Therapeutic Effects of Sodium Hyaluronate on Ocular Surface Damage Induced by Benzalkonium Chloride Preserved Anti-glaucoma Medications

Glaucoma and Dry Eye Disease: Opportunity to Assess and Treat

Dry eye disease (DED) has been found to occur at a higher prevalence in individuals with glaucoma than in individuals without glaucoma. The relationship between glaucoma and DED may be, in part, a result of glaucoma therapy. Greater number of antiglaucoma medications used and greater number of antiglaucoma eyedrops instilled per day have been associated with ocular surface disease in patients with glaucoma. Use of antiglaucoma medication has also been associated with higher levels of ocular surface inflammatory markers and ocular surface alterations. There is evidence to suggest that antiglaucoma medications with preservatives and, to some extent, antiglaucoma medication formulations without preservatives may contribute to ocular surface signs and symptoms. Trabeculectomy for glaucoma has also been associated with ocular surface signs related to DED; however, there may be benefits of trabeculectomy and other procedures for glaucoma due to reduced use of antiglaucoma medications. Patients with glaucoma with ocular surface disease have been found to have greater ocular surface symptoms, poorer vision-related quality of life, and poorer antiglaucoma medication adherence compared with patients with glaucoma without ocular surface disease. Because of the potential negative impact of DED on patients with glaucoma, patients with glaucoma may benefit from evaluation for DED. Management of DED in patients with glaucoma may include modifications to antiglaucoma medications and use of treatments for DED.

Hyaluronic acid in the treatment of dry eye disease

Dry eye disease (DED) is a highly prevalent and debilitating condition affecting several hundred million people worldwide. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan commonly used in the treatment of DED. This review aims to critically evaluate the literature on the safety and efficacy of artificial tears containing HA used in DED treatment. Literature searches were conducted in PubMed, including MEDLINE, and in Embase via Ovid with the search term: "(hyaluronic acid OR hyaluronan OR hyaluronate) AND (dry eye OR sicca)". A total of 53 clinical trials are included in this review, including eight placebo-controlled trials. Hyaluronic acid concentrations ranged from 0.1% to 0.4%. Studies lasted up to 3 months. A broad spectrum of DED types and severities was represented in the reviewed literature. No major complications or adverse events were reported. Artificial tears containing 0.1% to 0.4% HA were effective at improving both signs and symptoms of DED. Two major gaps in the literature have been identified: 1. no study investigated the ideal drop frequency for HA-containing eyedrops, and 2. insufficient evidence was presented to recommend any specific HA formulation over another. Future investigations assessing the optimal drop frequency for different concentrations and molecular weights of HA, different drop formulations, including tonicity, and accounting for DED severity and aetiology are essential for an evidence-based, individualized approach to DED treatment.

Hyaluronic acid in the treatment of dry eye disease

Dry eye disease (DED) is a highly prevalent and debilitating condition affecting several hundred million people worldwide. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan commonly used in the treatment of DED. This review aims to critically evaluate the literature on the safety and efficacy of artificial tears containing HA used in DED treatment. Literature searches were conducted in PubMed, including MEDLINE, and in Embase via Ovid with the search term: "(hyaluronic acid OR hyaluronan OR hyaluronate) AND (dry eye OR sicca)". A total of 53 clinical trials are included in this review, including eight placebo-controlled trials. Hyaluronic acid concentrations ranged from 0.1% to 0.4%. Studies lasted up to 3 months. A broad spectrum of DED types and severities was represented in the reviewed literature. No major complications or adverse events were reported. Artificial tears containing 0.1% to 0.4% HA were effective at improving both signs and symptoms of DED. Two major gaps in the literature have been identified: 1. no study investigated the ideal drop frequency for HA-containing eyedrops, and 2. insufficient evidence was presented to recommend any specific HA formulation over another. Future investigations assessing the optimal drop frequency for different concentrations and molecular weights of HA, different drop formulations, including tonicity, and accounting for DED severity and aetiology are essential for an evidence-based, individualized approach to DED treatment.

[Effects of Benzalkonium Chloride in Ophthalmic Eyedrop Medications on Corneal Epithelium]

Eyedrops often contain additives other than active pharmaceutical ingredients, such as preservatives. The most frequently used preservative is benzalkonium chloride (BAC). When the ocular surface is exposed to eyedrops, the active pharmaceutical ingredients and additives can cause corneal epithelial disorder. Particularly in clinical settings, there is great interest in corneal epithelial disorders resulting from the use of glaucoma eyedrops, which is inevitable when instilled for a long period of time after the onset of disease. At the authors' institute, glaucoma is treated with consideration of reducing corneal epithelial disorder while ensuring the effect of lowering intraocular pressure by the appropriate choice of eyedrops. In this review, we show the examples of the retrospective studies. Sodium hyaluronate eyedrops are prescribed for corneal epithelial disorders such as superficial punctate keratitis associated with dry eye. Prescribable concentrations of sodium hyaluronate in Japan are 0.1% or 0.3%, and the 0.3% formulation does not contain BAC. The authors' study showed that 0.3% sodium hyaluronate pretreatment reduced the cytotoxicity of BAC in cultured corneal epithelial cells, whereas an in vivo study in mice showed that a 0.3% sodium hyaluronate instillation was suggested and that the drug may enhance the cytotoxicity of separately administered BAC. It is suggested that sodium hyaluronate prolonged the retention of BAC on the ocular surface. However, there have been no reports of this problem in the clinical setting. It is important for ophthalmologists to understand the properties of additives other than the active pharmaceutical ingredients in eyedrops.

Long-term outcomes of the Ahmed glaucoma valve surgery in childhood glaucoma

PURPOSE

To report the rates of success of Ahmed glaucoma valve (AGV) surgery in early childhood glaucoma and factors associated with success.

METHODS

Children with primary congenital or early childhood secondary glaucoma who underwent AGV surgery over a 10-year period (one eye per child) at a single institution were identified. Surgical failure was defined as having one or more of the following: intraocular pressure of >21 mm Hg 3 months postoperatively, reoperation for glaucoma, and vision loss to no light perception.

RESULTS

A total of 178 patients were identified (median age, 5.8 ± 5.5 years): 125 with primary congenital and 53 with secondary childhood glaucoma. The success rate at 1 year was 92% (95% CI, 88%-96%); at 5 years, 64% (95% CI, 55%-73%); and at 10 years, 36% (95% CI, 25%-52%). Younger age at baseline (P = 0.003) and secondary childhood glaucoma (P = 0.045) were associated with lower success.

CONCLUSIONS

The AGV is associated with high short-term success in children with primary congenital glaucoma, but the 10-year success rates are poor. Younger age and secondary childhood glaucoma may be associated with a more refractory outcome.

Why Chain Length of Hyaluronan in Eye Drops Matters

The chain length of hyaluronan (HA) determines its physical as well as its physiological properties. Results of clinical research on HA eye drops are not comparable without this parameter. In this article methods for the assessment of the average molecular weight of HA in eye drops and a terminology for molecular weight ranges are proposed. The classification of HA eye drops according to their zero shear viscosity and viscosity at 1000 s-1 shear rate is presented. Based on the gradient of mucin MUC5AC concentration within the mucoaqueous layer of the tear film a hypothesis on the consequences of this gradient on the rheological properties of the tear film is provided. The mucoadhesive properties of HA and their dependence on chain length are explained. The ability of HA to bind to receptors on the ocular epithelial cells, and in particular the potential consequences of the interaction between HA and the receptor HARE, responsible for HA endocytosis by corneal epithelial cells is discussed. The physiological function of HA in the framework of ocular surface homeostasis and wound healing are outlined, and the influence of the chain length of HA on the clinical performance of HA eye drops is illustrated. The use of very high molecular weight HA (hylan A) eye drops as drug vehicle for the next generation of ophthalmic drugs with minimized side effects is proposed and its advantages elucidated. Consequences of the diagnosis and treatment of ocular surface disease are discussed.

Conjunctival Goblet Cells, the Overlooked Cells in Glaucoma Treatment

Glaucoma is the leading cause of irreversible blindness worldwide. Although no definitive cure exists, lowering of the intraocular pressure decreases the rate of progression in the majority of patients with glaucoma. Antiglaucomatous treatment modalities consist predominantly of chronic use of eye drops. It has become increasingly evident that long-term exposure to eye drops has a significant impact on the ocular surface, and thereby on patient compliance and quality of life. Maintenance of the ocular surface is highly dependent on a stable tear film. Conjunctival goblet cells (GCs) of the ocular surface play an important role in providing the innermost mucin layer of the tear film and are essential for maintaining the ocular surface homeostasis. Recent studies have reported severe side effects of antiglaucomatous drops on GCs. In particular, a preservative containing antiglaucomatous drops have been shown to affect the viability and functions of the GCs. Furthermore, GC density has been suggested as a potential predictor of surgical outcome after filtration surgery. The present review provides an overview of the current literature on the impact of antiglaucomatous eye drops on GCs as well as the impact on the ocular surface. Moreover, the existing evidence of a possible association between GC density and glaucoma filtration surgery outcome is summarized. We conclude that prostaglandin analogs spare the conjunctival GCs more compared with other antiglaucomatous drops and that GCs may be a good predictor of surgical outcome after filtration surgery. Overall, given the multiple functions of GCs in the ocular surface homeostasis, dedicated strategies should be adopted to preserve this cell population during the course of glaucoma.

Efficacy of eye drops containing crosslinked hyaluronic acid and CoQ10 in restoring ocular health exposed to chlorinated water

Purpose:

A prospective, open-label study in 20 professional swimmers evaluated the efficacy and safety of an ophthalmic solution containing crosslinked hyaluronic acid, coenzyme Q10, and vitamin E TPGS in releasing eye irritation and restoring ocular surface damages after prolonged exposure to chlorinated water.

Methods:

Individually, one eye was instilled with the ophthalmic solution and the other used as a comparator. Eye drops were self-administered three times a day for 2 months. Tear film breakup time (primary endpoint), Schirmer I test, beating of eyelashes/min, tear osmolarity, corneal and conjunctival staining with fluorescein, Ocular Surface Disease Index questionnaire, subject satisfaction, visual acuity (secondary endpoints), and Efron Grading Scale were evaluated at screening/baseline (V1), week 1 (V2), week 2 (V3), week 4 (V4), and week 8 (V5).

Results:

After 2 months, breakup time test significantly improved in the treated eyes (+1.67 s) compared to control (−3.00 s) (p = 0.0002). Corneal and conjunctival surfaces of treated eyes recovered significantly compared to control eyes when assessed by fluorescein staining (p < 0.0001), Ocular Surface Disease Index (p < 0.05), and visual analog scale (p = 0.0348) scores. Improvements were also observed with Schirmer I test, beating of eyelashes, and tear osmolarity, despite without statistical significance. Efron Grading Scale was consistent with the other tests. The ocular tolerability was excellent.

Conclusion:

The adequate combination of crosslinked hyaluronic acid, coenzyme Q10, and vitamin E TPGS, contained in the ophthalmic solution VisuXL^®, has been shown to protect ocular surface from potential damages originating from prolonged exposure to chlorinated water. VisuXL may represent a compelling treatment in other situations beyond dry eye syndrome.

Topical hyaluronan alone promotes corneal epithelial cell migration whereas combination with benzalkonium chloride impairs epithelial wound healing

Purpose: To evaluate the effects of topical hyaluronan (HA) on corneal epithelial wound healing when administered with or without benzalkonium chloride (BAC).Methods: A cultured human corneal epithelial cell line (HCE-T) was subjected to in vitro scratch assays and in situ epithelial migration was evaluated in organ-cultured rabbit corneas. The corneal epithelium of C57BL/6J mice was also evaluated to determine in vivo wound healing. An in vivo imaging system was also used to evaluate the effects of HA on eye drop retention on the ocular surface.Results: The findings revealed the promotion of HCE-T migration, in situ rabbit corneal epithelial migration, and in vivo wound healing in mouse corneal epithelium by HA. Pre-treatment with HA also protected against delayed epithelial wound healing in BAC in vitro. However, pre-treatment with 3 mg/mL HA did not show a protective effect against BAC in vivo, but instead delayed epithelial wound healing and increased detection of cleaved caspase-3. This suggested that HA promotes the retention of BAC on the ocular surface. The instilled HA was retained after 15 min, at a significantly higher rate than for phosphate-buffered saline.Conclusions: The combination of HA and BAC impaired wound healing in the corneal epithelium.

Preparation and Evaluation of Topically Applied Azithromycin Based on Sodium Hyaluronate in Treatment of Conjunctivitis

Azithromycin (AZI) eye drops containing sodium hyaluronate (SH) were developed to improve the bioavailability of AZI. Interaction between AZI and SH in the AZI-SH formulation was investigated by differential scanning calorimetry, X-ray diffraction, and ¹H-nuclear magnetic resonance spectroscopy analyses. Moreover, advantages of using SH as an excipient were investigated by comparing physiological properties and pharmacokinetic behaviors of SH-containing AZI eye drops with that of hydroxypropyl methylcellulose (HPMC)-containing formulation. In addition, safety of the developed AZI-SH eye drops was evaluated by in vitro 3-(4,5-dimethyl-2-Thiazyl)-2, 5-diphenyl-2H-tetrazolium bromide assay (MTT assay) and neutral red uptake assay as well as in vivo eye irritation test and acute toxicity test. The results indicated that AZI formed a complex with SH under a slightly acidic condition. The area under the curve (AUC) of AZI in SH-containing formulation was 1.58-fold higher (P < 0.01) than that in HPMC-containing formulation due to the interaction between the amine group of AZI and the carboxyl group of SH, despite of the higher viscosity of HPMC-containing formulation. Safety evaluation showed that AZI-SH eye drops caused no obvious eye irritation and acute toxicity. In conclusion, the developed SH-containing AZI formulation possessing advantages of longer retention time and higher drug availability was a promising drug formulation for topical ocular therapy.

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.

Real-life results of switching from preserved to preservative-free artificial tears containing hyaluronate in patients with dry eye disease

Background

Dry eye disease (DED) is a chronic, multifactorial disease of the ocular surface leading to discomfort, visual disturbance, and tear film instability, with potential damage to the ocular surface.

Aim

The aim of this study was to assess the clinical benefit of a switch from preserved to preservative-free artificial tears (ATs) containing hyaluronate in patients with DED.

Materials and methods

This is a nationwide, multicenter, noninterventional, and transversal observational survey.

Results

The mean age was 51.0±15.4 years, ranging from 6 to 96 years. The majority (61.4%) was female. The mean Ocular Surface Disease Index (OSDI) before the switch was surprisingly high at 56.0±23.5, and 73.0% of the patients had superficial punctate keratitis (SPK). The mean duration of use of preserved ATs before the switch was 15.8±12.1 months. OSDI scores and the presence of SPK correlated with the patients’ ages but were independent of the duration of treatment with the preserved AT. The patients using ATs containing “soft” or “vanishing” preservatives presented exactly the same clinical pattern (level of OSDI and frequency of SPK) as those using ATs containing classical preservatives such as benzalkonium chloride (BAK). After switching to preservative-free AT containing hyaluronate (Hyabak^®), the OSDI of 97.0% of the patients improved, decreasing from an average of 56.0 to an average of 28.2, with 23% of patients reporting a normal value of OSDI. The SPK frequency as well improved dramatically, with a frequency of positive fluorescein staining dropping from 73% to 46.1% of patients. A total of 94.0% of the patients considered that they preferred being treated with the preservative-free AT.

Conclusion

In patients suffering from DED and treated with a preserved AT, switching to a preservative-free AT provides clinical benefit by decreasing the severity of DED and reducing the prevalence of SPK, even after only 3 weeks of daily use of the preservative-free AT.

Biomarkers of ocular surface disease using impression cytology

Impression cytology (IC) is a technique which permits the retrieval of the outermost layer of ocular surface cells via the use of various types of filters. It is a minimally invasive method of evaluating human conjunctival epithelial cell morphology in the diagnosis of dry eye disease, a common and distressing disorder associated with ageing, contact lens wear, autoimmune disorders and refractive (LASIK) surgery. IC may also be utilized in the diagnosis of other ocular diseases, such as keratoconus and thyroid orbitopathy. More recently, IC has been utilized for the subsequent investigation of gene and protein expression of conjunctival cells in order to identify novel diagnostic biomarkers and to further our understanding of the mechanisms underlying ocular surface disease. This review will therefore examine the literature concerning the role of IC in identifying cellular markers of eye disease, systemic diseases with ocular involvement and potential novel therapeutic targets.

Design and optimization of a novel implantation technology in contact lenses for the treatment of dry eye syndrome: In vitro and in vivo evaluation

Contact lenses are widely used for ophthalmic drug delivery, but incorporation of drug or formulation in the contact lenses affects its optical and physical property. In the present study, we have designed a novel hyaluronic acid (HA)-laden ring implant contact lenses (modified cast moulding method), to circumvent the changes in critical lens property. The objective was to improve the ocular residence time of HA, by providing sustained ocular HA delivery through implant contact lenses for the treatment of dry eye syndrome. Optimization of HA-implant was carried out using 3² factorial design by tailoring the amount of cross linker and thickness of implant, to achieve sustained HA release with constraint on effective ion diffusivity. The in vivo pharmacokinetic study in rabbit tear fluid showed sustained HA release up to 15days, by fabricating implant (80μgHA loading) with 78.4μm thickness (total thickness of lens=100μm) using 0.925% of cross linker, with effective ion diffusivity>1.5×10^-6mm²/min. In vivo efficacy study in benzalkonium chloride induced dry eye syndrome rabbits showed faster healing with implant contact lenses in comparison to positive control group. The study demonstrated the promising potential of implantation technology to deliver hyaluronic acid without compromising optical and physical properties of contact lens.

STATEMENT OF SIGNIFICANCE

The limitation of contact lenses to be used as therapeutic device for controlled drug delivery is focused in this study. Incorporation of drug or formulation in the biomaterial affects the optical and physical property of contact lenses. The significance of project was to design a novel hyaluronic acid-laden ring implant contact lenses, to by-pass the changes in critical property of biomaterial.