Toxicological evaluation of preservative-containing and preservative-free topical prostaglandin analogues on a three-dimensional-reconstituted corneal epithelium system

Multiple use of preservative-free single dose unit dexamethasone 0.1% eye drops is safe within 24 hours

BACKGROUND

Unpreserved single-dose unit (SDU) eye drops are commonly used to avoid benzalkonium chloride-related toxicity. Although intended for single use, many patients report off-label repeated use of SDUs over a prolonged period. We investigated whether repeated use of dexamethasone 0.1% SDUs in the same patient increases the bacterial contamination rate.

METHODS

We prospectively enrolled patients scheduled for inpatient corneal and glaucoma surgery receiving dexamethasone 0.1% SDU four times per day from the same vial. To assess contamination rates, one drop from the vial was cultured immediately after opening the SDU (t0), 10 hours later after four drop applications (t10) and 24 hours after opening without further drop applications (t24). Conjunctival swabs were taken before and after drop application. Contamination rate was assessed with a standard clinical culturing protocol without introducing a positive control.

RESULTS

110 eyes of 109 patients were evaluated. Drops collected immediately after opening the SDU (t0) were contaminated in 9/110 cultures (8.1%). At t10, 13/110 cultures were contaminated (11.8%; p=0.267) and 11/110 at t24 (10.0%; t24 vs t0; p=1.00). In 5 of 21 cases of contaminated drops at t10 and/or t24, the same isolates were cultured from the initial conjunctival swab and the SDU. In three cases, the same bacterial species was found in consecutive samples.

CONCLUSION

The contamination rate of the SDU did not increase after multiple use within 24 hours. Contamination from fingertip flora was more likely than from ocular surface flora. Reuse of dexamethasone 0.1% SDU in the same patient within 24 hours appears to be safe.

From Eye Care to Hair Growth: Bimatoprost

BACKGROUND

Bimatoprost has emerged as a significant medication in the field of medicine over the past several decades, with diverse applications in ophthalmology, dermatology, and beyond. Originally developed as an ocular hypotensive agent, it has proven highly effective in treating glaucoma and ocular hypertension. Its ability to reduce intraocular pressure has established it as a first-line treatment option, improving management and preventing vision loss. In dermatology, bimatoprost has shown promising results in the promotion of hair growth, particularly in the treatment of alopecia and hypotrichosis. Its mechanism of action, stimulating the hair cycle and prolonging the growth phase, has led to the development of bimatoprost-containing solutions for enhancing eyelash growth.

AIM

The aim of our review is to provide a brief description, overview, and studies in the current literature regarding the versatile clinical use of bimatoprost in recent years. This can help clinicians determine the most suitable individualized therapy to meet the needs of each patient.

METHODS

Our methods involve a comprehensive review of the latest advancements reported in the literature in bimatoprost formulations, which range from traditional eye drops to sustained-release implants. These innovations offer extended drug delivery, enhance patient compliance, and minimize side effects.

RESULTS

The vast literature published on PubMed has confirmed the clinical usefulness of bimatoprost in lowering intraocular pressure and in managing patients with glaucoma. Numerous studies have shown promising results in dermatology and esthetics in promoting hair growth, particularly in treating alopecia and hypotrichosis. Its mechanism of action involves stimulating the hair cycle and prolonging the growth phase, leading to the development of solutions that enhance eyelash growth. The global use of bimatoprost has expanded significantly, with applications growing beyond its initial indications. Ongoing research is exploring its potential in glaucoma surgery, neuroprotection, and cosmetic procedures.

CONCLUSIONS

Bimatoprost has shown immense potential for addressing a wide range of therapeutic needs through various formulations and advancements. Promising future perspectives include the exploration of novel delivery systems such as contact lenses and microneedles to further enhance drug efficacy and patient comfort. Ongoing research and future perspectives continue to shape its role in medicine, promising further advancements and improved patient outcomes.

[Three-component tear substitute as preoperative support in glaucoma surgery]

PURPOSE

This study investigates the effect of preoperative preparation with the three-component tear substitute Stillavit on the outcomes of glaucoma surgery in patients on long-term topical glaucoma therapy.

MATERIAL AND METHODS

The study included 63 patients (63 eyes) with glaucoma, among them 30 (30 eyes) were women and 33 (33 eyes) were men. Group 1 consisted of 33 patients (33 eyes) receiving long-term topical antihypertensive therapy with preservatives and tear substitute Stillavit 3 times a day for 1 month as preoperative preparation. Group 2 included 30 patients (30 eyes) receiving similar antihypertensive therapy who were not prescribed preoperative medications. All patients underwent a comprehensive ophthalmological examination and computer tomography of the filtering blebs (FB) on Visante system (Carl Zeiss Meditec, Germany) before surgery, as well as 1 week, 1, 3, and 6 months after surgery.

RESULTS

Mean intraocular pressure (IOP) elevation at 6 months postoperatively was significantly higher in the group that did not undergo preoperative preparation with a tear substitute, compared to the group of patients who received the tear substitute Stillavit preoperatively. According to anterior segment optical coherence tomography, a greater number of favorable diffuse FB were noted in the group that received the tear substitute Stillavit in preparation for surgery - 87.9%, while in group 2 (without preparation) - 66.7%. Odds ratio calculation between the two groups revealed that preoperative preparation with the tear substitute Stillavit reduced the odds of IOP elevation to 20 mm Hg or higher at 3 months postoperatively by more than 10 times.

CONCLUSION

The use of tear substitute Stillavit in preparation for anti-glaucoma surgery reduces the chances of IOP elevation in the early postoperative period by more than 10 times, which may indicate a reduction in the rate of FB scarring due to the beneficial effect of the drug's components on the precorneal tear film.

Tafluprost promotes axon regeneration after optic nerve crush via Zn2+-mTOR pathway

PURPOSE

To investigate whether Tafluprost could promote optic nerve regeneration in mice after optic nerve crush (ONC) and determine the underlying molecular mechanism.

METHODS

Tafluprost was injected into the vitreous body immediately after ONC. The level of Zn2+ in the inner plexiform layer (IPL) of the retina was stained using autometallography (AMG). The number of survival retinal ganglion cells (RGCs) was determined via dual staining with RGC markers Tuj1 and RBPMS. Individual axons that regenerated to 0.25, 0.5, 0.75 and 1 mm were manually counted in the whole-mount optic nerve labeled by cholera toxin B fragment (CTB). Immunofluorescence and Western blot were performed to detect protein expression levels. Pattern electroretinogram was used to evaluate RGCs function.

RESULTS

Tafluprost promoted RGC survival in a dose-dependent manner with an optimal concentration of 1 μM. Tafluprost significantly decreased ZnT-3 expression and Zn2+ accumulation in the IPL of retina. Tafluprost stimulated intense axonal regeneration and maintained RGCs function compared to control. Mechanistically, Tafluprost and Zn2+ elimination treatment (TPEN or ZnT-3 deletion) can activate the mTOR pathway with an improved percentage of pS6+ RGCs in the retina. However, rapamycin, a specific inhibitor of the mTOR1, inhibited the activation of the mTOR pathway and abolished the regenerative effect mediated by Tafluprost. Tafluprost also inhibited the upregulation of p62, LC3 and Beclin-1, attenuated the overactivation of microglia/macrophages and downregulated the expression of TNFα and IL-1β.

CONCLUSIONS

Our results suggest that Tafluprost promoted axon regeneration via regulation of the Zn2+-mTOR pathway, and provide novel research directions for glaucomatous optic nerve injury mechanisms.

The use of benzalkonium chloride in topical glaucoma treatment: An investigation of the efficacy and safety of benzalkonium chloride-preserved intraocular pressure-lowering eye drops and their effect on conjunctival goblet cells

ENGLISH SUMMARY

Glaucoma is a leading cause of the global prevalence of irreversible blindness. The pathogenesis of glaucoma is not entirely known, but the major risk factors include advancing age, genetic predisposition, and increased intraocular pressure (IOP). The only evidence-based treatment is a lowering of IOP through the use of eye drops, laser procedures, or surgical interventions. Although laser treatment is gaining recognition as a first-choice treatment option, the most common approach for managing glaucoma is IOP-lowering eye drops. A major challenge in the treatment is the occurrence of adverse events and poor adherence. In this context, the ocular surface is an area of great concern, as most glaucoma patients have dry eye disease (DED), which is largely caused by eye drops. Preservation with benzalkonium chloride (BAK) is a controversial topic due to its potential role as a significant cause of DED. A systematic review and meta-analyses investigate potential differences in efficacy and safety between BAK-preserved and BAK-free anti-glaucomatous eye drops (I). Many of the included studies report on ocular surface damage caused by the application of BAK-preserved eye drops. However, the meta-analyses addressing hyperemia, number of ocular adverse events, and tear break-up time did not identify any significant differences. The latter is likely due to varying measurement methods, different endpoints, and study durations. It is, therefore, possible that the large variations between the studies conceal differences in the safety profiles. The efficacy meta-analysis finds that there are no differences in the IOP-lowering effect between BAK-preserved and BAK-free eye drops, indicating that BAK is not necessary for the effectiveness of eye drops. To promote more homogeneous choices of endpoints and methods when evaluating BAK-preserved and BAK-free glaucoma treatments, a Delphi consensus statement was performed. In this study, glaucoma experts and ocular surface disease experts reached consensus on the key factors to consider when designing such studies (II). The hope is to have more studies with comparable endpoints that can systematically show the potentially adverse effects of BAK. The preclinical studies in the current Ph.D. research focus on conjunctival goblet cells (GCs). GCs are important for the ocular surface because they release the mucin MUC5AC, which is an essential component of the inner layer of the tear film. BAK preservation may damage the GCs and result in a low GC density, leading to an unstable tear film and DED. The most commonly used IOP-lowering drugs are prostaglandin analogs (PGAs). Thus, the conducted studies investigate the effect of PGAs preserved in different ways on GCs. BAK-preserved latanoprost is cytotoxic to primary cultured human conjunctival GCs and results in a scattered expression of MUC5AC, in contrast to negative controls, where MUC5AC is localized around the cell nucleus (III). Preservative-free (PF) latanoprost is not cytotoxic and does not affect the MUC5AC expression pattern. Furthermore, BAK-preserved travoprost is found to be cytotoxic in a time-dependent manner, while Polyquad®-preserved travoprost does not affect GC survival at any measured time point (IV). Both Polyquad and BAK induce scattered expression of MUC5AC. The cytotoxicity of BAK-preserved PGA eye drops is higher compared to the safer profile of PF and Polyquad-preserved PGA eye drops (V). Additionally, PF latanoprost does not increase the release of the inflammatory markers interleukin (IL)-6 and IL-8, unlike BAK-preserved latanoprost. A review highlights the active and inactive components of IOP-lowering eye drops (VI). Several preclinical and clinical studies have identified adverse effects of BAK. Although other components, such as the active drug and phosphates, can also cause adverse events, the review clearly states that BAK alone is a major source of decreased tolerability. The conclusion of this thesis is that BAK preservation is unnecessary and harmful to the ocular surface. The preclinical studies demonstrate that GCs die when exposed to BAK. Furthermore, they find that BAK induces a pro-inflammatory response. The review included in the thesis concludes that BAK should be phased out of eye drops for chronic use. Overall, the inclusion of BAK poses a risk of developing DED and poor adherence, which can ultimately lead to disease progression and blindness.

Pharmacokinetic and Ocular Toxicity Evaluation of Latanoprost Ophthalmic Solution, 0.005%, with Preservative Level Reduced to Below the Limit of Quantitation

Purpose: The systemic and ocular pharmacokinetics (PK), and ocular toxicity of benzalkonium chloride (BAK)-free TearClear latanoprost ophthalmic solution, 0.005% formulation (TC-002) were evaluated. TC-002 is designed to selectively capture BAK at the time of drug administration; therefore, the dose delivered to the eye contains no quantifiable level of preservative. Methods: The systemic and ocular PK of TC-002 were compared to a BAK containing reference listed drug (RLD, Xalatan™) over a 24-h period, after a single topical ocular dose to 1 eye of male Dutch Belted (DB) rabbits (n = 3/timepoint). Latanoprost acid concentrations were measured in plasma and ocular tissues. The ocular toxicity was evaluated in a separate study and included toxicokinetic evaluation of TC-002 after once daily topical ocular dosing into each eye of DB rabbits (n = 8/group) for at least 28 days. Toxicity endpoints included ophthalmic and clinical evaluations, necropsy, and microscopic evaluation of ocular tissues. Results: Average ratios of Cmax values for TC-002/RLD ranged from 0.6 to 1.6, and Cmax and area under the concentration-time curve of last observed concentration (AUClast) exposures to latanoprost acid were similar (<2-fold) between the 2 treatments. In the 28-day study, the Tmax was achieved in both groups in <0.5 h. There were no abnormal ocular findings. Conclusions: TC-002 with no quantifiable preservative or BAK-containing RLD exhibited similar ocular and systemic PK profiles. TC-002 was well tolerated and comparable to RLD. TC-002 retains the safety and PK characteristics of RLD without the added concern of long-term exposure of the eye to preservatives.

Comparison of cytotoxic, apoptotic and oxidative properties of Akacid plus and chlorhexidine in corneal epithelial cell culture

PURPOSE

This study aims to compare the cytotoxic, apoptotic, and oxidative effects of a new cationic disinfectant, Akacid Plus, with chlorhexidine, on the human corneal epithelial cell line.

METHODS

Time-dependent cytotoxicity studies were performed with the Alamar Blue method. Apoptotic activity was investigated by flow cytometric methods. Reactive oxygen species levels were measured with the ROS cellular test kit. BAX, BCL2 and caspase 3, 9, 12 mRNA expressions were evaluated by PCR, as well as BAX and BCL2 protein expressions by Western-Blot.

RESULTS

At the fifth minute of the treatment, the viability was 68.15% with Akacid Plus and 43.95% with chlorhexidine. At the 15th minute, no significant difference was observed with both solutions. In the apoptotic evaluation, Akacid Plus significantly increased the early and late apoptotic activity in the cell line (p < 0.0001), while a significant increase was observed in late apoptosis and necrosis levels with chlorhexidine (p < 0.001). Chlorhexidine also induced gene expression of BAX, BCL2, caspase 3, 9 and BAX proteins (p < 0.05), while reducing protein expression of BCL2 (p < 0.001). Akacid Plus induced the gene expressions of BCL2, CASP3 and caspase 9, reduced gene expressions of BAX and caspase 12 and protein expression of BCL2 (p < 0.05). No significant difference was observed in the ROS level with both solutions (p > 0.05).

CONCLUSION

Due to the widespread use of cationic polymers in ophthalmology, this new molecule with high antimicrobial activity and relatively low cytotoxicity may be of interest for clinical use. Further investigations are necessary to fully understand the ophthalmologic potential of this solution.

The molecular aspect of anti-glaucomatous eye drops - are we harming our patients?

Glaucoma is one of the leading causes of irreversible blindness. Progression is halted with a reduction in intraocular pressure (IOP), which is most often achieved with eye drops. A major challenge in the topical treatment of glaucoma patients is the many side effects and the resulting reduced adherence. Side effects may of course be due to the molecular properties of the active pharmaceutical ingredients (APIs). There are currently six different APIs available: prostaglandin analogues, β-adrenergic inhibitors, α-adrenergic agonists, carbonic anhydrase inhibitors, rho-kinase inhibitors and muscarinic 3 agonists. But the additives used in eye drops are also known to cause damage to the ocular surface and to some extent also to the deeper tissues. Said additives are considered inactive molecular components and are added to secure for instance viscosity and pH value, and to prevent contamination. There has been an increasing focus on the harmful effects of preservatives, with the most commonly used preservative benzalkonium chloride (BAK) being particularly controversial. BAK has long been recognized as a toxin that increases the risk of ocular discomfort. This can affect the adherence and ultimately result in lack of disease control. Other issues include the addition of certain buffers, such as phosphates, and varying pH values. This review will address the different molecular components of the IOP-lowering eye drops and what to be aware of when prescribing topical glaucoma treatment.

Impact of Latanoprost Antiglaucoma Eyedrops and Their Excipients on Toxicity and Healing Characteristics in the Ex Vivo Eye Irritation Test System

INTRODUCTION

Corneal epithelial toxicity and delayed healing process have already been attributed to preservatives or some excipients. We study the effects of galenic components in antiglaucoma drugs such as benzalkonium chloride (BAC) or surfactants like macrogolglycerol hydroxystearate 40 (MGHS 40) on corneal toxicity in an ex vivo system mimicking chronic use.

METHODS

Latanoprost-containing eyedrops are available with and without preservatives on the market. Unpreserved, they are available in different formulations with various excipients like MGHS at different concentrations (0%, 2.5%, and 5%). We studied these in the ex vivo bioreactor (EVEIT) on initially injured rabbit corneas. The drugs were applied six times daily for observation periods of 3 or 5 days. BAC, 5% MGHS 40 solution, and 0.18% hyaluronic acid served as controls. Macroscopic photographic, biochemical methods and corneal integrity quantification were used for evaluation. Toxicity was assessed by measuring wound healing and corneal fluorescein sodium permeability and was confirmed by histology studies.

RESULTS

The BAC-preserved formulation resulted in high corneal toxicity, which was expected. Interestingly, the preservative-free (PF) formulation containing 5% MGHS 40, carbomer, macrogol 4000, and sorbitol showed the highest corneal toxicity, followed by the control formulation with equal MGHS 40 concentration, which presented significantly less damage. No toxicity was shown by eyedrops containing 2.5% MGHS 40 or salts only.

CONCLUSION

Our study demonstrates a significant corneal toxicity of certain formulations of PF antiglaucoma ophthalmic drugs containing 5% MGHS 40 with other excipients compared to other formulations with lower MGHS 40 concentrations (2.5% or 0%), or even compared to the solution containing 5% MGHS alone. This suggests a concentration-dependent toxicity of MGHS 40, especially in interaction with other excipients, which may increase its epithelial toxicity, and that has to be considered in clinical glaucoma therapy. Further single-component formulation trials are needed to support this interpretation.

TFOS Lifestyle: Impact of elective medications and procedures on the ocular surface

The word "elective" refers to medications and procedures undertaken by choice or with a lower grade of prioritization. Patients usually use elective medications or undergo elective procedures to treat pathologic conditions or for cosmetic enhancement, impacting their lifestyle positively and, thus, improving their quality of life. However, those interventions can affect the homeostasis of the tear film and ocular surface. Consequently, they generate signs and symptoms that could impair the patient's quality of life. This report describes the impact of elective topical and systemic medications and procedures on the ocular surface and the underlying mechanisms. Moreover, elective procedures performed for ocular diseases, cosmetic enhancement, and non-ophthalmic interventions, such as radiotherapy and bariatric surgery, are discussed. The report also evaluates significant anatomical and biological consequences of non-urgent interventions to the ocular surface, such as neuropathic and neurotrophic keratopathies. Besides that, it provides an overview of the prophylaxis and management of pathological conditions resulting from the studied interventions and suggests areas for future research. The report also contains a systematic review investigating the quality of life among people who have undergone small incision lenticule extraction (SMILE). Overall, SMILE refractive surgery seems to cause more vision disturbances than LASIK in the first month post-surgery, but less dry eye symptoms in long-term follow up.

Ocular surface disease signs and symptoms of glaucoma patients and their relation to glaucoma medication in Finland

PURPOSE

To evaluate the prevalence of ocular surface disease (OSD) signs and symptoms of glaucoma patients in private clinics in relation to topical glaucoma treatment and to compare them to non-glaucomatous population.

METHODS

A multicenter, cross-sectional study consisting of private ophthalmology clinic visits in southern Finland. Glaucoma patients had a diagnosis of primary open-angle glaucoma, pseudoexfoliation glaucoma, pigmentary glaucoma, or treated ocular hypertension. Control patients had no prior or current use of glaucoma medication. Recorded parameters included OSD signs and symptoms, used glaucoma medications during the past 6 months, and the product name, type, and duration of used antiglaucoma drugs.

RESULTS

Glaucoma patients (n = 564) showed higher severity of OSD sign parameters excluding Schirmer's test, as well as increased dry eye sensation compared to controls (n = 51). Beta-blockers and preservative-free prostaglandins had the smallest effect on all parameters. The increasing number of active compounds and administered eye drops per day showed an association with increasing severity of OSD signs, as well as dry eye and foreign body sensation. Duration of glaucoma medication showed no significant association with OSD signs or symptoms.

CONCLUSION

Glaucoma patients show higher prevalence of OSD signs and dry eye sensation compared to non-glaucomatous population. The use of preserved glaucoma medication, as well as high number of active compounds and eye drops increase the severity of these parameters. There are significant differences between the types of glaucoma medication used, and therefore the selection of them is important especially in patients suffering from OSD.

Cytotoxic, Apoptotic, and Oxidative Effects of Preserved and Preservative-Free Brimonidine in a Corneal Epithelial Cell Line

Purpose: This study aims to compare the cytotoxic, apoptotic, and oxidative effects of preserved and preservative-free forms of brimonidine 0.15% on the human corneal epithelial cell (HCEC) line. Methods: Time-dependent cytotoxicity studies were performed with the Alamar Blue method. For apoptotic studies, PE Annexin V and 7-amino-actinomycin (7-AAD) staining and flow cytometry were performed. Messenger RNA (mRNA) expressions of Bax, Bcl-2, and caspase-3, -9, -12, and protein expressions of Bax and Bcl-2 were evaluated by quantitative real-time polymerase chain reaction and Western blot method, respectively. Results: Cell viability was 76.4% with the preserved solution and 36.05% with the preservative-free solution at the fifth minute. No significant difference was observed with either solution at the 15-min mark, whereas cell viability did not change significantly after 1 h. In the apoptosis evaluation, it was observed that the preservative-free solution increased the early apoptotic activity to a greater degree (P < 0.05). Preservative-free solution also induced gene expression of proapoptotic Bax, caspase-9 and -12, and protein expression of Bax while reducing the protein expression of anti-apoptotic Bcl-2 (P < 0.0001). Preserved solution induced only the gene expression of caspase-12, and reduced the protein expression of Bcl-2 (P < 0.0001). No significant difference was observed in the reactive oxygen species (ROS) levels of either solution compared with the control group (P > 0.05). Conclusion: It was demonstrated that the preserved solution is less cytotoxic to the HCEC line in the early period, has less early apoptotic activity, and does not significantly increase ROS levels.

A Narrative Review of Ocular Surface Disease Related to Anti-Glaucomatous Medications

Topical anti-glaucomatous medications are still the most important measure to lower intraocular pressure. Large number of studies have confirmed that long-term use of anti-glaucomatous eye drops, especially containing benzalkonium chloride, a preservative, can cause or aggravate ocular surface injury. Ocular surface diseases damage the ocular microenvironmental health status, reduce the patients’ compliance with the treatment, and finally affect the treatment result. Therefore, the ocular surface management of patients with glaucoma is very important. This includes the selection of drugs that are better tolerated according to individual conditions, preservative-free formulations, drugs that protect against ocular surface disease, or selecting surgery and laser treatment, to prevent the damage to the ocular surface by topical anti-glaucomatous drugs.

Comparison of Topical Instillation From Single-dose and Multidose Eye Drop Containers in Glaucoma: A Multicenter Randomized Cross-sectional Trial

PRECIS

We compared the quality of instillation of topical treatments from single-dose (SGD) or multidose (MTD) containers in glaucoma patients and showed neither a significant difference between the type of container nor a significant relationship to upper limb mobility.

PURPOSE

To describe and compare the quality of instillation of topical treatments with SGD or MTD containers in glaucoma patients. To assess factors likely to influence instillation, particularly the upper limb mobility.

MATERIALS AND METHODS

This multicenter, cross-sectional study included open-angle glaucoma patients with the same self-instilled treatment over at least 3 months. Patients were asked to successively self-administer a drop of artificial tears from SGD and MTD containers in front of an observer. The order of instillation (eye and container) was randomized. Correct instillation was defined as the administration of 1 drop in the lower fornix, without any contact between the tip of the device and the ocular surface. The Quick Disabilities of the Arm, Shoulder, and Hand self-questionnaire assessed upper limb mobility.

RESULTS

A total of 239 eyes from 173 patients were included. For the worst eye group 33% of patients performed correct instillation with MTD versus 32% using SGD (P=1). In the best eye group, 31.7% patients performed a correct instillation with MTD administration versus 27.5% with SGD (P=0.327). Multivariate analysis showed a significant association between an inadequate SGD instillation, old age (P=0.021), the severity of the visual field deficits (P=0.035), and a low quality of life score (P=0.028). No association existed between the Quick Disabilities of the Arm, Shoulder, and Hand score and the quality of instillation.

CONCLUSIONS

These results suggest that the handling of single-use containers should be practiced by patients and evaluated by physicians, especially for the elderly population and those with advanced glaucoma. No difference in instillation quality was found between SGD and MTD.

Intraocular Pressure Reduction Effect of 0.005% Latanoprost Eye Drops in a Hyaluronic Acid-Chitosan Nanoparticle Drug Delivery System in Albino Rabbits

Purpose

The purpose of this study was to evaluate the intraocular pressure (IOP) reduction efficiency of hyaluronic acid-chitosan-latanoprost link nanoparticle (HA-CS-latanoprost link NP) formulated eye drops.

Methods

The IOP reduction study was performed in 24 normotensive albino rabbits. The test animals were randomized and grouped accordingly to treatment namely, HA-CS-latanoprost link NP, plain latanoprost, and the commercially available Xalatan eye drop, all were formulated with 0.005% latanoprost. The 9 days of the experiment were divided into baseline period (days 1-2), treatment period (days 3-6), and recovery period (days 7-9). A wireless noncontact tonometer was used to measure IOP at a time interval of 2 hours for 12 hours per day with 5 readings each.

Results

The highest mean daily IOP reduction during the treatment period was 24% for plain latanoprost, 23% for Xalatan, and 29% for HA-CS-latanoprost link NP. The maximum reduction in IOP for plain latanoprost and Xalatan all occurred at the sixth hour with the peak effects of 4.85 mm Hg (37%) and 4.8 mm Hg (36%), respectively. Although HA-CS-latanoprost link NP had peak effects of 5.75 mm Hg (43%) at the sixth hour and 5.22 mm Hg (39%) at the eighth hour. Daily mean IOP measurements of each treatment group showed that HA-CS-latanoprost link NP has a greater IOP reduction effect compared with the other two treatments (P < 0.001).

Conclusions

The results showed that the formulation of latanoprost with CS and HA is more effective in reducing the IOP than by drug alone.

Translational Relevance

The results provide evidence from animal experiment that HA-CS-latanoprost link NP formulation could improve and sustain drug concentration in the anterior segment of the eye. The improved reduction in IOP with that HA-CS-latanoprost link NP formulation can serve as a basis that latanoprost eye drops can be formulated with decreased concentration of benzalkonium HCl, an irritant preservative and penetration enhancer.

[Glaucoma surgery today]

BACKGROUND

The main goals of glaucoma treatment are to preserve the visual function and maintain as high a quality of life as possible at a cost acceptable to society. Therefore, it is crucial to carefully observe each individual patient in order to determine an individual and personalized treatment approach.

MATERIAL AND METHODS

This article summarizes the advantages and disadvantages of medicinal glaucoma treatment as well as traditional methods of glaucoma surgery, based on the current state of knowledge. The article explains the various mechanisms of action of new minimally invasive procedures, introduces the methods mostly commonly used in Germany and gives recommendations for preoperative care and postoperative follow-up.

RESULTS/CONCLUSION

In addition to the plethora of medicinal glaucoma treatments and classical surgical procedures, new minimally invasive treatment alternatives have become available in the past few years. The latter are an option for an earlier surgical intervention, especially in naïve or previously treated patients who appear to be unsuitable for medicinal treatment.

Self-assembled DNA nanoparticles loaded with travoprost for glaucoma-treatment

Lipid DNA nanoparticles (NPs) exhibit an intrinsic affinity to the ocular surface and can be loaded by hybridization with fluorophore-DNA conjugates or with the anti-glaucoma drug travoprost by hybridizing an aptamer that binds the medication. In the travoprost-loaded NPs (Trav-NPs), the drug is bound by specific, non-covalent interactions, not requiring any chemical modification of the active pharmaceutical ingredient. Fluorescently labeled Trav-NPs show a long-lasting adherence to the eye, up to sixty minutes after eye drop instillation. Biosafety of the Trav-NPs was proved and in vivo. Ex vivo and in vivo quantification of travoprost via LC-MS revealed that Trav-NPs deliver at least twice the amount of the drug at every time-point investigated compared to the pristine drug. The data successfully show the applicability of a DNA-based drug delivery system in the field of ophthalmology for the treatment of a major retinal eye disease, i.e. glaucoma.

Evaluation of ocular surface disease in elderly patients with glaucoma: expression of matrix metalloproteinase-9 in tears

PURPOSE

To evaluate the symptoms and signs of ocular surface disease (OSD) and tear-film matrix metalloproteinase-9 (MMP-9) overexpression using point-of-care testing (InflammaDry test) in patients with primary open-angle glaucoma (POAG).

METHODS

This prospective, case-control study included 67 patients diagnosed with POAG and 47 healthy control subjects. The OSD assessment included Schirmer-I test, the Oxford corneal stain scale, tear breakup time (TBUT), and the five-item dry eye questionnaire (DEQ-5). Measurement of extracellular MMP-9 level was performed using the InflammaDry test. The OSD parameters and MMP-9 expression levels were compared between the POAG group and the control group. Additional subgroup analysis in POAG group was performed according to number of topical glaucoma medications (Bottle 1, 2, or 3 medications).

RESULTS

There were significant differences between the control and POAG groups for all OSD parameters. MMP-9 overexpression was observed in 71.6% of POAG group, whereas only 31.9% of control group showed MMP-9 overexpression. The subgroup analysis revealed that DEQ-5, Oxford stain score, Schirmer-I, and MMP-9 overexpression demonstrated no significant difference among the three groups. Abnormal TBUT (≤5 s) was observed in 37.5%, 59.1%, and 76.2% for each subgroup according to number of bottles (1, 2, and 3), and strong MMP-9 overexpression were also detected in 25.0%, 40.9%, and 61.9%, respectively (P = 0.032, P = 0.043).

CONCLUSIONS

The use of preservative-containing medications may affect the ocular surface in patients with POAG. Graded measurement of tear-film MMP-9 could provide more information on OSD and might be a more useful marker for inflammation than then conventional results obtained by using an MMP-9 kit.

Toxicity profiles of fixed-combination eye drops for glaucoma therapy using cultivated human corneal epithelial sheets

PURPOSE

We aimed to investigate the toxicity of 6 fixed-combination drugs for glaucoma therapy using human corneal epithelial sheets (HCES).

STUDY DESIGN

Experimental.

MATERIALS AND METHODS

We used 6 kinds of commercially available fixed-combination drugs: latanoprost/carteolol (LAT/CAR), latanoprost/timolol (LAT/TIM), tafluprost/timolol (TAF/TIM), travoprost/timolol (TRA/TIM), brinzolamide/timolol (BRZ/TIM), and dorzolamide/timolol (DRZ/TIM) including different preservatives. The cell viability and barrier function of the HCES after exposure to the eye drops for 10 or 30 minutes were assessed using the WST-1 assay and transepithelial electrical resistance (TEER) measurements, respectively. The HCES were also evaluated using hematoxylin and eosin (HE) staining and transmission electron microscopy.

RESULTS

The cell viability significantly decreased in the HCES treated with LAT/TIM or DRZ/TIM after 10 and 30 minutes and in those treated with BRZ/TIM after 30 minutes. The barrier function increased significantly in the HCES treated with LAT/CAR. Histologically, the HCES were damaged after treatment with LAT/TIM, BRZ/TIM, or DRZ/TIM for 30 minutes. Transmission electron microscopy indicated narrow intercellular spaces and multiple intercellular junctions in the HCES treated with LAT/CAR, TAF/TIM, or TRA/TIM. The HCES treated with DRZ/TIM, BRZ/TIM, or LAT/TIM contained cytoplasmic vacuoles and collapsed cellular structures.

CONCLUSION

Glaucoma fixed-combination eye drops demonstrated a different toxic effect on the cell viability, barrier function, and morphologic changes of HCES.

Corneal damage and its recovery after instillation of preservative-free versus preserved latanoprost eye drops

Purpose: Latanoprost ophthalmic solution is highly effective as a therapeutic agent for glaucoma and is applied worldwide. However, harmful effects on the corneal surface have been reported regarding the commercially available latanoprost ophthalmic solution. Corneal surface toxicity may be caused by the added preservative of the ophthalmic solution. In order to ascertain whether latanoprost itself can damage the cornea or if this is solely due to the added preservatives, this study attempted to determine the corneal changes that occur at different time periods following usage of preservative-free versus preserved latanoprost eye drops.Materials and methods: Preservative-free latanoprost eye drops (Monoprost^®) or preserved latanoprost eye drops (Xalatan^®) containing 0.02% benzalkonium chloride (BAC) were instilled in the corneas of rabbits. For each of the two different eye drop solutions, the rabbits used in this experiment were divided into three exposure groups: 1 minute, 24 hour, and 1 week groups. Corneal transepithelial electrical resistance (TER) and scanning electron microscopy (SEM) were examined immediately (1 minute) after instillation, at 24 hours after instillation, and at 24 hours after 1 week of daily instillations of latanoprost. Hank's balanced salt solution was used in the control group.Results: The mean corneal TER of the control group was 933.8 ± 279.0 Ω cm². In preservative-free latanoprost instilled corneas, there was no significant decrease in the TER or morphological changes at any of the time points, with the relative TER values of 117 ± 38%, 100 ± 34%, and 93 ± 21% for 1 minute, 1 day, and 1 week time points, respectively. In preserved latanoprost instilled corneas, SEM showed that only the immediate group exhibited superficial cell damage and a significant decrease in the corneal TER compared to the controls and other time points and to the immediate preservative-free latanoprost corneas. In the preserved latanoprost groups, the relative TER values were 18 ± 5%, 110 ± 28%, and 92 ± 10%, for the three respective observation time points.Conclusions: Preservative-free latanoprost can be safely instilled to the corneal epithelium. Latanoprost with 0.02% BAC has an immediate deleterious impact on the corneal epithelium; however, it disappears within 24 hours after instillation.

Eye Irritation Potential of Microglycine and Microglycine-Containing Ointments: An in vitro Study on Reconstructed Human Corneal Epithelium

Objective

To assess the eye tolerability of a buffered ophthalmic solution containing microglycine (sodium hydroxymethylglycinate, mwater^TM) in an in vitro model.

Materials and Methods

A multiple endpoint analysis (MEA) approach was applied to the reconstructed human corneal epithelium (HCE) model. Sodium hydroxymethylglycinate solution (0.04%) and two ophthalmic ointments containing microglycine (Protectorial, containing 0.02% of sodium hydroxymethylglycinate, and Edenight, containing 0.04% of sodium hydroxymethylglycinate) were investigated. The buffered solution and the ointments were tested on HCE after acute (one application in 24 hrs, followed or not by 16 hrs of recovery) or repeated (one application per day for three consecutive days) exposures; benzalkonium chloride (BAK) 0.01% and saline isotonic solution were used as positive and negative controls, respectively. Cellular viability, trans-epithelial electrical resistance (TEER), lactate dehydrogenase (LDH) release and histo-morphology were evaluated.

Results

BAK 0.01% toxicity in HCE was confirmed for the 24+16 hrs acute and repeated exposure protocols, while, after 24–hours acute treatment, only modifications of the superficial cell layer were visible compared with the negative control. Sodium hydroxymethylglycinate had a very good tolerability profile and a neutral impact on the corneal surface after acute or repeated exposure. The Protectorial and Edenight ointments preserved cell viability in the different exposure protocols, suggesting a good local tolerability profile. Modifications of the superficial layers were observed on histo-morphological analysis and confirmed by increased release of LDH after 24+16 hrs acute exposure (+65% and +76% for Protectorial and Edenight, respectively) and TEER values after 24+16 hrs and 72 hrs exposure protocols. These results were dependent on the ointments’ accumulation on the corneal epithelium due to their physical form (semi-solid) and lipophilic properties.

Conclusion

Sodium hydroxymethylglycinate, alone or as part of eye ointments, was found to be non-toxic after acute or repeated exposure in the reconstructed HCE model.

Myopia Outcome Study of Atropine in Children (MOSAIC): an investigator-led, double-masked, placebo-controlled, randomised clinical trial protocol

Background: The Myopia Outcome Study of Atropine in Children (MOSAIC) aims to explore the efficacy, safety, acceptability and mechanisms of action of 0.01% unpreserved atropine for myopia control in a European population. Methods: MOSAIC is an investigator-led, double-masked, placebo-controlled, randomised clinical trial (RCT) investigating the efficacy, safety and mechanisms of action of 0.01% atropine for managing progression of myopia. During Phase 1 of the trial, 250 children aged 6-16 years with progressive myopia instil eye drops once nightly in both eyes from randomisation to month 24. From month 24 to 36  participants are re-randomised in Phase 2 of the trial, into continued 0.01% atropine, and washout, at 1:1 ratio for those participants initially randomised to the intervention arm (n=167), during which any potential rebound effects on cessation of treatment will be monitored. All participants initially assigned to the placebo (n=83) crossover to the intervention arm of the study for Phase 2, and from month 24 to 36, instil 0.01% atropine eye drops in both eyes once nightly. Further treatment and monitoring beyond 36 months is planned (Phase 3) and will be designed dependent on the outcomes of Phase 1. Results: The primary outcome measure is cycloplegic spherical equivalent refractive error progression at 24 months. Secondary outcome measures include axial length change as well as the rebound, safety and acceptability profile of 0.01% atropine. Additional analyses will include the mechanisms of action of 0.01% atropine for myopia control. Conclusions: The generalisability of results from previous clinical trials investigating atropine for myopia control is limited by the predominantly Asian ethnicity of previous study populations. MOSAIC is the first RCT to explore the efficacy, safety and mechanisms of action of unpreserved 0.01% atropine in a predominantly White population.

Safety data on in situ gelling bimatoprost loaded nanovesicular formulations

In vitro cytotoxicity and in vivo acute and 7 days repeat-dose ocular toxicity studies, were conducted in rabbits, in accordance with the Organisation for Economic Co-operation and Development (OECD) guidelines, for bimatoprost loaded nanovesicular aqueous dispersion (BMT-NV) and its in-situ gelling sub-conjunctival implant (BMT-NV-IM). For details on the preparation and evaluation of BMT-NV and its BMT-NV-IM for the control of glaucoma, please refer to 'Bimatoprost loaded nanovesicular long-acting sub-conjunctival in-situ gelling implant: In vitro and in vivo evaluation' (Yadav et al., 2019). The in vivo ocular toxicity was performed only after confirming dermal safety, as required by OECD. Histological evaluation of various ocular tissues, following sub-conjunctival implantation with BMT-NV-IM, was done for ocular tolerance studies.

Myopia Outcome Study of Atropine in Children (MOSAIC): an investigator-led, double-masked, placebo-controlled, randomised clinical trial protocol

Background: The Myopia Outcome Study of Atropine in Children (MOSAIC) aims to explore the efficacy, safety, acceptability and mechanisms of action of 0.01% unpreserved atropine for myopia control in a European population.

Methods: MOSAIC is an investigator-led, double-masked, placebo-controlled, randomised clinical trial (RCT) investigating the efficacy, safety and mechanisms of action of 0.01% atropine for managing progression of myopia. During Phase 1 of the trial, 250 children aged 6-16 years with progressive myopia instil eye drops once nightly in both eyes from randomisation to month 24. No treatment is given during Phase 2 from month 24 to 36 (washout period) for those participants initially randomised to the intervention arm (n=167), during which any potential rebound effects on cessation of treatment will be monitored. All participants initially assigned to the placebo (n=83) crossover to the intervention arm of the study for Phase 2, and from month 24 to 36, instil 0.01% atropine eye drops in both eyes once nightly. Further treatment and monitoring beyond 36 months is planned (Phase 3) and will be designed dependent on the outcomes of Phase 1.

Results: The primary outcome measure is cycloplegic spherical equivalent refractive error progression at 24 months. Secondary outcome measures include axial length change as well as the rebound, safety and acceptability profile of 0.01% atropine. Additional analyses will include the mechanisms of action of 0.01% atropine for myopia control.

Conclusions: The generalisability of results from previous clinical trials investigating atropine for myopia control is limited by the predominantly Asian ethnicity of previous study populations. MOSAIC is the first RCT to explore the efficacy, safety and mechanisms of action of unpreserved 0.01% atropine in a predominantly White population.

Trial registration: ISRCTN: ISRCTN36732601 (04/10/2017), EudraCTdatabase 2016-003340-37 (03/07/2018).

Effects of Anti-Glaucoma Prostaglandin Ophthalmic Solutions on Cultured Human Corneal Epithelial Cells

Purpose: We compare the cytotoxicity of anti-glaucoma prostaglandin ophthalmic solutions on human corneal epithelial cells and elucidate mechanisms of toxicity. Methods: Cell viability was examined using MTS assay, and morphological changes of the cells were observed. Induction of necrosis/apoptosis was measured by colorimetric caspase assay. The production of Reactive oxygen species (ROS) and release of cytokines were analyzed using 2', 7'-dichlorodihydrofluorescein diacetate and bead-based indirect immunofluorescent assay, respectively. Results: Xalatan, Lumigan 0.01%, and Lumigan 0.03% decreased cell viability and induced morphological changes. Xalatan and Lumigan 0.01% induced necrosis. Xalatan, Lumigan 0.01%, Lumigan 0.03%, and Taflotan stimulated ROS production. Travatan and Lumigan 0.03% increased concentrations of Interleukin (IL)-6 and IL-8 in culture media. Conclusions: Xalatan and Lumigan 0.01% ophthalmic solutions demonstrated potent cytotoxicity compared with Lumigan 0.03%, Travatan, Taflotan, and Taflotan UD. Taflotan UD, compared to Taflotan 0.0015%, induced less oxidative stress and apoptotic signalling. The cytotoxicity might be partly associated with benzalkonium chloride.

Ocular Surface Disease and Glaucoma Medications: A Clinical Approach

OBJECTIVES

Ocular surface disease frequently coexists with glaucoma and may be initiated or exacerbated by topical glaucoma medications. We performed a review of current literature to assess the prevalence, causes, and treatment of ocular surface disease in glaucoma patients, specifically those on topical therapy.

METHODS

A Pubmed database search was conducted. A total of 720 articles published from 1972 to 2018 were found in relation with ocular surface disease, glaucoma, and glaucoma medications. Of these, 102 articles were included in this analysis. We included primary and empirical studies for patients on topical glaucoma medications. Exclusion criteria included case reports, non-English studies, and articles unrelated to the primary subject of this review.

RESULTS

Ocular surface disease among normal and glaucomatous eyes was evaluated based on diagnostic testing including clinical examination and questionnaires to determine visual function and quality of life. Glaucoma medications can be associated with toxicities to the ocular surface, most often due to the nature of the preservative included in the medication; however, the incidence of toxicity can be mitigated by the use of preservative free medications, decreased preservative medications, or treatment of dry eye disease. Treatment of glaucoma with laser trabeculoplasty or minimally invasive glaucoma surgeries that spare the conjunctiva and the cornea may avoid or decrease reliance on topical glaucoma medications, potentially avoiding the initiation or progression of ocular surface disease.

CONCLUSIONS

Recognition and treatment of ocular surface disease in glaucoma patients may improve patient quality of life and medication adherence. This may ultimately improve glaucoma treatment outcomes.

Preservative-Free Prostaglandin Analogs and Prostaglandin/Timolol Fixed Combinations in the Treatment of Glaucoma: Efficacy, Safety and Potential Advantages

Glaucoma therapy-related ocular surface disease (OSD) is a serious pathology with a broad spectrum of insidious clinical presentations and complex pathogenesis that undermines long-term glaucoma care. Preservatives, especially benzalkonium chloride (BAK), contained in topical intraocular pressure-lowering medications frequently cause or aggravate OSD in glaucoma. Management of these patients is challenging, and to date often empirical due to the scarcity of controlled long-term clinical trials. Most of the available data are extracted from case series and retrospective analysis. Preservative-free prostaglandins and prostaglandin/timolol fixed combinations are novel options developed to remove the harmful impact of preservatives, especially BAK, upon ocular tissues. Based on what is currently known on the value of preservative-free antiglaucoma therapies it is tempting to speculate how these new therapies may affect the future medical management of all glaucoma patients. This article provides a comprehensive and critical review of the current literature on preservative-free prostaglandins and preservative-free prostaglandin/timolol fixed combinations.

Effects of sustained daily latanoprost application on anterior chamber anatomy and physiology in mice

Latanoprost is a common glaucoma medication. Here, we study longitudinal effects of sustained latanoprost treatment on intraocular pressure (IOP) in C57BL/6J mice, as well as two potential side-effects, changes in iris pigmentation and central corneal thickness (CCT). Male C57BL/6J mice were treated daily for 16 weeks with latanoprost. Control mice were treated on the same schedule with the preservative used with latanoprost, benzalkonium chloride (BAK), or handled, without ocular treatments. IOP and CCT were studied at pre-treatment, 2 "early" time points, and 2 "late" time points; slit-lamp analysis performed at a late time point; and expression of corneal and iridial candidate genes analyzed at the end of the experiment. Latanoprost lowered IOP short, but not long-term. Sustained application of BAK consistently resulted in significant corneal thinning, whereas sustained treatment with latanoprost resulted in smaller and less consistent changes. Neither treatment affected iris pigmentation, corneal matrix metalloprotease expression or iridial pigment-related genes expression. In summary, latanoprost initially lowered IOP in C57BL/6J mice, but became less effective with sustained treatment, likely due to physiological adaptation. These results identify a new resource for studying changes in responsiveness associated with long-term treatment with latanoprost and highlight detrimental effects of commonly used preservative BAK.

Preservatives in glaucoma medication

Preservatives continue to be in widespread use in ophthalmic medications due to the convenience they provide, regulatory requirements and the higher cost of alternatives. Benzalkonium chloride (BAK) remains the most commonly used preservative but there is a trend towards the use of preservative-free (PF) drops for glaucoma, although at a higher price. An extensive body of literature explores BAK toxicity on ocular structures in animal and laboratory studies (in vitro and in vivo). Non-randomised controlled studies have provided some supporting evidence of its toxicity in patients, especially in those with pre-existing ocular surface disease (OSD) or on multiple medications. However, there have been very few randomised controlled trials that compare the same medication with and without BAK preservative. Several of these trials have never been published in any peer reviewed journals. Notwithstanding, those that have been published, have not demonstrated any clear benefits of the BAK-free formulations. Short duration and exclusion of those with OSD are limitations of these studies. There is a lack of evidence of clinically significant harm from a small number of BAK preserved drops in patients without OSD. This means that generally more expensive PF glaucoma medications should only be recommended for those on poly pharmacy or those with OSD but are not necessarily required for all patients.

[Effects of artificial tears on ocular surface in glaucomatous patients with long-term instillation of preserved antiglaucoma eye drops]

PURPOSE

To study the effects of long-term instillation of 0.18% sodium hyaluronate artificial tears VISMED multi on ocular surface in glaucomatous patients with long-term instillation of preserved anti-glaucoma drops.

MATERIAL AND METHODS

The study included 79 patients (40 female and 39 male; 79 eyes in total) with primary open-angle glaucoma (POAG) divided into 3 groups according to disease stage: mild or early (stage I) glaucoma - 15 patients (15 eyes), moderate (stage II) glaucoma - 30 patients (30 eyes), advanced or severe (stage III) glaucoma - 34 patients (34 eyes). Conjunctival and corneal changes were assessed with Norn's test, Schirmer I test and corneal fluorescein staining test. All patients completed Ocular Surface Disease Index (OSDI) questionnaire. Corneal compensated intraocular pressure (IOPcc) was measured using Ocular Response Analyzer (ORA) (Reichert Optics Inc., USA). In addition to hypotensive therapy, all patients received instillations of 0.18% sodium hyaluronate (VISMED multi) three times every day. After 14 days, all examinations were repeated.

RESULTS

The condition of eye surface in patients with moderate and advanced (stage II and III) glaucoma depends on the degree of IOPcc compensation. As glaucoma increases in severity, the pathological changes in the ocular surface progress. Instillations of 0.18% sodium hyaluronate solution lead to significant improvement of the test results in all groups, and in early glaucoma patients it restores all objective indicators to normal values.

CONCLUSION

Treatment with 0.18% sodium hyaluronate solution (VISMED multi) leads to statistically significant (p<0.05) improvement of ocular surface condition in glaucoma patients with long-term instillation of preserved antiglaucoma eye drops.

[Possibilities and limitations of eye drops for glaucoma therapy]

BACKGROUND

In Germany, chronic open-angle glaucoma is mostly treated by daily eye drop application. The possibilities and limitations of this form of therapy are presented. Reasons for the change in the selection of the preferred substances over time are also discussed and the limits of local drug therapy are described.

OBJECTIVES

What effects can be expected of the available drugs?

MATERIALS AND METHODS

The article provides a review of the literature from PubMed and clinical experience.

RESULTS

In chronic open-angle glaucoma, eye drops containing a single agent can achieve an intraocular pressure decrease of 15-35 % compared to the initial pressure level. This is dependent on the substance and is achievable when used as directed. Difficulties in administration are often observed in older patients where regular use over extended periods of time is required. In addition, there are limits in the achievable pressure reduction by combining several active ingredients. Novel systems are being developed for future applications. The idea is to achieve a continuous slow release of the active substance by surgical application of a biodegradable carrier.

CONCLUSION

A treatment regimen which is individually tailored to the individual patient's needs should be developed by the attending physician and the achievement of the set objectives should be monitored at regular intervals. However, restrictions induced by patients due to inadequate adherence or by the drug due to limited efficacy of the drug have to be considered. Therefore, eye drop therapy in open-angle glaucoma is not always sufficient. It should be supplemented in due time by laser or filtering surgery before the affected patients and their optic nerves suffer advanced glaucomatous damage.

TFOS DEWS II iatrogenic report

Dry eye can be caused by a variety of iatrogenic interventions. The increasing number of patients looking for eye care or cosmetic procedures involving the eyes, together with a better understanding of the pathophysiological mechanisms of dry eye disease (DED), have led to the need for a specific report about iatrogenic dry eye within the TFOS DEWS II. Topical medications can cause DED due to their allergic, toxic and immuno-inflammatory effects on the ocular surface. Preservatives, such as benzalkonium chloride, may further aggravate DED. A variety of systemic drugs can also induce DED secondary to multiple mechanisms. Moreover, the use of contact lens induces or is associated with DED. However, one of the most emblematic situations is DED caused by surgical procedures such as corneal refractive surgery as in laser-assisted in situ keratomileusis (LASIK) and keratoplasty due to mechanisms intrinsic to the procedure (i.e. corneal nerve cutting) or even by the use of postoperative topical drugs. Cataract surgery, lid surgeries, botulinum toxin application and cosmetic procedures are also considered risk factors to iatrogenic DED, which can cause patient dissatisfaction, visual disturbance and poor surgical outcomes. This report also presents future directions to address iatrogenic DED, including the need for more in-depth epidemiological studies about the risk factors, development of less toxic medications and preservatives, as well as new techniques for less invasive eye surgeries. Novel research into detection of early dry eye prior to surgeries, efforts to establish appropriate therapeutics and a greater attempt to regulate and oversee medications, preservatives and procedures should be considered.

[Preoperative therapy switch before glaucoma filtration surgery : Influence of the systemic antiglaucomatous and local antiphlogistic therapy on the intraocular pressure]

BACKGROUND

The preoperative switch from local to systemic antiglaucomatous therapy and the additional application of local antiphlogistic drugs represents an important component of perioperative wound healing modulation within the framework of glaucoma filtration surgery.

OBJECTIVE

The aim of the present study was to compare the intraocular pressure (IOP) under a maximum local and oral antiglaucomatous therapy with or without additional application of local steroids.

METHODS

A retrospective clinical analysis of 121 consecutive patients who underwent primary trabeculectomy for open-angle glaucoma in 2013 and who attended the outpatient clinic at least 3 weeks before surgery was carried out. The patients were set on preoperative therapy as follows: continuation of the maximum local antiglaucomatous therapy (with or without local dexamethasone 1 mg/ml 3 times daily) or administration of 750 mg acetazolamide orally per day (with or without local steroids).

RESULTS

The switch to oral antiglaucomatous therapy led to a mean IOP rise of 3.14 mm Hg which was short of statistical significance (p = 0.052). The additional administration of local steroids did not significantly influence the IOP (p = 0.218). Some patients with oral acetazolamide therapy and local steroid application showed large increases in IOP up to 30 mm Hg.

CONCLUSION

The mean IOP rise of 3.14 mm Hg 3 weeks after replacement of antiglaucomatous eye drops by acetazolamide was short of missing statistical significance and seems to be clinically negligible for this relatively short period. The advantages of a lower postoperative fibrotic activity have to be weighed up against this change in IOP. Surprisingly, the effect of administration of local steroids for 3 weeks was minor compared to the effect of the switch from local to oral antiglaucomatous medication. Individual major IOP increases under the preoperative therapy change should be taken into consideration.

Preservative-free bimatoprost 0.03% in patients with primary open-angle glaucoma or ocular hypertension in clinical practice

BACKGROUND

Intraocular pressure (IOP)-lowering medications for primary open-angle glaucoma and ocular hypertension commonly contain preservatives that can cause ocular surface damage in many patients. The purpose of this study was to evaluate the efficacy and tolerability of, and compliance to, preservative-free (PF) bimatoprost 0.03% in patients with primary open-angle glaucoma or ocular hypertension (IOP ≥18 mmHg) in a clinical practice setting.

METHODS

This open-label study observed patients who were switched to PF bimatoprost 0.03% for medical reasons. IOP was measured at baseline and ~12 weeks later at the final visit, and the change in IOP was calculated. Tolerability and continuation of therapy were assessed at two follow-up visits.

RESULTS

A total of 1,830 patients were included in the study, and complete IOP data were available for 1,543 patients. Mean IOP was reduced by 23% from 21.64 mmHg to 16.59 mmHg (P<0.0001). In subgroup analyses, the mean IOP was significantly reduced compared with baseline, regardless of prior therapy, including those previously treated with PF monotherapy. A total of 85.7% of physicians reported the IOP-lowering efficacy of PF bimatoprost 0.03% to be as expected or better than expected. Adverse events (AEs) were experienced by 5.7% of patients, and there were no serious AEs reported. The most common AEs were eye irritation (1.7%) and hyperemia (1.4%). Physician-reported treatment compliance was reported as better than (48.7%) or equal to (43.6%) prior treatment in most patients. Most patients (82%) were expected to continue PF bimatoprost 0.03% after the end of the study.

CONCLUSION

This observational study showed that, in clinical practice, switching to PF bimatoprost 0.03% was associated with a significant IOP reduction from baseline. There was a low AE rate. PF bimatoprost 0.03% may, therefore, be an effective treatment option for patients who are intolerant of preservatives or have an inadequate response to prior IOP-lowering treatments.

Ocular surface toxicity from glaucoma topical medications and associated preservatives such as benzalkonium chloride (BAK)

INTRODUCTION

This review discusses the evidence concerning the effect of topical medications and their preservatives on the ocular surface in glaucoma patients. The role of topical anti-glaucoma medication remains critical in the management of chronic glaucoma worldwide but the beneficial effects of treatment are counterbalanced by the adverse effects of corneal and conjunctival toxicity. Areas covered: This article covers the effect of topical ocular drops and preservatives, particularly benzalkonium chloride, on the cornea and conjunctiva. Both basic science and clinical evidence will be presented. The first part reviews the relationship between ocular surface disease and benzalkonium chloride and the evidence from non-benzalkonium chloride preserved drops. The second part discusses the effects of benzalkonium chloride on the histopathology of the conjunctiva and its impact on clinical care as well as quality of life. Expert opinion: Topical anti-glaucoma medication will continue to be used in the management of this blinding disease for the foreseeable future. Treatment outcomes will benefit from minimized exposure to benzalkonium chloride. The development of alternative preservatives, preservative-free topical options, and non-drop therapeutics such as drug-eluting systems for the delivery of ocular medications, will be very helpful in the care of glaucoma patients.

Acute cytotoxic effects of marketed ophthalmic formulations on human corneal epithelial cells

The purpose of the study was to devise a fast, reliable and sensitive cell viability assay for assessment of acute cytotoxicity on human corneal epithelial cells by using a clinically relevant exposure time. Acute cytotoxic effects of the pharmaceutical excipients benzalkonium chloride (BAC), macrogolglycerol hydroxystearate (MGHS40), polysorbate 80 (PS80) and marketed ophthalmic formulations (Lumigan(®), Monoprost(®), Taflotan(®), Travatan(®), Xalatan(®)) containing these excipients were tested. Human corneal epithelial cell (HCE-T) viability was assessed by measuring the reduction of resazurin to highly fluorescent resorufin. Expression of the tight junction proteins in HCE-T cells were characterized by immunofluorescence staining. Presence of tight junction proteins in HCE-T cells was demonstrated. BAC preserved ophthalmic formulations showed concentration-dependent and time-dependent cytotoxicity to human corneal epithelium. In contrast, no acute cytotoxicity of non-ionic stabilizing/solubilizing excipients (MGSH40 and PS80) or ophthalmic formulation containing these excipients was observed. Marketed ophthalmic formulations used for glaucoma medication show differential toxicity on human corneal epithelial cells. The present study revealed that BAC-preserved ophthalmic formulations were able to induce acute cytotoxic effects even during a clinically relevant exposure time, which was not observed with MGSH40 and PS80 excipients or ophthalmic formulations containing these excipients.

Ocular Tolerability of Preservative-Free Tafluprost and Latanoprost: in vitro and in vivo Comparative Study

Objective:

Detrimental effects of the preserved prostaglandin analogs (PGAs) have been thoroughly documented in the published literature. The current work studied two preservative-free (PF) prostaglandin eye drops: PF tafluprost and PF latanoprost. The aim of the study was to compare these two PF formulations in vitro for viability of the human corneal epithelial (HCE-T) cells and in vivo for ocular tolerability of the rabbit eye.

Method:

Viability of the HCE-T cells was measured by the MTS assay. The SV40-immortalized HCE-T cells were exposed to 100 µL of the drug solutions (at their commercial concentrations) or the culture medium. Ocular irritation was evaluated after repeated instillation of the drug solutions in Japanese white rabbits (Kbl:JW).

Results:

A significant loss of HCE-T cell viability was observed in vitro immediately after the exposure to PF latanoprost formulation but not immediately after the exposure to PF tafluprost formulation. Congruently, PF latanoprost induced in vivo more irritation on the rabbit eye than PF tafluprost.

Conclusion:

Comparing these two PF formulations in vitro and in vivo, it is considered that ocular tolerability of PF tafluprost is better than PF latanoprost. Taking into account the composition of these two PF PGA formulations, the solubilizing agent macrogolglycerol hydroxystearate 40 (MGHS40) contained in PF latanoprost formulation is a plausible cause for the negative effects.

Estimation of the in vitro eye irritating and inflammatory potential of lipopolysaccharide (LPS) and dust by using reconstituted human corneal epithelium tissue cultures

CONTEXT

Eye irritation is a common complaint in indoor environment, but the causes have still not been identified among the multiple exposures in house environments. To identify the potential environmental factors responsible for eye irritation and study the possible mechanisms, an in vitro model for eye irritation is suggested.

MATERIALS AND METHODS

In this study, reconstituted human corneal epithelium (HCE) tissue cultures were used to study the eye irritating and inflammatory potential of lipopolysaccharide (LPS) and dust. HCE tissue cultures were exposed to a range of concentrations of LPS for 6 h and dust for 24 h, respectively. After exposure, viability and secretion of interleukins (IL) IL-1β, IL-8, and tumor necrosis factor (TNFα) were examined. Histology was used to indicate the morphological changes after dust exposure.

RESULTS

Both LPS and dust affected HCE viability. There was an increased level of IL-8 after LPS exposure, while the concentrations of IL-1β and TNFα remained unaffected. Dust exposure resulted in an elevation of both IL-1β and IL-8, but not TNFα. Histology study showed increased vacuolization and reduced thickness after 24 h exposure to 5 mg/mL dust.

DISCUSSION AND CONCLUSION

LPS and dust showed in vitro eye irritating and inflammatory potential, and cytokines/chemokines like IL-1β and IL-8 may be involved in the mechanisms of eye irritation. The HCE tissue culture may be used as an in vitro model to study environmental exposure induced eye irritation and inflammation.

Evaluation of Eye Irritation Potential of Solid Substance with New 3D Reconstructed Human Cornea Model, MCTT HCE(TM)

The eye irritation potential of drug candidates or pharmaceutical ingredients should be evaluated if there is a possibility of ocular exposure. Traditionally, the ocular irritation has been evaluated by the rabbit Draize test. However, rabbit eyes are more sensitive to irritants than human eyes, therefore substantial level of false positives are unavoidable. To resolve this species difference, several three-dimensional human corneal epithelial (HCE) models have been developed as alternative eye irritation test methods. Recently, we introduced a new HCE model, MCTT HCE^TM which is reconstructed with non-transformed human corneal cells from limbal tissues. Here, we examined if MCTT HCE^TM can be employed to evaluate eye irritation potential of solid substances. Through optimization of washing method and exposure time, treatment time was established as 10 min and washing procedure was set up as 4 times of washing with 10 mL of PBS and shaking in 30 mL of PBS in a beaker. With the established eye irritation test protocol, 11 solid substances (5 non-irritants, 6 irritants) were evaluated which demonstrated an excellent predictive capacity (100% accuracy, 100% specificity and 100% sensitivity). We also compared the performance of our test method with rabbit Draize test results and in vitro cytotoxicity test with 2D human corneal epithelial cell lines.

The utility of an artificial substitute to improve corneal sensitivity in glaucomatous patients on chronic therapy with prostaglandin analogs

PURPOSE

To evaluate whether a tear substitute can improve corneal subepithelial nerve plexus and corneal sensitivity in glaucomatous patients.

METHODS

This study was prospective, longitudinal, and single arm. Twenty glaucomatous patients were recruited. All the patients were treated with a prostaglandin analog with preservative for at least 1 year. Preservative-free artificial tears (0.5% tamarind seed polysaccharide 0.5(®) eye drops single-dose preservative free [Oftagen]) were prescribed thrice per day. The participants were subjected to clinical and instrumental evaluation at baseline (T0), after 1 month (T1) and after 3 months (T3) of treatment. All patients were examined with a digital corneal confocal laser-scanning microscope (HRT II Rostock Cornea Module; Heidelberg Engineering GmbH) and Cochet-Bonnet corneal esthesiometer.

RESULTS

After the artificial substitute, corneal and conjunctival sensitivity significantly (P < 0.001) improved at T1 and T3 compared to the baseline. A significant correlation was found between break-up time and both central corneal sensitivity and the number of fibers.

CONCLUSION

The use of a preservative-free artificial substitute in association with a topical therapy with chronic preservative could increase the compliance of patients.

Symptoms and signs of ocular surface disease related to topical medication in patients with glaucoma

Purpose

The aim of this study was to assess signs and symptoms of ocular surface disease (OSD) and the cytomorphological changes of ocular surface in glaucoma patients using preserved antiglaucoma drops.

Methods

In this cross-sectional study, 109 participants (79 patients with topical medication and 30 untreated controls) completed the Ocular Surface Diseases Index (OSDI) questionnaire and underwent an ophthalmic examination, including Schirmer test, tear film breakup time (TBUT), and fluorescein staining. Conjunctival specimens were collected by impression cytology and analyzed by light microscopy using Nelson’s grading scheme (grades 0–3). This classification is based on the nucleus-to-cytoplasm ratios of epithelial cells and the numbers of goblet cells, with grade 2 considered abnormal.

Results

The medication group had significantly shorter TBUT (median [interquartile range]: 6.0 seconds [5.0–8.0 seconds] vs 9.5 seconds [6.0–12.3 seconds]; P<0.03), greater fluorescein staining (1.0 [0.75–1.25] vs 0 [0–0.25]; P<0.001), and higher impression cytology grade than the control group (median [range]: 1.0 [1:2 to 1:6] vs 0.6 [1:2 to 1:4]; P<0.001). The increasing number of drops instilled per day was associated with an increase in fluorescein staining (Spearman’s rho r=0.475; P<0.001) and shorter TBUT (r=−0.278; P=0.014). The OSDI did not discriminate between the two groups.

Conclusion

Clinical tests and impression cytology showed ocular surface damage in patients using preserved antiglaucoma medications. However, there was no statistically and clinically significant difference in symptoms measured by OSDI score between the medication and control groups.