months. The superficial punctate keratopathy (SPK), conjunctival epitheliopathy, hyperaemia, tear break-up time (TBUT) and intraocular pressure (IOP) were examined for each patient in a masked manner. Changes in the frequency of keratoconjunctival epitheliopathy were evaluated 3 months after study initiation. Intra- and intergroup comparisons of changes in SPK, conjunctival epitheliopathy, hyperaemia, TBUT and IOP were also carried out.

RESULTS

Two hundred twenty patients participated and 215 completed the 3-month study. The frequency of keratoconjunctival epitheliopathy significantly decreased in the X-T group (p = 0.036) and the intergroup difference was also significant (p = 0.001). SPK scores and TBUT were significantly improved in the X-T group (p = 0.034, 0.049), also with significant intergroup differences in the cornea excluding the inferior area and TBUT. There were no significant intergroup differences in changes of the hyperaemia scores and the IOP reduction.

CONCLUSION

Switching to SofZia-preserved travoprost after BAK-preserved latanoprost resulted in a lower incidence of keratoconjunctival epitheliopathy, especially in the cornea, with no clinically relevant changes in hyperaemia and IOP.

Toxic-inflammatory effects of prostoglandin analogs on the ocular surface

PURPOSE

To investigate the toxic-inflammatory effects of prostaglandin analogs on the ocular surface.

MATERIALS AND METHODS

Twenty-three rats were divided into four groups. Bimatoprost 0.03% (I), latanoprost 0.005% (II), and travoprost 0.004% (III) were applied during 6 months; a control group (IV) received no treatment. Dysplasia and keratinization were evaluated on the ocular surface. In the subepithelial area, the number of lymphocytes and mast cells were counted morphologically, and collagen staining densities were compared subjectively in groups.

RESULTS

The ratio of keratinization was 3/12 and 1/10, in groups I and II. The lymphocyte cell counts were 1.4 ± 0.19, 2.2 ± 0.39, 2.27 ± 0.33, and 1.87 ± 0.35 (p > .05). The mast cell counts were 2.58 ± 0.5, 5.4 ± 1.1, 5.7 ± 0.58, and 3.0 ± 0.59. They were significantly higher in groups II and III than in group I (p < .05). Mean collagen density scores were 1.00 ± 0.85, 2.00 ± 0.00, and 1,73 ± 0.70. Group II and III scores were higher than group I scores (p < .05).

CONCLUSION

Latanoprost and travoprost seem to have more toxic-inflammatory effects on the ocular surface than bimatoprost.

CX3CL1 expression in the conjunctiva is involved in immune cell trafficking during toxic ocular surface inflammation

Inappropriate expression of the chemokine CX3CL1 is reportedly known to act on inflammatory conditions in extraocular immune diseases. We studied the expression and effects of CX3CL1 in human patients, cultured human conjunctival cells, and transgenic mice exposed to benzalkonium chloride (BAC), a commonly used preservative in ophthalmic medications despite its proinflammatory properties, to determine whether CX3CL1 is involved in conjunctival inflammation. We report that CX3CL1 expression is increased in the conjunctiva of patients receiving BAC-containing medication, and correlates with clinical inflammation. BAC enhances the production of CX3CL1 in a conjunctival epithelial cell line, through the tumor-necrosis factor-α pathway, which attracts specific leukocyte subsets. In vivo, BAC-induced macrophage infiltration and subsequent inflammation of the conjunctiva is decreased in CX3CR1-deficient mice as compared with CX3CR1(+/+) controls. This translational study opens new avenue to investigate ocular surface disorders by focusing on chemokine-related inflammation and immune cell trafficking in the ocular conjunctival mucosa.

Tear film osmolarity in patients treated for glaucoma or ocular hypertension

PURPOSE

To evaluate tear film osmolarity in patients treated with intraocular pressure-lowering medications.

METHODS

Forty patients treated for glaucoma or ocular hypertension (OHT) were consecutively recruited for the study. Each patient was asked to complete an evaluation of ocular surface disease symptoms, the Ocular Surface Disease Index, and underwent a complete evaluation of the ocular surface including measurement of tear film osmolarity, Schirmer test, tear breakup time (TBUT), and corneal and conjunctival staining.

RESULTS

Twenty-four patients (60%) reported ocular surface disease symptoms. Nineteen patients (47.5%) had a tear osmolarity ≤308 mOsms/L, 11 (27.5%) between 309 and 328 mOsms/L, and 10 (25%) >328 mOsms/L. A tear deficiency was observed in 20 patients (50%). Twenty-seven patients (67.5%) had an abnormal tear quality analyzed with TBUT, and 16 patients (40%) showed positive staining using the Oxford schema. Tear osmolarity was significantly correlated to Ocular Surface Disease Index (r = 0.486; P = 0.002) and TBUT (r = -0.49; P = 0.009). There was a statistically significant correlation between tear osmolarity and the number of drugs (r = 0.409; P = 0.009), the number of instillations (r = 0.405; P = 0.01), and the number of instillations of preserved eye drops (r = 0.629; P < 0.0001). Using the multiple regression method, tear osmolarity remained significantly correlated to the number of instillations of preserved eye drops (P = 0.004).

CONCLUSION

Tear osmolarity was increased in patients treated for glaucoma or OHT, particularly in those using multiple preserved eye drops. The evaluation of the ocular surface of patients treated for glaucoma or OHT may benefit from such analysis, and future trials for new intraocular pressure-lowering eye drops should thus evaluate tear osmolarity.

Controversy: Is Benzalkonium Chloride Necessary in Antiglaucoma Drops?

Medical therapy is the first-line option in glaucoma management, with benzalkonium chloride (BAC) being the most frequently used preservative in antiglaucoma medications. Its use is however, known to be associated with deleterious effects on the ocular surface. This review is an attempt to critically evaluate whether BAC really is indispensable for better bioavailability of antiglaucoma drugs and consequently, better IOP control.

How to cite this article: Louati Y, Shaarawy T. Controversy: Is Benzalkonium Chloride Necessary in Antiglaucoma Drops? J Current Glau Prac 2012;6(3):104-107.

The role of medications in causing dry eye

The purpose of this paper is to review the possible role of polypharmacy in causing dry eye disease (DED), reflecting the complex interactions and complications associated with the use of multiple systemic and topical ocular medications. The pharmacological, physiological, anatomical, and histological mechanisms causing dry mouth differ little from those causing dry eye. Oral polypharmacy is the most common cause of dry mouth, but has not been investigated as a cause of dry eye. Topical ocular polypharmacy has been shown to cause DED. Information on drugs that likely cause or aggravate DED and the controversial role of preservatives in topical ocular medications are examined. Systemic or topical ocular medications and preservatives used in topical ocular drugs may cause dry eye through the drug's therapeutic action, ocular surface effects, or preservatives, and the effects probably are additive. Long-term use of topical ocular medications, especially those containing preservatives such as BAK, may play an important role in DED and the role of polypharmacy needs further study. We review possible ways to decrease the risk of medication-related dry eye.

Prevalence and risk factors for ocular surface disease among patients treated over the long term for glaucoma or ocular hypertension

Purpose. To determine the prevalence of ocular surface diseases and identify risk factors in a population of patients receiving antiglaucomatous eyedrops over the long term. Methods. An observational cross-sectional study was designed to investigate ocular surface signs and symptoms using simple clinical tools. An ocular surface disease intensity score was calculated based on 10 questions regarding ocular surface symptoms and signs with a 4-grade scale. Patients were classified into 3 groups (A, B, and C) according to this total score. A multinomial logistic regression was performed in order to identify risk factors for surface disease. Results. In an overall population of 516 patients, 49% belonged to group A, 30% to group B, and 21% to group C. The multivariate analysis showed that the following factors were correlated with the severity of ocular surface disease: patient age, number of daily eyedrops, past topical treatment changes for ocular intolerance (found in the history of 40% of the patients), intraocular pressure (found to be significantly higher in patients with more severe ocular surface disease), and glaucoma severity. Conclusions. Patients treated for primary open-angle glaucoma or ocular hypertension often have ocular surface diseases, more often and more severely in older patients receiving more drugs and presenting with more severe glaucoma. These high prevalence values might therefore have consequences on the burden of the disease in terms of adherence to treatment and quality of life.

Benzalkonium chloride induces anterior chamber inflammation in previously untreated patients with ocular hypertension as measured by flare meter: a randomized clinical trial

PURPOSE

The deleterious effects of benzalkonium chloride (BAK) on the ocular surface are well known. However, few clinical data are available to prove a toxic effect at the level of the anterior chamber. The laser flare meter is a reliable tool to detect low levels of inflammation in the anterior chamber. We wanted to know whether instillation of BAK-preserved timolol in one eye would result in higher laser flare values than the instillation of preservative-free timolol in the fellow eye.

METHODS

Randomized prospective, single-masked clinical trial. Twenty-eight untreated patients with ocular hypertension were recruited. After obtaining baseline flare values, we randomly assigned one eye to BAK-preserved timolol and the fellow eye to preservative-free timolol. After 1 month, flare measurements were repeated.

RESULTS

There was a significant increase in the flare values in the two treatment regimens, but the increase in the BAK-treated eyes was higher than in the preservative-free treated eyes, and this difference in increase was statistically significant.

CONCLUSION

This is the first study to show that short-term BAK administration produces inflammation in the anterior segment of previously untreated patients whose blood-aqueous barrier was not affected by recent intraocular surgery.

[Arguments against pressure-lowering treatment of ocular hypertension. Prophylactic treatment is unnecessary]

The main argument against a pressure-lowering treatment for patients with ocular hypertension (OHT) is the principle of "first do no harm". The imprecision of intraocular pressure (IOP) measurements and the fact that increased IOP is only a risk factor for glaucoma raise major doubts on a clinical definition of OHT. The use of IOP-lowering treatment in the absence of functional or morphological glaucomatous changes should only be initiated if the IOP is very high (>32 mmHg). If the IOP is between 21 and 32 mmHg the glaucoma conversion risk of the individual patient should be estimated. The risk factors as proven in major prospective trials (OHTS/EGPS) should be assessed using the risk calculator. Only patients with a high risk (>13%) of conversion profit from prophylactic IOP-lowering treatment. For all patients with intermediate or low risk of conversion the potential side-effects (local and systemic) of the treatment outweigh the possible benefit, so that the principle of "watchful waiting" is the best for patients with OHT. If morphological or functional progression is observed IOP-lowering treatment should be started immediately.

Preservative use in topical glaucoma medications

Benzalkonium chloride (BAK) is the principal preservative employed in topical ocular hypotensive medications, although alternative compounds recently have begun to be employed or examined. Individual clinical trials have shown that exposure to BAK concentrations contained in ophthalmic solutions does not produce adverse sequelae in the majority of glaucoma patients, but concerns continue with regard to its long-term use. These concerns have resulted from an extensive research effort, including preclinical studies with in vitro and in vivo models, as well as recent clinical investigations dedicated specifically to this issue. The aim of this systematic literature review of both preclinical and clinical data was to determine the relevance of these findings to clinical practice. Most preclinical studies reported negative effects of BAK exposure, but with few exceptions, BAK concentrations and exposure times greatly exceeded those likely to be experienced by patients, given the normal physiological dilution by the tear film. In addition, consistent evidence of BAK-related toxicity did not emerge from our review of dedicated clinical investigations. Thus, taken together, current evidence supports the safety of BAK for most glaucoma patients, although subpopulations with abnormal tearing may benefit from alternative preservative compounds or preservative-free formulations. Further studies to identify these populations are needed.

[Corneal sensitivity in patients treated medically for glaucoma or ocular hypertension]

PURPOSE

To evaluate the corneal sensitivity in patients treated with intraocular pressure (IOP)-lowering medications.

INTRODUCTION

Chronic administration of anti-glaucoma drops is associated with numerous tissue changes on the ocular surface. The purpose of this study was to investigate the effect of these medications and their preservative, benzalkonium chloride (BAK), on corneal sensitivity.

PATIENTS AND METHODS

Thirty-nine patients treated for glaucoma or ocular hypertension (OHT) and nine untreated patients were included in this study. Treated patients were divided into three groups according to the daily number of preserved eyedrops (0, 1 and ≥2). Corneal sensitivity was assessed using the Cochet-Bonnet esthesiometer. All patients underwent a complete examination of the ocular surface including Schirmer testing, tear film breakup time (BUT) and corneal and conjunctival fluorescein staining. The Ocular Surface Disease Index (OSDI) questionnaire was used to evaluate symptoms.

RESULTS

Corneal sensitivity was 58.8±2.8mm, 56.2±5.2mm, 50.3±12.5mm and 44.3±13.6mm in untreated patients, in patients treated with none, one and two or more instillations of preserved eyedrops, respectively. Corneal sensitivity in patients treated with preserved eyedrops was significantly lower as compared to untreated patients (P<0.001) and patients treated with preservative-free eyedrops (P=0.012). Corneal sensitivity of patients treated with intraocular pressure-lowering medications was negatively correlated to the number of instillations of preserved eyedrops (r=-0.390 ; P<0.001) as well as to the duration of treatment (R=-0.357 ; P=0.001). BUT and fluorescein staining were significantly altered in treated patients compared to the untreated control group ; however, no significant difference was observed between the treated groups. There was no significant difference for OSDI or Schirmer testing between the various groups.

CONCLUSION

Chronic administration of BAK-containing anti-glaucoma eyedrops appears to alter corneal sensitivity. These results could explain the absence of correlation between clinical signs and symptoms sometimes observed in patients treated for glaucoma or OHT.

Challenges in the clinical measurement of ocular surface disease in glaucoma patients

Ocular surface disease (OSD) is common among glaucoma patients. Clinical assessment of OSD can be challenging. This review focuses on some of the limitations relating to both subjective and objective measures of OSD, including dry eye. A survey of the literature was conducted to identify the caveats associated with different methods of assessing OSD. The effect of preservatives on the ocular surface, with respect to glaucoma patients in particular, was also reviewed. Objective methods for assessing ocular surface health and disease include the Schirmer test, tear break-up time, fluorescein turnover, corneal and conjunctival staining, tear osmolarity, and vital dyes. These measures all have limitations in terms of their ability to grade the severity of OSD. Previous studies using the OSD Index showed a mild-to-moderate correlation to dry eye disease severity. Other scoring systems for dry eye have shown a relationship to patient symptom scores or quality of life. Due to the challenges clinicians face concerning both subjective and objective ocular surface health assessments, discerning clinical improvement in ocular surface disease can be a challenge. Further research is needed in order to optimize existing clinical methods and/or identify alternative techniques for assessing OSD in the glaucoma population.

A double-masked study to compare the efficacy and safety of topical cromolyn for the treatment of allergic conjunctivitis

BACKGROUND/PURPOSE

To compare the efficacy and safety of topical cromolyn between with and without preservative for the treatment of allergic conjunctivitis.

METHODS

A double-masked study was performed in patients with allergic conjunctivitis. Each cromolyn sodium 2% ophthalmic solution with or without 0.01% benzalkonium chloride (BAK) was randomized to apply on either eye. The efficacy and safety were evaluated every other week by a questionnaire about ocular itching, redness and foreign body sensation, and objective scores of conjunctival redness, chemosis, cornea erosion and discharge using slit-lamp biomicroscopy. An overall response was also rated by physician's impression.

RESULTS

A total of 37 subjects were enrolled in this study but only 33 completed the study. All of subjective questionnaire scores showed a significant improvement after treatment in both groups. Objective score of redness significantly decreased after treatment in either groups but not chemisos or discharge. After 4-week treatment, corneal erosion diminished significantly in the group without preservative but not in the group with 0.01% BAK. There was no significant difference between with and without 0.01% BAK groups in each subjective or objective score. No adverse effect related with medication was observed.

CONCLUSION

Cromolyn 2 % ophthalmic solution was effective and safe to treat allergic conjunctivitis. A short-term use of cromolyn 2 % ophthalmic solution with 0.01% BAK would not cause any significant toxicity in patients with allergic conjunctivitis. Preservative-free cromolyn may be beneficial to the compromised eyes or eyes required of long-term medication.

Antiglaucoma drugs: The role of preservative-free formulations

Hypersensitive reactions to eyedrops are a common finding in clinical practice and represent a frequent cause of discontinuation of the therapy. Moreover, experimental and clinical studies show that long term use of topical drugs may induce ocular surface changes causing discomfort and potentially negatively affecting the compliance to the treatment as well as the success rate of filtering procedures. The exact mechanism involved and the roles of the active compound and the preservatives in inducing such detrimental effects of ophthalmic solutions are unclear. During the last years several antiglaucoma agents have been marketed as either preservative-free or benzalkonium chloride-free formulations in an attempt to reduce the adverse effects related to preservatives. This paper summarizes the body of evidence from existing studies about preservatives in antiglaucoma eyedrops, focusing on the latest compounds commercially available. A systematic review of the literature was performed. Current research is focusing not only on the efficacy of the drugs but also on their tolerability. Based on the existing data, there is a rationale to support the use of benzalkonium-free solutions whenever possible, especially in patients suffering from concomitant ocular surface diseases, experiencing local side effects and in those expected to need multiple and prolonged topical treatments.

[The influence of ocular surface diseases in the management of glaucoma]

INTRODUCTION

The medical treatment of glaucoma is frequently used as a first-line treatment. Often effective, this treatment is administered over the long term. Chronic administration of eye drops is implicated in ocular surface disease. The objective of this study was to determine the prevalence of ocular surface diseases (OSDs) in patients treated for glaucoma or ocular hypertension (OHT) as well as their influence on therapeutic management.

PATIENTS AND METHODS

Eighty-eight patients followed at the Quinze-Vingts National Ophthalmology Hospital for glaucoma or OHT were evaluated. All patients had a complete ocular examination including an evaluation of the ocular surface. A questionnaire derived from the Ocular Surface Disease Index (OSDI) was used to assess ocular surface symptoms and the related impairment of quality of life. According to the clinical evaluation of the ocular surface, patients were classified into three groups (A, no OSD; B, moderate OSD; C, severe OSD. The patients for whom ocular surface disease had modified the therapeutic management of glaucoma were identified.

RESULTS

In this study, 72 patients (82 %) showed significant symptoms of OSDs (OSDI score>22). A moderate or severe OSD was observed in 67 patients (76 %). For 33 patients (38 %), the OSD influenced the choice of glaucoma or OHT treatment. Among these patients, six had glaucoma surgery, one had laser trabeculoplasty, and 26 required one or several changes in eyedrops.

CONCLUSION

This study confirmed the high prevalence of OSDs in patients treated for glaucoma or OHT. For numerous patients, these pathologies influenced not only their quality of life but also their therapeutic management.

Role of benzalkonium chloride in DNA strand breaks in human corneal epithelial cells

PURPOSE

To investigate the toxic effects of benzalkonium chloride (BAC), a preservative commonly used in ophthalmic preparations, on DNA single- and double-strand breaks in immortalized human corneal epithelial cells (HCEs).

METHODS

HCEs were treated with BAC in concentrations ranging from 0.00005% to 0.001% for 30 min. Cells were examined immediately after BAC exposure and after 24-h recovery. Alkaline comet assay was used to detect DNA single-strand breaks (SSBs). Immunofluorescence microscope detection of the phosphorylated form of histone variant H2AX (γH2AX) foci indicated DNA double-strand breaks (DSBs). Cell viability was measured by the MTT test.

RESULTS

A significant increase of SSBs, detected by alkaline comet assay, was observed in a dose-dependent manner with BAC exposure in HCEs at concentrations of 0.00005% and higher. Such BAC treatment also exhibited a dose-dependent increase in DSBs, evaluated by number of γH2AX foci. In addition, a significant change in the relative cell survival rate of HCEs was observed after exposure to 0.001% BAC for 30 min. Although the toxic effects of BAC could be partly repaired after 24 h of cell recovery, SSBs and DSBs in HCEs were still present after BAC removal.

CONCLUSIONS

The results demonstrated that exposure to BAC in HCEs, even at low concentrations, could induce DNA strand breaks, which were present after BAC removal. Cell survival analysis indicated that BAC-induced DNA damage was correlated with the cytotoxic effects.

Ocular surface disease in patients with ocular hypertension and glaucoma

PURPOSE

To review the prevalence, diagnosis, causes, and treatment of ocular surface disease (OSD) in patients with ocular hypertension or primary open-angle glaucoma.

METHODS

A review of the literature pertaining to OSD and glaucoma.

RESULTS

Recent studies indicate that OSD demonstrates an overall prevalence in glaucoma of 42% (range 20-59%) and is severe in 36% (range 14-66%). Further, the prevalence appears to increase with the greater the number of glaucoma drugs prescribed. Symptoms and signs are non-specific to the anterior surface of the eye and are thought to result from allergic, toxic, or pro-inflammatory conditions. However, the specific causes remain incompletely described, but may result from the benzalkonium chloride (BAK) preservative or occasionally the ocular hypotensive active molecule itself. Additionally, anterior segment ocular diseases might be causative, such as allergy, blepharitis, dry eye, and eyelid anatomical abnormalities. Treatment may consist of using preservative-free or non-BAK preserved glaucoma medications. Also, although unproven specifically in glaucoma patients, treatment of associated diseases of the anterior surface might reduce signs and symptoms.

CONCLUSIONS

OSD is common in treated glaucoma patients causing symptoms and signs that may impact on a patient's quality of life. Treatment is directed towards any underlying disease process and the use of preservative-free or non-BAK-preserved glaucoma preparations.

Incidence of new coding for dry eye and ocular infection in open-angle glaucoma and ocular hypertension patients treated with prostaglandin analogs: retrospective analysis of three medical/pharmacy claims databases

Background

To investigate the clinical relevance of two different preservative formulations, we compared 1-year incidence rates of additional coding of dry eye, ocular infection, or ocular surface disease (either dry eye or ocular infection) in open-angle glaucoma and ocular hypertension patients newly treated with latanoprost with benzalkonium chloride (BAK) or with travoprost-Z with SofZia^®.

Methods

This was a retrospective study of three U.S.-based patient-centric medical/pharmacy claims databases (MedStat, PharMetrics, i3-Ingenix). Patients were eligible if they filled a prescription for latanoprost or travoprost-Z between October 2006 and Q2 2008 (prescription date = index date) AND were continuously enrolled 6 months prior through 12 months after the index date AND had any open-angle glaucoma or ocular hypertension diagnosis within 90 days prior to the index date AND did not have an ocular surface disease diagnosis during the 180 days prior to the index date AND if they had not had a prescription for the index agent in the 180 days prior to the index date. Time to incidence of new coding for ocular surface disease in the first year post-index was estimated with a composite endpoint: diagnosis of dry eye or ocular infection by ICD-9-CM or Current Procedural Terminology code OR by prescription for cyclosporine ophthalmic emulsion or ocular antibiotics.

Results

In all, 15,933 patients were treated with latanoprost and 7670 with travoprost-Z. Over 1 year, 4.3% of latanoprost and 4.5% of travoprost-Z patients were identified with dry eye (p = 0.28), and 10.9% and 11.1%, respectively, were identified with an ocular infection (p = 0.79). The 1-year incidence of new coding for ocular surface disease also was similar across treatments (13.9% vs 14.3%, respectively; p = 0.48).

Conclusions

The retrospective analysis of three large prescription databases revealed that open-angle glaucoma and ocular hypertension patients newly treated with latanoprost preserved with BAK or travoprost-Z preserved with SofZia did not differ statistically in rates of dry eye, ocular infection, or ocular surface disease (either dry eye or ocular infection) during the first year post-index. Claims-based analyses are limited by nonrandomization and the inability to account for over-the-counter use or samples.

Timogel® vs Timolol 0.5% Ophthalmic Solution: Efficacy, Safety, and Acceptance

Purpose

To evaluate the efficacy, safety, and tolerability of Timogel® preservative-free once daily compared to timolol 0.5% ophthalmic solution bid in patients with ocular hypertension (OHT) and patients with primary open-angle glaucoma (POAG).

Methods

A total of 75 patients with OHT and patients with POAG treated with timolol 0.5% bid with intraocular pressure (IOP) ≤21 mmHg were enrolled. They underwent complete ophthalmologic examination, IOP measurements (at trough and daytime curve), evaluation of side effects, Schirmer test, break-up time [BUT], blood pressure, heart rate, ocular diastolic perfusion pressure measurements, and acceptance (Comparison of Ophthalmic Medications for Tolerability). Patients switched to Timogel® and were re-evaluated 3 months later. The analysis of variance and the Pearson χ2 tests were used to test differences between the treatments.

Results

Intraocular pressure reduction at trough was 23.6% with timolol 0.5% and 22.3% with Timogel®. No statistical differences were observed in IOP values at trough and in the daytime curve between the 2 treatments. Local and systemic side effects were less frequent with Timogel® (hazard ratio: p<0.05). Patients demonstrated a significant improvement of Schirmer test and BUT (p<0.05) and a reduction of dryness and foreign body sensation (42.6% vs 15.4%; p<0.01) after switching to Timogel®. Mild and short-lasting blurred vision after Timogel® instillation occurred in about 18.5% of patients. A total of 82% of patients were satisfied or very satisfied with Timogel® vs 61% with previous treatment (p<0.01).

Conclusions

Timogel® preservative-free dosed once every morning has a 24-hour hypotensive effect with a better safety profile than timolol 0.5% bid and it is well-accepted by patients. The once-daily dosing improved acceptance and compliance.

Efficacy, safety, and improved tolerability of travoprost BAK-free ophthalmic solution compared with prior prostaglandin therapy

Purpose

To evaluate the efficacy, safety and tolerability of changing to travoprost BAK-free from prior prostaglandin therapy in patients with primary open-angle glaucoma or ocular hypertension.

Design

Prospective, multi-center, historical control study.

Methods

Patients treated with latanoprost or bimatoprost who needed alternative therapy due to tolerability issues were enrolled. Patients were surveyed using the Ocular Surface Disease Index (OSDI) to evaluate OSD symptoms prior to changing to travoprost BAK-free dosed once every evening. Patients were re-evaluated 3 months later.

Results

In 691 patients, travoprost BAK-free demonstrated improved mean OSDI scores compared to either latanoprost or bimatoprost (p < 0.0001). Patients having any baseline OSD symptoms (n = 235) demonstrated significant improvement after switching to travoprost BAK-free (p < 0.0001). In 70.2% of these patients, symptoms were reduced in severity by at least 1 level. After changing medications to travoprost BAK-free, mean intraocular pressure (IOP) was significantly decreased (p < 0.0001). Overall, 72.4% preferred travoprost BAK-free (p < 0.0001, travoprost BAK-free vs prior therapy). Travoprost BAK-free demonstrated less conjunctival hyperemia than either prior therapy (p < 0.0001).

Conclusions

Patients previously treated with a BAK-preserved prostaglandin analog who are changed to travoprost BAK-free have clinically and statistically significant improvement in their OSD symptoms, decreased hyperemia, and equal or better IOP control.

Switching patients from preserved prostaglandin-analog monotherapy to preservative-free tafluprost

Purpose:

Efficacy, tolerability and safety of the novel preservative-free prostaglandin tafluprost 0.0015% were investigated for the treatment of patients with glaucoma or ocular hypertension in a clinical setting.

Patients and methods:

Data were collected in a non-interventional, prospective, multi-center, observational, open label study. 118 patients were treated with a prostaglandin analog (PGA) monotherapy (preserved formulations of latanoprost, travoprost or bimatoprost) prior to baseline. Intraocular pressure (IOP) readings were recorded for each eye at baseline (previous therapy), 4–6 weeks, and 12 weeks after changing medical treatment to preservative-free tafluprost once-daily. We analyzed the change in IOP over the study period for all patients as well as for a subgroup of patients with prior PGA monotherapy. Subjective symptoms and objective ocular signs were determined. Comfort was measured using a 4 step scale. All adverse events were recorded. Paired t-tests were conducted to compare IOP values at baseline to IOP values after treatment with tafluprost 0.0015%. Bowker’s test of symmetry was used for statistical evaluation of changes of clinical signs (hyperemia).

Results:

In total 118 patients were eligible for evaluation. In these patients with prior PGA monotherapy (n = 118) IOP decreased significantly from 16.2 ± 4.3 mm Hg (95% CI: 0.55) at treated baseline to 14.8 ± 3.2 mm Hg (95% CI: 0.43; P < 0.001) at final visit on tafluprost. In a subset of patients with prior latanoprost monotherapy (n = 68) mean IOP at baseline (±SD) was reduced from 16.2 ± 4.6 mm Hg (95% CI: 0.77) 14.8 ± 3.1 mm Hg at final visit (95% CI: 0.54, P < 0.001), in patients with prior travoprost monotherapy (n = 32) from 16.2 ± 4.3 mm Hg (95% CI: 1.05) to 14.9 ± 3.3 mm Hg (95% CI: 0.91; P < 0.05) and in patients with prior bimatoprost monotherapy (n = 18) from 16.4 ± 3.5 mm Hg (95% CI: 1.14) to 15.0 ± 3.3 mm Hg (95% CI: 1.14; P = 0.252). Both, objective clinical signs and subjective symptoms improved after changing medication to preservative-free tafluprost until final visit. The number of patients with moderate and severe hyperemia decreased from 51 (43.2%) at baseline to 2 (1.9%) at final visit.

Conclusion:

Preservative-free tafluprost 0.0015% was effective, well tolerated and safe. IOP was controlled effectively and ocular symptoms and clinical signs were improved after changing medication to a monotherapy with preservative-free tafluprost in patients previously treated with a preserved latanoprost, travoprost or bimatoprost monotherapy.

Effects of benzalkonium chloride on the ocular surface of the rabbit

PURPOSE

To evaluate the effects of benzalkonium chloride (BAK) on the ocular surface in rabbits.

METHODS

Eighteen white rabbits were divided into three groups. Topical administration of eye drops was performed four times a day for 14 days; 0.01% BAK for group I, 0.1% BAK for group II, and phosphate-buffered saline (PBS) for the control group. Schirmer test and Rose Bengal staining were carried out and conjunctival impression cytology was performed in both the upper and lower bulbar conjunctiva on days 0, 7, and 14. After day 14, both the upper and lower conjunctiva were evaluated by light and electron microscopy. Immunofluorescence staining was also performed for the detection of mucin 5AC.

RESULTS

A decrease in the goblet cell density (GCD) and histopathological changes were more prominent in the BAK-treated groups compared to the control group (P < 0.05). Moreover, these changes were more noticeable in group II than in group I (P < 0.05). The decrease in the GCD and histopathological changes were statistically more significant in the lower conjunctiva than in the upper conjunctiva in the BAK-treated groups (P < 0.05).

CONCLUSION

BAK caused damage to the ocular surface in a gravity-dependent manner. The adverse effects of BAK were more severe in the lower conjunctiva than in the upper conjunctiva.

[Managing treatment side effects: the respective roles of the active ingredient and the preservative]

The side effects of glaucoma hypotensive treatments usually remain moderate and limited to local side effects - conjunctival hyperemia, itching, discomfort after instillation - but are very often a leading source of poor compliance to treatment and thereby may decrease its efficacy. Moreover, these symptoms usually reflect progressive and irreversible major ocular surface changes. These ocular surface changes induced by glaucoma eyedrops may include subconjunctival fibrosis, increasing the risk of failure of a further glaucoma surgery. All the components of the hypotensive eye drops, including the active ingredient, the preservatives, and the excipients, may be involved in the occurrence of these side effects. It is therefore important to identify the agents involved and the mechanisms of these side effects, in order to choose a treatment minimizing their risk and the discomfort felt by patients, and therefore increasing the likelihood of good compliance. When available, preservative-free solutions should be considered.

Current and emerging medical therapies in the treatment of glaucoma

INTRODUCTION

Glaucoma is a disease of the eye in which the optic nerve and retinal ganglion cells (RGCs) are injured, leading to the loss of the peripheral visual field and eventually to profound vision loss and blindness. Glaucoma is usually characterized by an increase in intraocular pressure (IOP), which is treated with ocular hypotensive drugs. However, both RGC apoptosis and optic nerve atrophy, due to glaucoma, can occur independently of IOP.

AREAS COVERED

This review discusses several current and emerging treatments for glaucoma. Current research is updating the known properties of a number of drugs now used to treat glaucoma. Some drugs may offer neuroprotection, not only reducing vision loss, but restoring injured or compromised RGCs and optic nerve cells. Several molecules now under development aim to lower IOP primarily by enhancing aqueous drainage through conventional pathways of the trabecular meshwork and Schlemm's canal. Gene transfer models are being investigated, and a murine-derived neurotrophic growth factor (NGF) seems to offer the promise of actually restoring visual function in some patients. Drugs that are already widely used are being re-branded in preservative-free formulations.

EXPERT OPINION

The ultimate goal in glaucoma research is to find new compounds that will not only normalize IOP, but also arrest or even reverse apoptotic damage to the optic nerve and RGCs to slow the rate of progression of the disease so that it will not interfere with the patient's ability to see and his/her quality of life. This should be obtained with affordable costs, minimal side effects and a reasonable schedule.

[Ocular toxicity of benzalkonium]

In order to meet the requirements of the pharmacopeia, ophthalmic preparations have to be manufactured in conditions that can secure their sterility before use and can prevent the development of micro-organisms after opening of the vial. The addition of an appropriate preservative is a way to meet this requirement. However, in addition to their lack of efficacy in certain conditions, they can be problematic in terms of formulation, stability and interaction with the packagings. Furthermore, their daily and repeated use in chronic pathologies such as glaucoma, dry eye or allergy has revealed their nuisance. Moreover, the recognition of certain parameters such as life quality and therapeutic observance has strengthened the proofs that have already been clinically shown. The review of the experimental and clinical data already published about the toxicity of the preservatives shows that almost every ocular structure is affected to various extents. From the first assumption data to preclinical and clinical proofs, this article highlights the evolution of the understanding process towards the toxic role of preservatives.

Focusing on glaucoma progression and the clinical importance of progression rate measurement: a review

PURPOSE

This review aims to provide guidance in managing glaucoma patients more effectively. It focuses on the importance of detecting progression and measuring its rate within the management of primary open-angle glaucoma today. Recent findings strongly indicate that continued monitoring of visual fields (VFs) and reassessment of target intraocular pressures (IOPs) depending on VF progression rates are mandatory in the management of glaucoma.

METHODS

Data on glaucoma progression from older as well as most recent literature findings are summarized in this article. In addition, the article elaborates on the scientific content from a series of lectures given by experts in the field during several international symposia on 'rate of progression' in 2008.

RESULTS

This review summarizes key findings on the natural history of glaucoma and known factors for disease progression. It highlights the visual function changes observed as glaucoma progresses and discusses disease impact on patients' quality of life. Findings support the need to obtain information on rate of progression and its importance for clinical management. Practical ways to measure rate of progression are given by new software options to help measure major parameters. Finally, on the basis of a patient's individual rate of progression therapeutic options are assessed, such as maximum medical therapy with fixed combinations.

CONCLUSIONS

Estimating a patient's individual rate of VF progression by using newly developed analyses will be helpful to forecast the potential future development of the glaucoma. An individualized treatment approach then requires that in patients in whom the risk of becoming visually impaired or blind during their lifetime is higher, a more intensive medical IOP-lowering therapy such as fixed combinations can be considered as treatment option.